HSDPA Description

Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd

RAN

HSDPA Description Issue 02

Date 2008-07-30

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RAN HSDPA Description Contents

Issue 02 (2008-07-30) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd

iii

Contents

1 HSDPA Change History.......................................................................................................1-1

2 HSDPA Introduction ............................................................................................................2-1

3 HSDPA Principles.................................................................................................................3-1 3.1 HSDPA Protocol Architecture ................................................................................................................. 3-1 3.2 HSDPA Physical layer ............................................................................................................................ 3-2

3.2.1 Overview of HSDPA Physical Layer .............................................................................................. 3-2 3.2.2 HSDPA Physical Channels ............................................................................................................. 3-3 3.2.3 Timing of HS-DSCH Related Physical Channels ............................................................................ 3-5

3.3 HSDPA MAC-hs Layer........................................................................................................................... 3-6 3.3.1 MAC-hs on the UTRAN Side ........................................................................................................ 3-7 3.3.2 MAC-hs on the UE Side ................................................................................................................ 3-8 3.3.3 HARQ Protocol ............................................................................................................................. 3-9

4 HSDPA Algorithms ..............................................................................................................4-1 4.1 Overview of HSDPA-Related Algorithms................................................................................................ 4-1

4.1.1 HSDPA-Related Algorithms Involved in a Call Process .................................................................. 4-2 4.1.2 QoS Management of Services Mapped on HSDPA ......................................................................... 4-3

4.2 HSDPA Flow Control in NodeB.............................................................................................................. 4-7 4.2.1 Overview of NodeB HSDPA Flow Control..................................................................................... 4-7 4.2.2 Signaling of HSDPA Flow Control ................................................................................................. 4-7 4.2.3 Flow Control Policies .................................................................................................................... 4-9 4.2.4 Adaptive Capacity Allocation Based on Uu Rate .......................................................................... 4-12 4.2.5 Iub Shaping ................................................................................................................................. 4-12 4.2.6 Adaptive Adjustment of Available HSDPA Bandwidth .................................................................. 4-13

4.3 HSDPA MAC-hs Scheduling ................................................................................................................ 4-15 4.4 HSDPA TFRC Selection ....................................................................................................................... 4-18

4.4.1 Overview of TFRC Selection ....................................................................................................... 4-18 4.4.2 CQI Adjustment........................................................................................................................... 4-21

4.5 HSDPA Power Resource Management .................................................................................................. 4-22 4.5.1 Overview of Power Resource Management .................................................................................. 4-22 4.5.2 Dynamic Power Resource Allocation ........................................................................................... 4-22

4.6 HSDPA Code Resource Management.................................................................................................... 4-23 4.6.1 Overview of Code Resource Management .................................................................................... 4-23



Contents RAN

HSDPA Description

iv Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd

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4.6.2 RNC-Controlled Static Code Allocation ....................................................................................... 4-24 4.6.3 RNC-Controlled Dynamic Code Allocation.................................................................................. 4-25 4.6.4 NodeB-Controlled Dynamic Code Allocation ............................................................................... 4-27

4.7 Other HSDPA Related Algorithms......................................................................................................... 4-27 4.7.1 HSDPA Cell Load Control ........................................................................................................... 4-27 4.7.2 HSDPA Mobility Management..................................................................................................... 4-27 4.7.3 HSDPA Channel Switching.......................................................................................................... 4-28 4.7.4 HSDPA TX Diversity................................................................................................................... 4-29

5 HSDPA Parameters ...............................................................................................................5-1

6 HSDPA Reference Documents............................................................................................6-1



RAN HSDPA Description 1 HSDPA Change History


1-1

1 HSDPA Change History

HSDPA Change History provides information on the changes between different document versions.

Document and Product Versions

Table 1-1 Document and product versions

Document Version

RAN Version RNC Version NodeB Version

02 (2008-07-30) 10.0 V200R010C01B061 V100R010C01B050 V200R010C01B041

01 (2008-05-30) 10.0 V200R010C01B051 V100R010C01B049 V200R010C01B040

Draft (2008-03-20) 10.0 V200R010C01B050 V100R010C01B045

There are two types of changes.

l Feature change: refers to the change in the HSDPA feature of a specific product version. l Editorial change: refers to changes in information that has already been included, or the

addition of information that was not provided in the previous version.

02 (2008-07-30) This is the document for the second commercial release of RAN10.0.

Compared with 01(2008-05-30) of RAN10.0, issue 02 (2008-07-30) of RAN10.0 incorporates the changes described in the following table.



1 HSDPA Change History RAN

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Change Type Change Description Parameter Change

Feature change None. The parameters that are changed to be non-configurable are listed as follows: l MAC-hs Discard timer The added parameters are listed as follows: l Hsdpa Switch The deleted parameters are listed as follows: l flow control switch The parameters modified are listed as follows: l SPI weight is modified to Weight

of SPI l H Retry timer is modified to H

Retry Timer Length

Editorial change A parameter list is added. See chapter 5 HSDPA Parameters.

None.

01 (2008-05-30) This is the document for the first commercial release of RAN10.0.

Compared with draft (2008-03-20) of RAN10.0, issue 01 (2008-05-30) of RAN10.0 incorporates the changes described in the following table.


CQI filtering of 4.4.2 CQI Adjustment is removed.

The parameters that are changed to be non-configurable are listed as follows: l CQI Filter Alpha

Feature change

None The parameters renamed are described as follows: l Discard Rate Threshold is

modified to Discard Rate. l Time Delay Threshold is

modified to Time Delay. l The name of CQI Adjustment

Algorithm Switch is modified to CQI Adjust Algorithm Switch.



RAN HSDPA Description 1 HSDPA Change History


1-3


Editorial change General documentation change: l The HSDPA Parameters is

removed because of the creation of RAN10.0 parameter reference.

l HSDPA Flow Control in NodeB is reorganized.

l The structure is optimized.

None.

Draft (2008-03-20) This is the draft of the document for first commercial release of RAN10.0.

Compared with issue 03 (2008-01-20) of RAN6.1, this issue incorporates the changes described in the following table.

Change Type

Change Description Parameter Change

HSDPA supports SRB, IMS and VoIP. The description is added to 2 HSDPA Introduction. For details, refer to Mapping of Signaling and Traffic onto Transport Channels in Radio Bearers.

None.

HSDPA supports HS-DPCCH preamble. For details, refer to Power Control of HS-DPCCH in Power Control.

None.

HSDPA Flow Control in NodeB, HSDPA MAC-hs Scheduling, and CQI Adjustment are enhanced to support SRB, IMS and VoIP .

None.

The CQI adjustment, maximum HARQ retransmission, MAC-hs flow control policy, and scheduling policy are configured on the basis of SPI. For details, refer to 4.1.2 QoS Management of Services Mapped on HSDPA.

None.

CQI adjustment based on residual BLER is added for VoIP. For details, refer to 4.4.2 CQI Adjustment is removed.

The parameters added are as follows: l CQI Adjust

Algorithm Switch l Residual Bler

Target

Feature change

The scheduling algorithm is enhanced to support SRB, IMS, and VoIP. The description is added to 4.3 HSDPA MAC-hs Scheduling.

The parameters added are as follows: l EPF Schedule

Algorithm Switch l MAC-hs Discard



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Change Type

Change Description Parameter Change

timer

Unlimited capacity allocation policy is added to enhance the flow control algorithm to support VoIP, IMS, and SRB. Iub QoS management is added to Iub shaping to provide differentiated service. The SPI weight parameter is considered in flow control. The description is added to 4.2 HSDPA Flow Control in NodeB.

The parameter Flow Control Algorithm Switch is added.

Editorial change

General documentation change is as follows: l The document is reorganized. l Implementation information has been moved to a

separate document. l The Maintenance Information About HSDPA is

removed. l The handover information about HSDPA has been

moved to Intra-Frequency Handover and Inter-Frequency Handover.

None.



RAN HSDPA Description 2 HSDPA Introduction


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2 HSDPA Introduction

HSDPA (High Speed Downlink Packet Access) is an important feature of 3GPP R5. As a downlink (DL) high-speed data transmission solution, it has a theoretical maximum rate of 14.4 Mbit/s on the Uu interface.

The main features of HSDPA are as follows:

l Each subframe transmitted over the Uu interface has a size of 2 ms. l The Hybrid Automatic Repeat Request (HARQ) and Adaptive Modulation and Coding

(AMC) technologies are applied at the physical layer. l The high-order 16QAM modulation mode is used to improve spectral efficiency. l Both code division and time division are used to schedule User Equipments (UEs).

HSDPA improves the performance of UMTS network in the following aspects:

l Higher peak transmission rate in the downlink l The highest rate reaches 14.4 Mbit/s. l Shorter service delay l HSDPA enhances the subscriber experience with high-speed services, such as receiving

e-mails and browsing web pages. l Higher utilization of DL codes and power

The HSDPA capabilities are as follows:

l Peak rate per cell: 14.4 Mbit/s l Peak rate per user: 14.4 Mbit/s l Maximum number of users per cell: 64 l Multiple RABs: 3 PS RABs l SRB over HSDPA l HSDPA over Iur l VoIP over HSPA l IMS signaling over HSPA l HS-DPCCH Preamble l F-DPCH



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Network Elements Involved The following table describes the Network Elements (NEs) involved in HSDPA.

Table 2-1 NEs involved in HSDPA

UE NodeB RNC MSC Server MGW SGSN GGSN HLR

√ √ √ – – – – –

NOTE l – = NE not involved l √ = NE involved UE = User Equipment, RNC = Radio Network Controller, MSC Server = Mobile Service Switching Center Server, MGW = Media Gateway, SGSN = Serving GPRS Support Node, GGSN = Gateway GPRS Support Node, HLR = Home Location Register

Impact l Impact on System Performance

HSDPA increases the system capacity and shortens the data transmission delay. l Impact on Other Features

The impact of HSDPA on other RAN features is as follows: − HSDPA requires the support of power control, load control, admission control, and

mobility management. − HSDPA and other features have influences on each other.



RAN HSDPA Description 3 HSDPA Principles


3-1

3 HSDPA Principles

The principles of HSDPA cover the technical aspects of the feature:

l HSDPA Protocol Architecture l HSDPA Physical layer l HSDPA MAC-hs Layer

3.1 HSDPA Protocol Architecture In the protocol architecture of HSDPA, the MAC-hs is added to both the UE side and the NodeB side to implement HSDPA.

Figure 3-1 shows the HSDPA protocol architecture without the MAC-c/sh.

Figure 3-1 HSDPA protocol architecture without the MAC-c/sh

PHY: Physical Layer TNL: Transport Network Layer

Figure 3-2 shows the HSDPA protocol architecture with the MAC-c/sh.



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Figure 3-2 HSDPA protocol architecture with the MAC-c/sh

The differences between the HSDPA protocol architecture and the R99 protocol architecture are as follows:

l RLC and MAC-d are unchanged. l The HS-DSCH FP is added to handles the data transport from SRNC to CRNC if the Iur

interface is involved and the data transport between CRNC and NodeB. In R99, it is the DCH FP that handles such data transport.

l A new entity called MAC-hs is added at the MAC layer of both UE and NodeB. The MAC-hs handles new functions, such as HARQ and HS-DSCH scheduling.

l There are two types of MAC protocol configurations on the UTRAN side: − Configuration with the MAC-c/sh: The MAC-c/sh implements flow control between

MAC-d, MAC-c/sh, and MAC-hs. − Configuration without MAC-c/sh: The MAC-hs and HS-DSCH FP implement flow

control between MAC-hs and MAC-d over Iub/Iur.

3.2 HSDPA Physical layer At the physical layer of the UTRAN side, the data streams (transport block or transport block set) from the MAC layer are channel coded and mapped onto physical channels. There are three types of HSDPA physical channels, that is, High Speed Shared Control Channel (HS-SCCH), High Speed Physical Downlink Shared Channel (HS-PDSCH), and High Speed Dedicated Physical Control Channel (HS-DPCCH).

l Overview of HSDPA Physical Layer l HSDPA Physical Channels l Timing of HS-DSCH Related Physical Channels

3.2.1 Overview of HSDPA Physical Layer The basic downlink channel configuration for a UE consists of one or several HS-PDSCHs, one associated DPCH, and several HS-SCCHs. In any given TTI, a UE can use a maximum of one HS-SCCH.





3-3

Figure 3-3 Physical channels from the view of an HSDPA UE

When Fractional-Dedicated Physical Control Channel (F-DPCH) is configured, all RABs/SRBs are carried on HS-DSCH. The associated DPCH is replaced with the F-DPCH and there is no DPDCH

The basic uplink channel configuration of HSDPA is the same as that of R99, except that one HS-DPCCH is added for one UE.

Seen from the UE side, the processing at the HSDPA-related physical layer is as follows:

l In each TTI, the UE detects the HS-SCCH channel to check whether the UE is scheduled or not. − If the UE is scheduled, it demodulates and decodes the data from HS-PDSCHs

specified by the related HS-SCCH. An ACK or NACK will be generated on the basis of the decoding result of HS-PDSCHs and will be sent to the serving cell through HS-DPCCH.

− If the UE is not scheduled, it does not demodulate or decode the data from HS-PDSCHs.

l The channel quality indicator (CQI) is periodically reported through the HS-DPCCH regardless of whether the UE is scheduled. CQI is a key input for Transport Format and Resource Combination (TFRC) selection and scheduling based on channel quality at the MAC-hs layer.

Seen from the UTRAN side, the processing at the HSDPA-related physical layer is as follows:

l Multiple UEs can be multiplexed in the code domain within an HS-DSCH TTI. This process is called code division in one TTI.

l The physical resources of HS-DSCH are time shared by all HS-DSCH UEs in the cell.

3.2.2 HSDPA Physical Channels The HSDPA physical channels are as follows:

l HS-SCCH l HS-PDSCH l HS-DPCCH

HS-SCCH The High Speed Shared Control Channel (HS-SCCH) is a downlink physical channel used to carry downlink signaling related to High Speed Physical Downlink Shared Channel (HS-PDSCH). The HS-SCCH has a fixed rate of 60 kbit/s (SF = 128). The following figure shows the subframe structure of the HS-SCCH.




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Figure 3-4 Subframe structure of the HS-SCCH

The HS-SCCH transmits the following control information:

l HS-PDSCH channelization code set information l HS-PDSCH modulation scheme information l Transport block size information l Hybrid ARQ process information l Redundancy and constellation version l New data indicator l UE identify

HS-PDSCH The High Speed Physical Downlink Shared Channel (HS-PDSCH) is used to carry the HS-DSCH data. The HS-PDSCH SF can be 16 only. The modulation mode of HS-PDSCH is QPSK or 16QAM.

Each cell provides a maximum of 15 HS-PDSCH codes. The UE of category 10 supports a maximum of 15 HS-PDSCH codes and the 16QAM modulation mode, with the peak rate of 14.4 Mbit/s on the Uu interface.

Figure 3-5 shows the subframe structure of the HS-PDSCH.

Figure 3-5 Subframe structure of the HS-PDSCH

In the figure, M is the number of bits per modulation symbol.





3-5

l For QPSK, M = 2. l For 16QAM, M = 4.

HS-DPCCH The High Speed Dedicated Physical Control Channel (HS-DPCCH) carries uplink feedback signaling related to HS-PDSCH. It has a fixed rate of 15 kbit/s (SF = 256, that is, 10 bits per timeslot).

The feedback signaling consists of Hybrid Automatic Repeat Request-Acknowledgement/Negative Acknowledgement (HARQ-ACK/NACK) and Channel Quality Indicator (CQI). The HARQ-ACK/NACK is carried in the first timeslot of the HS-DPCCH subframe, and the CQI is carried in the second and the third timeslots of the subframe.

Figure 3-6 shows the subframe structure of the HS-DPCCH.

Figure 3-6 Subframe structure of the HS-DPCCH

3.2.3 Timing of HS-DSCH Related Physical Channels

Timing of the HS-SCCH and HS-PDSCH Figure 3-7 shows the timing of the HS-SCCH and HS-PDSCH.

The start bit of HS-SCCH subframe 0 is aligned with the start bit of the P-CCPCH frame. The HS-PDSCH starts two timeslots later than the HS-SCCH.




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Figure 3-7 Timing of the HS-SCCH and HS-PDSCH

Timing of the Uplink DPCCH, HS-DPCCH, and HS-PDSCH on the UE Side Figure 3-8 shows the timing of the uplink Dedicated Physical Control Channel (DPCCH), HS-PDSCH, and HS-DPCCH at the UE.

After receiving an HS-PDSCH subframe, the UE sends a feedback about 19,200 chips later.

Figure 3-8 Timing of the uplink DPCCH, HS-DPCCH, and HS-PDSCH at the UE

3.3 HSDPA MAC-hs Layer This describes the following:

l MAC-hs on the UTRAN Side l MAC-hs on the UE Side l HARQ Protocol





3-7

3.3.1 MAC-hs on the UTRAN Side The MAC-hs on the UTRAN side manages the physical resources allocated to HS-DSCH.

The MAC-hs consists of the following four different functional entities:

l Flow control l Scheduling l TFRC selection: Transport Format and Resource Combination selection l HARQ: Hybrid Automatic Repeat reQuest

Figure 3-9 shows the MAC-hs architecture on the UTRAN side.

Figure 3-9 MAC-hs architecture on the UTRAN side

The flow control entity controls the HSDPA data flow between RNC and NodeB.

l Purpose: to reduce the transmission time of HSDPA data on the UTRAN side and to reduce the data discarded and retransmitted when the Iub interface or Uu interface is congested.

l The transmission capabilities of the Uu interface and Iub interface are taken into account in a dynamic manner in the flow control. For details of flow control, refer to 4.2 HSDPA Flow Control in NodeB.

The scheduling entity handles the priority of the queues and schedules the priority queues or NACK HARQ processes of the HS-DSCH UEs in a cell to be transmitted on the HS-DSCH related physical channels in each TTI.




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l Purpose: to achieve considerable cell throughput capability and to satisfy user experience.

l The selection is implemented through the scheduling algorithm based on channel quality or QoS. For details of scheduling, refer to 4.3 HSDPA MAC-hs Scheduling.

The HARQ entity handles the HARQ protocol for each HS-DSCH UE.

l Each HS-DSCH UE has one HARQ entity on the MAC-hs of the UTRAN side to handle the HARQ functionality.

l One HARQ entity can support multiple instances (HARQ processes) of stop and wait HARQ protocols. Based on the status reports from HS-DPCCH, a new transmission or retransmission is determined. For details of HARQ protocol, refer to 3.3.3 HARQ Protocol.

The TFRC selection entity selects an appropriate transport format and resource for the data to be transmitted on HS-DSCH.

l The transport format includes the transport block size and modulation scheme. The resource includes the power resource and code resource of HS-PDSCH.

l Transport Format and Resource Combination (TFRC) for each UE is channel quality based, where AMC is the key technique. For details of TFRC selection, refer to 4.4 HSDPA TFRC Selection.

3.3.2 MAC-hs on the UE Side Figure 3-10 shows the MAC-hs architecture on the UE side.

Figure 3-10 MAC-hs architecture on the UE side

The functional entities are described as follows:

l The HARQ entity handles the HARQ protocol on the receiver side. For example, it can generate ACKs or NACKs.

l The reordering queue distribution entity routes the MAC-hs PDUs to the correct reordering buffer based on the queue ID.





3-9

l The reordering entity reorders the received MAC-hs PDUs according to their transmission sequence number (TSN) and the TSN may be out of sequence because of parallel HARQ processes. For each queue ID, one reordering entity is configured on the UE.

l The disassembly entity extracts the MAC-d PDUs from the MAC-hs PDUs and delivers them to the higher layer.

3.3.3 HARQ Protocol The HARQ protocol is based on the stop and wait ARQ scheme, and supports chase combining and incremental redundancy combining.

Figure 3-11 shows the principle of HARQ protocol.

Figure 3-11 Principle of the HARQ protocol

The following topic describes the protocol by taking one UE as an example.

l In a given TTI, the NodeB initiates data transmission of a new transport block (TB) to the UE. Before transmission over the Uu interface, the TB is channel coded at the physical layer, where systematic and parity bits are generated.

l Because of errors in the Uu interface, the receiver UE cannot decode the TB successfully. Therefore, it generates an HARQ-NACK message and sends it to the NodeB through the uplink HS-DPCCH.

l The NodeB retransmits the TB after receiving the NACK from the UE. l The channel coding bits in original transmission and subsequent retransmissions are

buffered on the UE and then are soft-combined to improve the probability of successfully decoding the TB.

The ARQ combining scheme is based on incremental redundancy. Different sets of channel coding bits of the TB can be chosen in the retransmission. Chase combining is considered to be a particular case of incremental redundancy, in which the same systematic and parity bits as those used in the initial transmission are retransmitted.

Compared with retransmission at the RLC layer, HARQ has the following benefits:




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l The round trip time at the physical layer is approximately 12 ms, much shorter than that at the RLC layer. The round trip time at the RLC layer may reach hundreds of milliseconds.

l Soft combining improves the efficiency of the physical layer resource.

The round trip time at the physical layer is 12 ms. Therefore, it is necessary for one UE to have multiple parallel instances (HARQ processes) of the stop and wait HARQ protocol to increase the Uu interface throughput.

One issue in the receiver caused by multiple HARQ processes is that, in a specific time window, the TBs may arrive out of sequence. Therefore, it is necessary to have reordering functionality on the receiver side.



RAN HSDPA Description 4 HSDPA Algorithms


4-1

4 HSDPA Algorithms

The algorithms of HSDPA are as follows:

l Overview of HSDPA-Related Algorithms l HSDPA Flow Control in NodeB l HSDPA MAC-hs Scheduling l HSDPA TFRC Selection l HSDPA Power Resource Management l HSDPA Code Resource Management l Other HSDPA Related Algorithms

4.1 Overview of HSDPA-Related Algorithms l HSDPA-Related Algorithms Involved in a Call Process l QoS Management of Services Mapped on HSDPA



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4.1.1 HSDPA-Related Algorithms Involved in a Call Process

Figure 4-1 HSDPA-Related Algorithms Involved in a Call Process

Step 1 When a cell is set up, the initial allocation of power and codes for HSDPA are allocated. After that, the power and code resource available for HS-DSCHs in a HSDPA cell are dynamically adjusted by the algorithms of 4.5 HSDPA Power Resource Management and 4.6 HSDPA Code Resource Management. R99 and HSDPA can dynamically share the resource of the cell in this way.

Step 2 When one user initiates a service at the beginning of RAB setup procedure, the channel mapping algorithm determines whether the RAB should be mapped onto the HS-DSCH or DCH depending on the service Qos attributes. QoS of the service is mapped to the parameters of radio bearer, such as SPI, discard timer, and GBR for HS-DSCH bearer. For details of radio bearers, refer to Mapping of Signaling and Traffic onto Transport Channels and Mapping of Combined Services onto Transport Channels (in Radio Bearers).

Step 3 RAB is set up after admission control (in Load control). Admission control determines whether the system resources are enough to accept a new user's access request. Data transport begins after the RAB is set up. Data transport of HS-DSCH bearer is controlled by the functions such as 4.2 HSDPA Flow Control in NodeB, 4.3 HSDPA MAC-hs Scheduling, and 4.4 HSDPA TFRC Selection.

Step 4 During the HS-DSCH transport, the movement of the user will trigger the mobility management. For example, the best cell change occurring in the active set may trigger HS-DSCH serving cell change or channel switching between HS-DSCH and DCH. For details, refer to Intra-Frequency Handover, Inter-Frequency Handover, and Inter-RAT Handover Description.





4-3

Step 5 Load control also manages the overload situation besides admission control. Load control needs to reserve enough resource to ensure the QoS of the service. HS-DSCH scheduling provides the measurement of GBP, PBR, and DL transmit power and takes it as the input to load control.

Step 6 After HSDPA is introduced, there is one more UE state, that is, CELL_DCH (HS-DSCH). Channel switching between HS-DSCH and DCH and channel switching between HS-DSCH and FACH are introduced. The channel switching may be triggered by mobility or change of traffic volume. For details, refer to 4.7.3 HSDPA Channel Switching.

----End

4.1.2 QoS Management of Services Mapped on HSDPA

QoS Requirements of Different Services Different services, such as SRB, IMS signaling, VoIP, streaming, interactive, and background services, can be mapped on HSDPA.

The requirements for the QoS of different services are as follows:

l IMS/SRB: Signaling has a high requirement for transmission delay. If the requirement cannot be met, the service may be affected. For example, an SRB delay may lead to a handover delay. The average rate of signaling is lower than 20 kbit/s.

l VoIP: The VoIP service is highly delay sensitive. The end-to-end delay of a voice frame should be shorter than 250 ms. The tolerant frame error rate is about 1%. The average rate of the VoIP service with the header compressed is about 20 kbit/s.

l Streaming: The streams at the receiver end should be continuous. Compared with VoIP, the streaming service has a relatively low delay sensitivity, because a buffer that can avoid jitter for several seconds is configured at the receiver end. When the rate of the streaming service is equal to or higher than the GBR, the QoS can be guaranteed.

l BE (background and interactive): The data rate at the service source end can reach a high value, for example, several Mbit/s during a burst. The BE service has a low requirement for transmission delay but has a high requirement for reliable transmission.

QoS Parameters Mapped onto the MAC-hs Layer of the NodeB l MAC-hs Discard timer: An MAC-d PDU in an MAC-hs queue is discarded if the waiting

time exceeds the length of this discard timer. It is an optional IE on the Iub interface. For the VoIP service, the timer is set to 100 ms. For the BE and streaming services, the timer may not be set. For an MAC-hs queue configured with the discard timer, the scheduler should send out the MAC-d PDUs before expiry of the timer.

l Scheduling Priority Indicator (SPI): This parameter specifies the scheduling priority of an MAC-hs queue. The priority is derived from the Traffic Class, Traffic Handling Priority, and User Priority that are mapped onto this queue. For details, refer to Table 4-2. The service-oriented control algorithms are configured on an SPI basis on the NodeB side. For example, the QoS-oriented algorithms, such as the flow control algorithm, scheduling algorithm, CQI adjustment algorithm, and maximum number of HARQ process retransmissions, are all configured on an SPI basis on the NodeB side. For details, refer to Table 4-3. − For details of setting EPF Schedule Algorithm Switch, refer to 4.3 HSDPA MAC-hs

Scheduling.




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− For details of setting Flow Control Algorithm Switch, refer to 4.2 HSDPA Flow Control in NodeB.

− For details of setting CQI Adjust Algorithm Switch, Max Retransmission Count, and Residual Bler Target, refer to 4.4.2 CQI Adjustment.

The user priority–oriented parameters are also configured on an SPI basis on the NodeB side. For example, the weight factor corresponding to the user priority is named Weight of SPI on the NodeB side. For details, refer to Table 4-2.

l Guaranteed Bit Rate (GBR): It is configured on an MAC-hs queue basis. For the streaming service, the GBR specifies the rate that can meet the requirement of the user for viewing and the GBR of a queue is determined by the NAS. For the BE service, the GBR specifies the required minimum rate for the service of the users in the RAN. The GBR of a BE service user is set through the SET USERGBR command on the RNC side. The setting is based on the user priority, namely, gold user, silver user, or copper user. Services with different QoS requirements require different QoS guarantee policies. For example, the VoIP service has a high requirement for delay. To limit the delay caused by flow control or scheduling within a proper range, the algorithm grants the VoIP queue a priority to occupy resources first. The streaming service has a high requirement for GBR. Therefore, the scheduling and flow control algorithms guarantee that the average rate of the service is not lower than the GBR during Iub traffic distribution and Uu resources allocation. The BE service has a high requirement for reliability, which can be achieved through more retransmissions on the Uu interface.

Mapping of the Scheduling Priority Indicator

Figure 4-2 Mapping of the Scheduling Priority Indicator

l Scheduling Priority Indicator (SPI) is the relative priority of the HS-DSCH FP data frame and the SDUs included. The SPI is set according to the Traffic Class (TC), Traffic Handling Priority (THP) of the interactive service, and User Priority. The SPI is set on the RNC LMT and sent to the NodeB through NBAP signaling.

l User Priority is determined by the Allocation Retention Priority (ARP), as listed in the following table.





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Table 4-1 Mapping of ARP to user priority

ARP 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

User priority Error 1 1 1 1 1 2 2 2 2 2 3 3 3 3 3

The traffic class, user priority, and THP determine only one SPI. The default mapping is described in the following table, where user priority 1 corresponds to Gold, 2 corresponds to Silver, and 3 corresponds to Copper.

Table 4-2 Default mapping of traffic class, user priority, and THP to SPI

Traffic Class User Priority THP SPI

SRB signaling No ARP None 15

IMS signaling No ARP None 14

1 None 13

2 None 13

Conversational (VoIP)

3 None 13

1 None 12

2 None 11

Streaming

3 None 11

1 1 10

1 2 9

1 3 to 15 8

2 1 7

2 2 6

2 3 to 15 5

3 1 4

3 2 3

Interactive

3 3 to 15 2

1 None 8

2 None 5

Background

3 None 2

SPI 0 and SPI 1 are not used.




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Issue 02 (2008-07-30)

Table 4-3 Default setting of algorithm based on SPI

SPI

CQI Adjust Algorithm Switch

Residual Bler Target

Max Retransmission Count

EPF Schedule Algorithm Switch

Flow Control Algorithm Switch

Weight of SPI

15 NO_CQI_ADJ NA 4 DS_PQ_SCHEDULE FLOW_CONTRL_FREE

100%

14 NO_CQI_ADJ NA 4 DS_PQ_SCHEDULE FLOW_CONTRL_FREE

100%

13 NO_CQI_ADJ 7 2 DS_URGENT_SCHEDULE

FLOW_CONTRL_FREE

100%

12 NO_CQI_ADJ NA 4 TS_SCHEDULE FLOW_CONTRL_DYNAMIC

100%


90%


100%


100%


100%


90%


90%


90%


80%


80%


80%





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4.2 HSDPA Flow Control in NodeB 4.2.1 Overview of NodeB HSDPA Flow Control

HSDPA Flow control is a process used to control HSDPA data flow from RNC MAC-d to NodeB MAC-hs according to Iub bandwidth and air interface bandwidth.

After HSDPA is introduced, users’ rate on air and on Iub is not consistent. It is necessary to adjust rate on Iub according to its rate on air.

The algorithm of NodeB HSDPA flow control is implemented through the 4.2.2 Signaling of HSDPA Flow Control. The NodeB allocates the capacity for each MAC-hs queue, and the RNC limits the downlink rate of each MAC-hs queue according to the allocated capacity.

The allocation process can be triggered by the capacity allocation request from RNC or from NodeB flow control algorithm.

Figure 4-3 Structure of flow control algorithm

NodeB and RNC can provide flow control functions. In NodeB, there are two types of flow control policies.

l Flow control free l Dynamic flow control

Dynamic flow control has three methods.

l No shaping l Shaping without adaptive Iub bandwidth. l Shaping with adaptive Iub bandwidth

4.2.2 Signaling of HSDPA Flow Control The signaling of HSDPA flow control is implemented through capacity request and allocation.

The following figure shows the signaling procedure for HSDPA capacity request and allocation.




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Figure 4-4 Signaling procedure for HSDPA capacity request and allocation

The signaling procedure is as follows:

l The CRNC sends an HS-DSCH Capacity Request to the NodeB, when some RLC PDUs are pending in the RLC entity and the credits (indicated in the latest HS-DSCH Capacity Allocation message) are used up. If there is no RLC PDU but the allocated capacity is greater than zero, the RNC also sends a Capacity Request to the NodeB, indicating that the NodeB can stop the capacity allocation.

l The NodeB sends an HS-DSCH Capacity Allocation message to the CRNC as the response to the HS-DSCH capacity request or to the requirement of the Iub HSDPA flow control algorithm.

The following figure shows the structure of the capacity request frame. The frame includes the queue priority and the data buffer size at the RNC RLC layer.

Figure 4-5 Structure of the capacity request frame

The following figure shows the structure of the capacity allocation frame.





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Figure 4-6 Structure of the capacity allocation frame

In the HS-DSCH Interval, the user can send a maximum number of HS-DSCH Credits MAC-d PDUs. The PDU size is limited by Maximum MAC-d PDU Length. The user can repeat the HS-DSCH Interval in the period defined by HS-DSCH repetition period.

l CmCH-PI: Scheduling Priority Indicator (SPI) of the queue. l HS-DSCH Interval: time interval during which the HS-DSCH Credits granted in the

HS-DSCH CAPACITY ALLOCATION control frame can be used. l HS-DSCH Credits: number of MAC-d PDUs that a CRNC can transmit during an

HS-DSCH Interval granted in the HS-DSCH CAPACITY ALLOCATION control frame. l Maximum MAC-d PDU Length: maximum PDU size among the MAC-d PDU sizes

configured in the NBAP messages. l HS-DSCH repetition period: number of subsequent intervals during which the HS-DSCH

Credits IE granted in the HS-DSCH CAPACITY ALLOCATION control frame can be used and the value 0 means that there is no limit to the repetition period.

4.2.3 Flow Control Policies Generally, the NodeB allocating the capacity to a MAC-hs queue considers the output rate on the Uu interface and Iub available bandwidth. For different QoS requirements, the NodeB uses different flow control policies, namely, flow control free and dynamic flow control.

The flow control policies are based on SPI and are configured through the Flow Control Algorithm Switch parameter. For details of recommended policy of flow control based on SPI, refer to 4.1.2 QoS Management of Services Mapped on HSDPA.

Flow Control Free Policy After the HS-DSCH bearer is set up, the NodeB sends a capacity allocation message to the RNC, indicating that the DL traffic of the new MAC-hs queue is not limited and the RNC MAC-d can send data as much as required. The allocation keeps unchanged for the service.




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The policy of no flow control policy is applied only to VoIP, IMS, and SRB, for these services are delay sensitive and have a relative low rate.

Dynamic Flow Control Policy Dynamic flow control is mainly applied to MAC-hs queues of BE service, for theses services are not delay sensitive, the rate varies in a wide range, and will reach a high rate during a burst.

Dynamic flow control is also applied to MAC-hs queues of streaming service, for streaming service has a relative high rate and may result in congestion on Uu.

This section mainly describes the method of shaping with adaptive Iub bandwidth of dynamic flow control policy. Other two methods are similar to shaping with adaptive Iub bandwidth, except that the functions of shaping or Iub adaptive bandwidth is ignored.

Dynamic flow control process of Shaping with adaptive Iub bandwidth is as follows:

Step 1 The congestion status of the transport network is reflected to NodeB through DRT and FSN. The NodeB adaptively adjusts the Iub bandwidth available for HSDPA based on the congestion detection.

Step 2 Depending on the available bandwidth and rate on air interface, the NodeB allocates bandwidth to HSDPA users and performs traffic shaping (Iub shaping) to avoid congestion and packet loss over the Iub interface.

Step 3 The RNC limits the flow of HS-DSCH data frames for each MAC-hs queue according to the HS-DSCH capacity allocation.

----End

Figure 4-7 Dynamic flow control algorithm structure





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Dynamic flow control policy consists of the following modules:

l Adaptive capacity allocation NodeB adaptively allocates capacity to an MAC-hs queue based on its rate on air interface. Capacity means how much data RNC can send to NodeB in an interval.

l Congestion control on Iub The total flow of all the MAC-hs queues should not exceed the available Iub bandwidth to avoid congestion on Iub. RNC provides the function of backpressure to avoid Iub congestion. For details, see Transmission Resource Management Description. NodeB provides the following functions to avoid Iub congestion: − Adaptive adjustment of Iub bandwidth

NodeB periodically detects Iub congestion and adaptively adjusts the available Iub bandwidth according to the Iub state.

− Iub shaping Iub shaping is used to allocate Iub bandwidth to every MAC-hs queue based on the available Iub bandwidth and ensure the total flow of the queues does not exceed the available Iub bandwidth. Thus, congestion control is achieved on the Iub interface, which increases the bandwidth usage and avoids overload.

The following description is only for NodeB version: V100R010C01B050

Dynamic flow control policy is configured through the Hsdpa Switch.

l If the switch is set to STATIC_BW_SHAPING, based on the configured Iub bandwidth and the bandwidth occupied by R99 users, traffic is allocated to HSDPA users when the physical bandwidth restriction is taken into account.

l If the switch is set to DYNAMIC_BW_SHAPING, according to the flow control of STATIC_BW_SHAPING, traffic is allocated to HSDPA users when the delay and packet loss on the Iub interface are taken into account. The RNC use the R6 switch to perform this function. It is recommended that the RNC in compliance with R6 should perform this function.

l If the switch is set to NO_BW_SHAPING, the NodeB does not allocate bandwidth according to the configuration or delay on the Iub interface. The RNC allocates the bandwidth according to the bandwidth on the Uu interface reported by the NodeB. To perform this function, the reverse flow control switch must be enabled by the RNC. The link is not congested when the delay is lower than this threshold. The link is not congested when frame loss ratio is no higher than this threshold.

l If the switch is set to BW_SHAPING_ONOFF_TOGGLE, if BW_SHAPING_ONOFF_TOGGLE is selected, the system automatically selects DYNAMIC_BW_SHAPING or NO_BW_SHAPING on the basis of the NodeB congestion detection mechanism. In other words, DYNAMIC_BW_SHAPING is selected when congestion is detected; NO_BW_SHAPING is selected when there is no congestion within a specific time.

BW_SHAPING_ONOFF_TOGGLE, DYNAMIC_BW_SHAPING, and NO_BW_SHAPING are flow control strategies applied at the NodeB part.

The following description is only for NodeB version:

Dynamic flow control policy is configured through the Hsdpa Switch.




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l If the switch is set to AUTO_ADJUST_FLOW_CTRL, the NodeB performs adaptive capacity allocation, Iub shaping and adaptive adjustment of Iub bandwidth. − When the Iub resource is the bottleneck, the algorithm performs capacity allocation

based on the bit rate on the Uu interface and the Iub shaping of dynamic flow control queues. Thus, the algorithm can meet the requirements for QoS and differentiated services, as described above.

− When the congestion on the Iub interface is invisible for the NodeB, the algorithm performs capacity allocation based on the bit rate on the Uu interface.

l If the switch is set to NO_FLOW_CONTROL, the NodeB performs adaptive capacity allocation, and does not perform Iub shaping and adaptive adjustment of Iub bandwidth. This setting is used when the congestion on the Iub interface is invisible for the NodeB, for example, when the congestion on the Iub interface is controlled by the RNC back pressure algorithm.

l If the switch is set to SIMPLE_FLOW_CTRL, the NodeB performs adaptive capacity allocation and Iub shaping, and does not perform adaptive adjustment of Iub bandwidth Some Iub bandwidth should be reserved for HSDPA users. This setting is used mainly for testing the algorithm during the design phase.

4.2.4 Adaptive Capacity Allocation Based on Uu Rate NodeB adaptively allocates capacity to an MAC-hs queue based on its rate on air interface (Uu).

The Uu interface transmission rate of the MAC-hs queue varies dynamically with several factors, such as the channel quality of the UE and activities of other users in the system.

It makes sense to keep the queue occupancy in a reasonable level in order to reduce data transmission delay, L2 layer signal delay, and discarding as the result of priority queue congestion or reset during handover. In this sense, the functionality is called capacity allocation adaptive to Uu interface bit rate, where capacity allocation for each priority queue is based on the Uu interface bit rate and the buffer occupancy level.

The Iub bandwidth allocation is based only on the rate of each queue on the Uu interface.

l If there is not enough data in the queue, a wide bandwidth is allocated. l If there is enough data in the queue, the bandwidth that is close to the rate on the Uu

interface is allocated. l If there is too much data in the queue, a narrow bandwidth or no bandwidth is allocated.

Whether there is enough data in the queue is judged by the time to send all the data in the priority queue with the current Uu rate.

4.2.5 Iub Shaping The allocation of the available Iub bandwidth to the MAC-hs queues is called Iub shaping. The available Iub bandwidth is from the algorithm of Adaptive Adjustment of Available HSDPA Bandwidth. Iub shaping ensures that the total flow of the queues does not exceed the available Iub bandwidth.

l If the resource on the Uu interface is the bottleneck, the algorithm allocates the Iub bandwidth to MAC-hs queue based rate on the Uu interface. The rate on the Uu interface is from Adaptive Capacity Allocation Based on Uu Rate.

l If the resource on the Iub interface is the bottleneck, the bandwidth allocation is based on the rate on the Uu interface and the available Iub bandwidth.





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− The algorithm considers the following factors of the MAC-hs queues: the bit rate allocated by Adaptive Capacity Allocation Based on Uu Rate, NodeB buffer occupancy, RNC buffer occupancy, and the bottleneck bandwidth available for HSDPA on the Iub interface from Adaptive Adjustment of Available HSDPA Bandwidth.

− First, Iub resource for GBR is allocated. That is, the algorithm first considers the basic requirements for guaranteeing the user experience.

− Then, the algorithm considers the requirement for user differentiation. For all the users in the cell, the scheduler intends to allocate the Iub resource in proportion to their Weight of SPI, which is based on user priorities, eg. gold, silver and copper.

User priority differentiation is implemented when Iub is the bottleneck. The gold, silver, and copper users obtain the resources in proportion to their priority weight factors (Weight of SPI). In addition, the resources necessary for guaranteeing the GBR must be allocated first before the resource allocation based on the proportion.

l For example, assume that Iub is the bottleneck, gold, silver and copper users are using FTP service simultaneously. Then the Iub throughputs of gold, silver and copper users are in proportion to the ratio of their SPI weights.

l For another example, assume that the silver user is using HTTP service, the gold and the copper user are using FTP service, and the silver user is reading the HTTP page. Then the gold and copper users share the Iub resource and the Iub throughput of the gold and copper users are in proportion to the ratio of their SPI weight.

4.2.6 Adaptive Adjustment of Available HSDPA Bandwidth Because the NodeB dynamic bandwidth allocation is based on the service statistics, the dynamic bandwidth allocation does not reflects the real-time bandwidth occupancy and the transport network quality. So it is necessary for NodeB to dynamically adjust the available HSDPA bandwidth when the traffic throughput changes or the transport network quality changes.

Adaptive adjustment of Iub bandwidth available for HSDPA is a part of the mechanism to control the congestion on Iub. The algorithm detects the Iub congestion and adjusts the available Iub bandwidth based on the detection result.

The adaptive adjustment of Iub bandwidth available for HSDPA takes effect only when the Hsdpa Switch parameter is set to DYNAMIC_BW_SHAPING or is set to BW_SHAPING_ONOFF_TOGGLE when congestion is detected (only for NodeB version: V100R010C01B050).

The adaptive adjustment of Iub bandwidth available for HSDPA takes effect only when the Hsdpa Switch parameter is set to AUTO_ADJUST_FLOW_CTRL (only for NodeB version: V200R010C01B041).

The output of the algorithm is an input of HSDPA flow control algorithm.

Detection of Iub Congestion The transmission delay is detected through DRT and frame loss is detected through FSN. FSN and DRT are taken from RNC to NodeB in HS-DSCH frame.

The algorithm periodically measures the congestion state based on transmission delay and frame loss.

l Frame loss is calculated as follows:




HSDPA Description


Issue 02 (2008-07-30)

Assume that for each MAC-d flow the HS-DSCH data frame must be delivered to the MAC-hs layer in FSN sequence. If the frames are not in sequence, the frames are lost. Then the number of lost frames is counted and the frame loss ratio at the Iub level in a specific time window is calculated.

l Delay buildup is calculated as follows: The HS-DSCH data frame transmission delay is the interval from the time when HS-DSCH data frame is generated in the RNC (identified as DRT) to the time when the frame arrives at the NodeB MAC-hs layer, including the buffer time in Iub Transport Network Layer (TNL). The delay buildup is the transmission delay increment comparing the sample delay with the reference one obtained when Iub is free of congestion, as shown in Figure 4-8.

Figure 4-8 Calculating delay built-up

Periodically the Iub congestion state is differentiated into three levels.

l Congestion due to delay buildup means that the delay buildup is larger than the Time Delay. Time Delay: is used to determine whether the Iub interface is congested because of delay buildup. By default, this threshold is set to 20 ms. It can be adjusted on the basis of the delay jitter allowed on the transport network. Generally, the threshold is set to the allowed delay jitter plus several milliseconds. If the threshold is too high, the transmission on the Iub interface will be much delayed when the Iub interface is the bottleneck. If the threshold is too low, the Iub interface will be regarded as congested by mistake. Thus, the transmission resource cannot be fully utilized.

l Congestion due to frame loss that means the frame loss ratio is greater than the Discard Rate. Otherwise frame loss may be caused by an Iub bit error. Discard Rate: is used to determine whether the Iub interface is congested because of frame loss. Generally, frame losses due to bit error are less than those due to congestion. By default, the threshold is set to 5%. It can be adjusted on the basis of transport network quality. The HS-DSCH frame error rate on the Iub interface within 300 ms can be a reference. If the threshold is too high, the congestion on the Iub interface cannot be alleviated in time. If the threshold is too low, the Iub interface will be regarded as congested in the case of frame loss due to bit error. Thus, the Iub bandwidth cannot be fully utilized.

l Congestion released means that there is no congestion due to delay buildup and no congestion due to frame loss.

The Time Delay and Discard Rate parameters can be set on NodeB LMT.





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Adjustment of Available Iub bandwidth The algorithm actively adjusts the available Iub bandwidth based on the congestion detection.

l If the Iub is in the congestion due to delay, the Iub bandwidth available for HSDPA is decreased by a step in direct proportion to the delay buildup.

l If the Iub is in the congestion due to frame loss, the Iub bandwidth available for HSDPA is decreased by a big step regardless of the delay buildup.

l If the Iub is in the congestion released, the Iub bandwidth available for HSDPA is increased by a smaller step, applying the strategy of increasing slowly, yet decreasing fast.

l In a time window of tens of seconds, if consecutive "congestion released" is detected, the Iub resource is identified as not the bottleneck. In this case, Iub bandwidth available for HSDPA is equal to the bandwidth of Iub port minus the bandwidth of R99 services and flow control free services.

4.3 HSDPA MAC-hs Scheduling One of the most important characters of HSDPA is that the HS-DSCH channel is a shared channel among all HS-DSCH users in a cell. Each user is possible to be scheduled in every 2 ms TTI. The resource competition happens among the HSDPA users when the air interface resources available for HS-DSCH are limited. The MAC-hs scheduling algorithm is introduced to select MAC-hs queues to be scheduled in each TTI to achieve considerable cell throughput capability and to satisfy user experience.

MAX C/I, Round Robin (RR), and Proportional Fair (PF) are the most popular scheduling algorithms in industry. The scheduling principles of these three algorithms are described in the following table.

Table 4-4 HSDPA scheduling algorithms

Algorithm

Factor Considered in Algorithm

Scheduling Principle

MAX C/I

CQI To select users according to the CQI value in descending order. The radio channel quality is the only factor considered in this algorithm and therefore the fairness among users cannot be guaranteed.

RR Waiting time of data buffered in the MAC-hs priority queue

To select users according to the waiting time of data buffered in the MAC-hs priority queue in descending order. The waiting time is the only factor considered in this algorithm and therefore the fairness among users can be guaranteed but the cell capacity degrades because the channel quality is not taken into account.

PF CQI, Average data rate of the MAC-hs priority queue

To select users according to the value of R/r in descending order, where R is the maximum data rate corresponding to the CQI, and r is the average data rate of the MAC-hs priority queue. The PF scheduler uses the variation in the radio channel qualities of individual users (for example, multi-user diversity) and provides the user with an




HSDPA Description


Issue 02 (2008-07-30)

Algorithm

Factor Considered in Algorithm

Scheduling Principle

average throughput proportional to its average CQI. This algorithm is a tradeoff between cell capacity and fairness among users.

When the HS-DSCH carries only the BE service, the PF scheduling algorithm can make a tradeoff between user equity and cell throughput. When the HS-DSCH carries more types of services, such as VoIP, streaming, SRB, and IMS, the HSDPA scheduling algorithm needs to guarantee the QoS. The reason is that such services have high requirements for delay or GBR. Based on the PF, the EPF algorithm is designed to guarantee the QoS of the following services:

l SRB and IMS have high requirements for service connection delay and handover delay. In addition, the average traffic volume and the consumption of the Uu interface are low. Therefore, the algorithm always selects the MAC-hs queues of SRB and IMS first.

l The VoIP service is highly delay sensitive. The maximum delay of MAC-d PDUs in a queue is specified by the discard timer of the MAC-hs queue. The scheduler needs to send out the MAC-d PDUs before the discard timer expires. The discard timer is usually shorter than 100 ms. Therefore, the scheduler has little chance of considering the channel quality. The scheduler always selects VoIP services after scheduling SRB and IMS services. Among MAC-hs queues of VoIP, the selection is based on both delay and channel quality.

l The streaming service is usually the CBR (Constant Bit Rate) streaming service. If the rate of this service is not lower than the GBR, the user can obtain good experience. Therefore, the scheduler needs to guarantee the GBR. When the average rate of the streaming service is lower than the GBR, the queues of the streaming service are selected first after SRB, IMS, and VoIP. Among the MAC-hs queues of the streaming service, the selection is based on PF.

l The BE service is allocated with the remaining resource after the resource requirements of the SRB, IMS, VoIP, and streaming services are met. Among the MAC-hs queues of the BE service, the selection is based on PF. In addition, the resource allocation complies with the following rules. Firstly, the GBR should be guaranteed first. Secondly, the algorithm considers the requirement for user differentiation. For all the users in the cell, the scheduler intends to allocate the radio resource in proportion to their Weight of SPI, which is based on user priorities, eg. gold, silver and copper. For example, assuming that radio resource is the bottleneck, gold , silver and copper users of same channel quality are using FTP service simultaneously, then the Uu throughputs of gold, silver and copper users are in proportion to the ratio of their SPI weights. For another example, assuming that the silver user is using HTTP service, the gold and copper user are using FTP service, and the silver user are reading the HTTP page, then the gold and copper users share the radio resource, and the Uu throughput of the gold and copper users are in proportion to the ratio of their SPI weight.

In a network, some UEs may be in a poor radio environment. More cell resources are used to ensure the GBR of these UEs, and consequently, quite few cell resources are available for other UEs. To avoid this problem, the resource limiting function is used. This function can be enabled through the parameter Resource Limiting Switch, which can be set on the NodeB LMT.

If Scheduling Method is set to EPF and Resource Limiting Switch is set to OPEN, the resource limiting function is enabled.





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The parameter that specifies the switch for resource limiting is shown as follows:

Resource limiting ratio is fixed according to GBR. The maximum ratio of the resource that can be used by GBR users is shown as follows:

GBR (bit/s) Maximum Ratio

8k 10%

16k 10%

32k 15%

64k 15%

128k 20%

256k 25%

384k 30%

After scheduling, HSDPA users will be allocated to different time and code. The following figure shows the time division and code division over the air interface for HSDPA users in one cell.

Figure 4-9 HSDPA scheduling based on time division and code division

Setting the Scheduling Algorithm The scheduling algorithm can be set through Scheduling Method on NodeB LMT. The settings are described as follows:

l PF: The service types of queues are not considered. All the queues in a cell are sequenced according to the PF values.

l RR: The service types of queues are not considered. All the queues in a cell are sequenced according to the RR values.

l MAXCI: The service types of queues are not considered. All the queues in a cell are sequenced according to the MAXCI values.

l EPF: The types of queues are considered. For each type of service, you can set a scheduling algorithm and a scheduling priority through the EPF Schedule Algorithm Switch parameter on NodeB LMT. The setting should be based on the mapping between service types and SPIs. For details of the EPF based on SPI, refer to Table 4-3.




HSDPA Description


Issue 02 (2008-07-30)

− DS_PQ_SCHEDULE: SRB/IMS scheduling policy. The SRB and IMS queues are scheduled before the VoIP, streaming and BE queues. DS means delay sensitive. PQ means priority queue.

− DS_URGENT_SCHEDULE: VoIP scheduling policy. The VoIP queues are scheduled before the streaming and BE queues but after the SRB and IMS queues.

− TS_SCHEDULE: streaming/BE scheduling policy. The streaming and BE queues are scheduled after the SRB, IMS, and VoIP queues. Among the streaming and BE queues, the resources for GBR are allocated first. The remaining resources are allocated as required by golden, silver, and copper users. TS means throughput sensitive.

4.4 HSDPA TFRC Selection l Overview of TFRC Selection l CQI Adjustment

4.4.1 Overview of TFRC Selection TFRC selection determines the transport block size, modulation type, HS-PDSCH codes, and HS-PDSCH transmission power. The UEs estimate and send CQI to the UTRAN to aid the TFRC selection.

The HSDPA resources over the Uu interface are allocated on a per cell basis. The scheduling algorithm arranges the MAC-hs queues in a cell in a certain order and then allocates resources to users in descending order of scheduling priority. The resource allocation takes the total available Uu resources, channel quality, and amount of data cached in the MAC-hs queue into consideration, with the output of the Transport Block Size (TBS), modulation mode, number of HS-PDSCH codes occupied, and allocated HS-PDSCH power of the HS-DSCH user within the current TTI.

The Transport Format Resource Combination (TFRC) selection is based on CQI-Max TBS mapping table, as shown in the following figure, which reflects the application of Adaptive Modulation and Coding (AMC) in HSDPA. For AMC, the UE measures the downlink channel quality and provides CQI feedback in the uplink, and the network adjusts the modulation and coding scheme for the UE based on the CQI in an adaptive manner. For example, when the channel quality is good, high order modulation can be applied to achieve higher throughput.





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Figure 4-10 TFRC selection process

The figure shows the process of TFRC selection.

1. Assuming that all the available Uu resources within the current Transmission Time Interval (TTI) are allocated to the UE, calculate the maximum Transport Block Size (TBSmax) based on the CQI from the UE and the reception capability of the UE. The calculation of TBSmax within the current TTI takes the following factors into consideration: − Available power of the HS-PDSCH

The HSDPA power allocated to the scheduled users within the current TTI and the HS-SCCH power allocated to the UE within the current TTI are excluded. In addition, the total transmit power for one UE within a TTI cannot exceed the value of the MAX POWER PER HS-USER parameter.

− Available codes of the HS-PDSCH − CQI from the UE

It is the output of the CQI adjustment algorithm within the current TTI. − UE capability

It denotes that the maximum number of HS-PDSCH code that the UE can use, the maximum size of the transport block that the UE can receive, and whether the UE supports 16QAM.




HSDPA Description


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2. If there is sufficient amount of data cached in the MAC-hs queue (TBSmax < Queue length), the data is scheduled for the UE as much as possible in the maximum format of TFRC, that is, TBS = TBSmax.

3. If there is insufficient amount of data cached in the queue (TBSmax > Queue length), the Uu resources necessary for the UE are allocated on the basis of the amount of data in the queue. Select the TFRC (power, code, and modulation mode) by searching the CQI-Max TBS mapping table and taking the amount of data cached in the queue into consideration. The search is based on the priority defined by the Resource Allocate Method parameter, that is, code preferable or power preferable. Outdoor cells usually have sufficient code resources but limited power resources. Therefore, for outdoor cells, codes take precedence over power during TFRC selection, so as to achieve resource efficiency in both code and power and to improve the cell throughput. For indoor cells, the priorities of codes and power are just the opposite, that is, power usually takes precedence over codes. The following figure shows an example of TBSmax searching.

Figure 4-11 Example of TFRC selection process and CQI-MaxTBS mapping

4. After TFRC is determined, the matched CQI of TBS in the CQI-MaxTBS mapping table is determined. This CQI is expressed as CQIused. Then, the transmit power of the HS-PDSCHs is calculated as follows: POWERHS-PDSCH = PCPICH + Γ – (CQIadjusted - CQIused). For details of the parameters and CQI adjustment, refer to 4.4.2 CQI Adjustment





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Within one TTI, the HS-PDSCH power and HS-SCCH power allocated to one UE cannot exceed the value of the MAX POWER PER HS-USER parameter. The limitation on the total transmit power of a single user is made for the following reason. In the initial deployment, only a few HSDPA users are included in a cell without high cell load expected. The function of HSDPA power limitation per user can limit the HSDPA cell load in this case. The HSDPA cell load is limited by the The Offset of HSPA Total Power parameter.

Setting the Resource Allocation Method The Resource Allocate Method parameter is set for the reason that the outdoor cells usually have sufficient code resources but limited power resources. Therefore, for outdoor cells, codes take precedence over power during TFRC selection, so as to achieve resource efficiency in both code and power and to improve the cell throughput. For indoor cells, the priorities of codes and power are just the opposite, that is, power usually takes precedence over codes.

4.4.2 CQI Adjustment The CQI indicates the number of bits that can be transmitted to the UE through certain HS-PDSCH power, a certain modulation method (QPSK or 16QAM), and a certain number of HS-PDSCH codes with an initial transmission BLER of 10%.

For the purpose of CQI reporting, the UE assumes the total received HS-PDSCH power as follows.

PHS-PDSCH = PCPICH + Γ + Δ

where,

l PCPICH is the power of the CPICH. l Δ is the reference power adjustment. For detailed information, see 3GPP TS 25.214. l Γ = Max(-6, Min(13, PCellMAX - PCPICH - MPOconstant))

− PCell-MAX - PCPICH = maximum transmit power of the cell - CPICH transmit power − MPOconstant represents HS-PDSCH MPO Constant and can be set on the RNC LMT.

CQI is a key input for user resource allocation. The accuracy of CQI influences Uu resource efficiency and user experience. For BE services, if the initial BLER is 10%, the residual BLER on the Uu interface is surely below 0.1% after retransmissions for more than three times, which is tolerable. For VoIP services, if the initial BLER is 10%, retransmissions for more than three times means that the delay of voice frames during end-to-end transmission increases by at least 36 ms, which negatively affects user experience. Therefore, it is necessary to set Max Retransmission Count and adjust the CQI based on the service type. The two algorithms available for CQI adjustment are as follows:

l IBLER-based CQI adjustment This algorithm enables the BLER of MAC-hs PDUs during initial transfer to be converged to the target IBLER. The target IBLER is dynamically adjusted on the basis of the actual cell load for the purpose of always achieving the optimal cell throughput. The algorithm adjusts the CQI based on the IBLER. In this case, with limited power, the algorithm adjusts the CQI on the assumption that the target is 10%, which can increase the throughput to an ideal level. If the power is not limited and load is light, the throughput is directly related to the target IBLER. The greater the target IBLER is, the higher the retransmission ratio at the physical layer, and the lower the valid throughput is. The target IBLER should be lowered to a degree.




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This method can be applied to streaming, BE, SRB, and IMS services. l RBLER-based CQI adjustment

This algorithm enables the BLER of MAC-hs PDUs after the initial transfer and the maximum number of retransmissions to be converged to the Residual Bler Target. This method can be applied to VoIP service.

Setting MPO If the value of HS-PDSCH MPO Constant is set properly, the probability of CQI being equal to 0 or 30 is very low, for example, 1% or lower. Otherwise, the parameter value should be adjusted. This parameter is set for the purpose that the CQI reported is within the range of 1 to 30.

Setting CQI Adjustment Algorithm The CQI adjustment algorithm, the target RBLER, and the maximum number of HARQ retransmissions are set on the NodeB side for each Scheduling Priority Indicator (SPI). In fact, these parameters are set on the basis of the service type. For details of the recommended configuration of CQI Adjust Algorithm Switch, Residual Bler Target, and Max Retransmission Count, refer to Table 4-3.

4.5 HSDPA Power Resource Management l Overview of Power Resource Management l Dynamic Power Resource Allocation

4.5.1 Overview of Power Resource Management The maximum cell transmit power is a constant. The DL power consists of the following parts:

l Power of DL HSPA physical channels, including the HS-PDSCH, HS-SCCH, E-AGCH, E-RGCH, and E-HICH The maximum available power can be set on the RNC LMT through parameter The Offset of HSPA Total Power.

l Power of common physical channels This type of power is reserved.

l Power of the DPCH

HSDPA power resource management addresses the following issues:

l The dynamic power allocation between HS-DSCH and R99 channels when HS-DSCH and R99 channels are on the same carrier frequencies.

l HS-DSCH power control: See HS-SCCH power control and HS-DPCCH power control in Power Control.

l HS-PDSCH power allocation: See 4.4.1 Overview of TFRC Selection.

4.5.2 Dynamic Power Resource Allocation The cell power resources are allocated dynamically between the DPCH and the DL HSPA physical channels, but the power resources are reserved for the common physical channels.





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After power resources are allocated to the DPCH, E-HICH, E-AGCH, and E-RGCH, the remaining resources are allocated to the HS-SCCH and HS-PDSCH. The power allocated to HSPA cannot exceed The Offset of HSPA Total Power.

Figure 4-12 Dynamic power resource allocation

As shown in the figure, the NodeB detects the R99 power occupancy every 2 ms to determine the power available for HSDPA. A certain Power Margin must be reserved to handle the power increase caused by R99 power control in each 2 ms.

4.6 HSDPA Code Resource Management l Overview of Code Resource Management l RNC-Controlled Static Allocation l RNC-Controlled Dynamic Allocation l NodeB-Controlled Dynamic Allocation

4.6.1 Overview of Code Resource Management The code resource consists of the following parts:

l Common channel and HS-SCCH channelization codes The number of HS-SCCH channelization codes in each TTI in the local cell determines the maximum number of users scheduled on the Uu interface. The number is determined by the traffic model of the cell. Generally, it is set to 4. Code Number for HS-SCCH is set on RNC LMT. The number of common channelization codes is specified when the cell is set up.

l HS-PDSCH channelization codes l DPCH channelization codes

The number of DPCH codes varies with the number of DCH users in the cell.

A key problem to be solved by code resource management is how to share code resource between DPCH and HS-PDSCH to increase the usage of the cell code resource.




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Three HS-PDSCH code allocation modes are described as follows:

l RNC-controlled static code allocation In the static code allocation, the HS-PDSCH codes are configured on the RNC LMT, and the allocated codes recorded on the RNC can be modified only through the Allocate Code Mode parameter.

l RNC-controlled dynamic code allocation It is is set through the Allocate Code Mode parameter on RNC LMT.

l NodeB-controlled dynamic code allocation It is set through the Dynamic Code Switch parameter.

In the RNC-controlled and NodeB-controlled dynamic code allocation, the HS-PDSCH code range is configured on the LMT. The UTRAN can automatically adjust the number of HS-PDSCH codes in real time based on the current cell codes used by R99 channels to maximize the usage.

The HS-PDSCH codes received by the UE in a TTI must be continuous. Therefore, the algorithm should try to reserve codes adjacent to the reserved HS-PDSCH codes during code allocation to the DL dedicated channels of the cell. Thus, the HS-PDSCH can have as many available codes as possible. When the state of the code resource used by R99 channels changed, the algorithm rearranges the allocated R99 codes so that more continuous SF16 codes are available for HSDPA.

NodeB-controlled dynamic allocation allows the NodeB to use the HS-PDSCH codes allocated by the RNC and also can dynamically allocate the idle codes of the current cell to the HS-PDSCH channel. It is more flexible to allocate the code for HS-PDSCH through the NodeB-controlled dynamic allocation than the RNC-controlled dynamic allocation. NodeB-controlled dynamic allocation can save the signaling traffic resource for code reconfiguration on the Iub interface, compared to the RNC-controlled dynamic allocation.

The following HS-PDSCH code allocation scheme is preferred:

l The RNC uses the static code allocation. The fixed number of reserved HS-PDSCH codes is specified by Code Number for HS-PDSCH. The NodeB uses the dynamic code allocation so that the HS-PDSCH codes can be increased.

l If the NodeB does not support the dynamic code allocation, you can enable the dynamic code allocation on the RNC side through the parameters Code Max Number for HS-PDSCH and Code Min Number for HS-PDSCH.

The HS-PDSCH code allocation mode can be set through Allocate Code Mode.

4.6.2 RNC-Controlled Static Code Allocation In static allocation, the RNC reserves codes for the HS-PDSCH. The DPCH, HS-SCCH, and common channels use the remaining codes.





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Figure 4-13 Static allocation

The Code Number for HS-PDSCH parameter can be set on the RNC LMT. The value of Code Number for HS-PDSCH is determined by the service model and the cell traffic model.

4.6.3 RNC-Controlled Dynamic Code Allocation In RNC-controlled dynamic allocation, the RNC adjusts the reserved HS-PDSCH codes according to the real-time usage status of the codes.

Figure 4-14 Dynamic allocation of the HS-PDSCH codes

A minimum number of codes, defined by the Code Min Number for HS-PDSCH parameter, are reserved for the HS-PDSCH in a cell. When the channelization codes in the cell are idle and adjacent to the reserved HS-PDSCH codes, the number of codes for the HS-PDSCH can be increased but cannot exceed the value of the Code Max Number for HS-PDSCH parameter. The difference codes between Code Max Number for HS-PDSCH and Code Min Number for HS-PDSCH are shared by the HS-PDSCH and the DPCH. The shared codes are allocated to the HS-PDSCH only when the DPCH does not use them. The dynamic allocation includes the increase and decrease of the codes for the HS-PDSCH.

Increasing the Codes Reserved for the HS-PDSCH The following figure shows the process for increasing the codes reserved for the HS-PDSCH. The solid dots represent the occupied codes and the circles represent the idle codes.




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Figure 4-15 Increasing the codes reserved for the HS-PDSCH

When the code consumption is reduced because of DCH RL deletion or RL reconfiguration (for example, SF is changed to a larger one), the RNC increases the codes reserved for the HS-PDSCH only when the following conditions are met:

l The shared code neighboring to the codes reserved for the HS-PDSCH is free. l After increasing the codes for the HS-DSCH, the SF of the remaining codes should be

equal to or smaller than the value of Cell LDR SF reserved threshold.

Cell LDR SF reserved threshold is used to reserve code resources for new admission and avoid code resource congestion. For details of Cell LDR SF reserved threshold, refer to Basic Congestion Triggering in Load Control.

Reducing the Codes Reserved for the HS-PDSCH The following figure shows the process of reducing the codes reserved for the HS-PDSCH. The solid dots represent the occupied codes and the circles represent the idle codes.

Figure 4-16 Reducing the codes reserved for the HS-PDSCH

When the re-allocation of code resources is triggered by DCH RL setup, RL addition, or RL reconfiguration (for example, SF is changed to a smaller one), the RNC will reallocate one of the shared codes reserved for the HS-PDSCH to the DPCH. After reallocating, the minimum SF of free codes should be lower than Cell LDR SF reserved threshold. The re-allocated code number should be the smallest one.





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4.6.4 NodeB-Controlled Dynamic Code Allocation NodeB-controlled dynamic allocation allows the NodeB to use the HS-PDSCH codes allocated by the RNC. The NodeB can dynamically allocate the idle codes of the current cell to the HS-PDSCH.

Figure 4-17 NodeB controlled dynamic allocation of the HS-PDSCH codes

The NodeB detects the SF16 codes that are not for the HS-PDSCH every 2 ms. If the codes or sub-codes are allocated by the RNC to the DCH or common channels, they are regarded as occupied. Otherwise, they are regarded as unoccupied. Therefore, the HS-PDSCH codes available for the HS-PDSCH include the codes allocated by the RNC and those unoccupied consecutive SF16 codes that are adjacent to the reserved HS-DSCH codes.

For example, in a cell HS-PDSCH, the RNC allocates SF16 codes numbered 11 to 15 to HS-PDSCH, SF16 codes numbered 0 to 5 to the DCH and common channels. Then, in this TTI, the HS-PDSCH can use SF16 codes numbered 6 to 15.

If the DCH codes allocated by the RNC are temporarily occupied by the HS-PDSCH before the setup of a radio link, the NBAP message is sent to the RNC, indicating that the radio link is set up successfully. Then, the DCH occupies the codes. The HS-PDSCH cannot use these codes until they are released by the DCH.

4.7 Other HSDPA Related Algorithms 4.7.1 HSDPA Cell Load Control

The UE can access an HSDPA cell only after it passes all of the following admission decisions:

l Admission decision based on power resources l Admission decision based on Iub resources l Admission decision based on UE quantity

For detailed information, see Load Control.

4.7.2 HSDPA Mobility Management HSDPA Mobility Management is applied in the mobility scenarios in which the HSDPA serving cell is involved.

For details, refer to Intra-Frequency Handover, Inter-Frequency Handover and Inter-RAT Handover Description.




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4.7.3 HSDPA Channel Switching HSDPA channel switching consists of channel switching between HS-DSCH and FACH and channel switching between HS-DSCH and DCH.

HSDPA channel switching refers to the following aspects:

l UE State Transition l Channel Switching Between HS-DSCH and FACH l Channel Switching Between HS-DSCH and DCH

UE State Transition After the HSDPA technology is introduced, a UE has a new RRC state, CELL_DCH (with HS-DSCH). The following figure shows the UE state transition.

Figure 4-18 UE state transition

The following table lists the UE state transition and channel switching.

Table 4-5 UE state transition and channel switching

UE State Transition Channel Switching

CELL_DCH (with HS-DSCH) <-> CELL_DCH HS-DSCH <-> DCH

CELL_DCH (with HS-DSCH) <-> CELL_FACH HS-DSCH <-> FACH

Channel Switching Between HS-DSCH and FACH To reduce the DPCH occupancy by the HSDPA UE, the RAN switches the transport channel from HS-DSCH to FACH. For details, refer to UE State Transition Algorithm in Rate Control Description.

Channel Switching Between HS-DSCH and DCH Channel switching from DCH to HS-DSCH can be triggered by mobility management, traffic volume, or timer. In comparison, channel switching from HS-DSCH to DCH can only be triggered by mobility management.

l Channel switching triggered by mobility management





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l For detailed information, see Intra-Frequency Handover and Inter-Frequency Handover. l Channel switching triggered by H Retry Timer Length. For detailed information, see

Mapping of Signaling and Traffic onto Transport Channels. l Channel switching triggered by traffic volume l The UE is rejected by the admission control algorithm when it attempts to access an

HSDPA cell. If the activity of the UE that performs data services increases and the RNC receives an event 4A report, the RAN tries to hand over the UE from the DCH to the HS-DSCH.

Channel switching from DCH or FACH to HS-DSCH needs to implement the process of HSDPA directed retry.

4.7.4 HSDPA TX Diversity The TX diversity mode of the HS-PDSCH can be set through the Hspdsch priority Tx diversity mode parameter on the RNC LMT.



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5 HSDPA Parameters

HSDPA Parameters provides information on the effective level and configuration of the parameters related to the feature.

Table 5-1 Parameters related to Inter-RAT Handover

Parameter Name Parameter ID Effective Level Configuration on ...

Allocate Code Mode AllocCodeMode Cell(ADD CELLHSDPA)

RNC

Cell LDR SF reserved threshold CellLdrSfResThd Cell(ADD CELLLDR) RNC

Code Max Number for HS-PDSCH HsPdschMaxCodeNum Cell(ADD

CELLHSDPA) RNC

Code Min Number for HS-PDSCH HsPdschMinCodeNum Cell(ADD

CELLHSDPA) RNC

Code Number for HS-PDSCH HsPdschCodeNum Cell(ADD CELLHSDPA)

RNC

Code Number for HS-SCCH HsScchCodeNum Cell(ADD CELLHSDPA)

RNC

H Retry Timer Length HRetryTimerLen RNC(SET COIFTIMER)

RNC

HS-PDSCH MPO Constant HsPdschMPOConstEnum

Cell(ADD CELLHSDPA)

RNC

Hspdsch priority Tx diversity mode

HspdschPrioTxDiversityMode

Cell(ADD CELLSETUP) RNC(ADD NRNCCELL)

RNC

Scheduling Priority Indicator

SPI

RNC(SET SPIFACTOR) RNC(SET SCHEDULEPRIOMAP)

RNC



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The Offset of HSPA Total Power HspaPower Cell(ADD

CELLHSDPA) RNC

Traffic Class TrafficClass -(SET USERGBR) RNC

Traffic Handling Priority THP

RNC(SET SCHEDULEPRIOMAP)

RNC

User Priority USERPRIORITY RNC(SET DEFAULTTRMMAP)

RNC

EPF Schedule Algorithm Switch EPFSA Cell(SET

MACHSSPIPARA) NodeB

Flow Control Algorithm Switch FCA Cell(SET MACHSSPIPARA) NodeB

CQI Adjust Algorithm Switch CQIADJA Cell(SET MACHSSPIPARA) NodeB

Max Retransmission Count MAXRETRANS Cell(SET MACHSSPIPARA) NodeB

Residual Bler Target RBLERTARGET Cell(SET MACHSSPIPARA) NodeB

Weight of SPI SPIWEIGHT Cell(SET MACHSSPIPARA) NodeB

Hsdpa Switch SWITCH

NodeB(SET HSDPAFLOWCTRLPARA)

NodeB

Discard Rate DR

NodeB(SET HSDPAFLOWCTRLPARA)

NodeB

Scheduling Method SM Cell(SET MACHSPARA) NodeB

Resource Limiting Switch RSCLMSW Cell(SET MACHSPARA) NodeB

EPF Schedule Algorithm Switch EPFSA Cell(SET

MACHSSPIPARA) NodeB

MAX POWER PER HS-USER MXPWRPHUSR Cell(SET MACHSPARA) NodeB

Resource Allocate Method RSCALLOCM Cell(SET MACHSPARA) NodeB

Max Retransmission Count MAXRETRANS Cell(SET MACHSSPIPARA) NodeB

Residual Bler Target RBLERTARGET Cell(SET MACHSSPIPARA) NodeB



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Power Margin PWRMGN Cell(SET MACHSPARA) NodeB

Dynamic Code Switch DYNCODESW Cell(SET MACHSPARA) NodeB

Time delay TD NodeB(SET HSDPAFLOWCTRLPARA)

NodeB



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6 HSDPA Reference Documents

HSDPA Reference Documents lists the reference documents related to HSDPA.

l 3GPP TS 25.101, "User Equipment (UE) radio transmission and reception (FDD)" l 3GPP TS 25.211, "Physical channels and mapping of transport channels onto physical

channels (FDD)" l 3GPP TS 25.212, "Multiplexing and channel coding (FDD)" l 3GPP TS 25.213, "Spreading and modulation (FDD)" l 3GPP TS 25.214, "Physical layer procedures (FDD)" l 3GPP TS 25.877, "High Speed Downlink Packet Access (HSDPA) - Iub/Iur Protocol

Aspects" l 3GPP TS 25.858, "Physical layer aspects of UTRA High Speed Downlink Packet

Access" l 3GPP TS 25.301, "Radio Interface Protocol Architecture" l 3GPP TS 25.302, "Services provided by the physical layer" l 3GPP TS 25.308, "UTRA High Speed Downlink Packet Access (HSPDA); Overall

description" l 3GPP TS 25.321, "Medium Access Control (MAC) protocol specification" l 3GPP TS 25.420, "UTRAN Iur interface general aspects and principles" l 3GPP TS 25.423, "UTRAN Iur interface RNSAP signaling" l 3GPP TS 25.425, "UTRAN Iur interface user plane protocols for CCH data flows" l 3GPP TS 25.430, "UTRAN Iub interface: general aspects and principles" l 3GPP TS 25.433, "UTRAN Iub interface NBAP signaling" l 3GPP TS 25.435, "UTRAN Iub interface user plane protocols for CCH data flows"



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