Contents 2

List of Figures and Tables 3

Abstract 4

1 Introduction 5 1.1 Comparative study between GSM network and UMTS 6 (3GPP release 99 and 3GPP release 4) 1.1.1 Modulation Methods and Data rates 6 1.1.2 Types of traffic 7 1.1.3 Network Architecture 7 2 High Speed Packet Access (HSPA) 11

2.1 High Speed Downlink Packet Access (HSDPA) 11 2.2 High Speed Uplink Packet Access (HSUPA) 14 2.3 3GPP Release 7 and 8 15 3 Development, Implementation and Architecture of LTE 16

3.0 LTE (Long Term Evolution) Overview 18

3.1 LTE Mobile devices and the LTE Uu interfaces 18

3.2 The e-NODE-B and the S1 and X2 Interfaces 18

3.3 The Mobility Management Entity (MNE) 20

3.4 The Serving Gateway (S-GW) and Gateway to Internet (PDN)

3.4.1 The Serving Gateway (S-GW) 21

3.4.2 The Gateway to the internet (PDN) 21 Conclusion 21

References 22

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List of Figures and Tables

Table 1 Data Rates for Mobile Communication Systems 13 Figure 1 GSM Network Architecture 9 Figure 2 UMTS Network Architecture Release 99 10 Figure 3 UMTS Network Architecture release 4 10 Figure 4 HSDPA Architecture overview 12 Figure 5 HSUPA Architecture overview 15 Figure 6 LTE Network Architecture overview 17

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Abstract This report describes the comparison between Global System for Mobile Communication (GSM) and Universal Mobile Telecommunication System (UMTS). High Speed Packet Access (HSPA), which includes HSDPA (High Speed Downlink Packet Access), HSUPA (High Speed Uplink Packet Access), and HSUPA+ were evaluated, with the analysis of its impact to network performance was also evaluated. And lastly, the development, implementation and overview of LTE (Long Term Evolution) were reviewed.

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1.0 Introduction

Mobile communications systems modernized the way people communicate, joining together communications and mobility. A lot has been achieved in a short time in the history of mobile wireless systems. Evolution of mobile wireless access technologies is about to reach its Fifth generation (5G). The cellular idea was introduced in the 1G technologies that made up the large-scale mobile wireless communication possible; it became available in the 1980s. 1G uses analog cellular technologies for communication and was later replaced by digital communication technology known as 2G in the 1990s, which significantly improved the quality of mobile network. It introduced services such as short messaging service (SMS) and lower speed data. GSM is generally known as 2G technologies. In addition to mobile network, Data and voice communication has been the main focus on 3G technologies and a converged network for both voice and data communication emerged. 3G requirements were specified by the ITU as part of the International Mobile Telephone 2000 (IMT-2000) project, for which digital networks had to provide 144 kbps of throughput at mobile speeds, 384 kbps at pedestrian speeds, and 2 Mbps in indoor environments. UMTS-HSPA and CDMA2000 EV-DO are the major 3G technologies. However, 3G Systems regardless of their enhanced features are still severely bandwidth-constrained, particularly for handling video communication traffic (Chakraborty , 2013). The Fourth generation (4G) which is considered as LTE (Long Term Evolution) provides access to a wide range of telecommunication services, including applications like wireless broadband access, Multimedia Messaging Service (MMS), video chat, mobile TV, HDTV content, Digital Video Broadcasting (DVB), minimal services like voice and data, and other services that utilize bandwidth according to the demands in multiuser environment (Sesia, Toufik and Baker, 2011).

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1.1 Comparative Review between GSM and UMTS Network 1.1.1

A. GSM GSM is the most widely used 2G air interfaces worldwide. Its strength lays in its widespread global penetration, which enables consumers to use their telephones when they travel. GSM phones have clip-on Subscriber Identity Module (SIM) cards. These cards contain a microchip that stores user identity and other information such as speed-dial lists. The SIM card encrypts voice and data before they are transmitted. GSM is the digital cellular standard that was originally decided on by European governments and was first deployed in 1992. GSM divides channels of 200 KHz spectrum into eight time slots. Seven of the time slots carry traffic and the eighth carries control signals. At first GSM was used exclusively for Voice communication but later, the control channel but soon it was also used to carry text messages called Short Message Service (SMS), which is otherwise known as text messaging. GSM uses a form of Time-Division Multiplexing (TDM). The GSM uses Gaussian Minimum Shift Keying (GMSK) modulation method.

B. UMTS Universal Mobile Telecommunications System (UTMS) is considered to be an effective and efficient 3G mobile communication systems in which there is an incorporated radio interface system. Additionally, it has been observed that the radio interface system is significantly based on Wideband Code Division Multiple Access (WCDMA). The radio frequencies that have been used in this system are of the order of 1900-2025 MHz as well as 2110-2200 MHz In this mobile system, a range of wireless multimedia communications is possible that are spread across the entire Internet protocol. It has been observed that this system allows a number of different mobile Internet users for the purpose of enabling them to access a variety of multimedia contents. These contents are available across the entire Internet and they are 5

considered to be arranged in a seamless fashion with data rates that are as much as up to 2 Mbps inside and 384 Kbps outside.

1.1.2 Types of Traffic GSM: It basically supports three types of traffic which includes: 1. Signaling: 16k, 32k, and 64k. 2. Voice/Fax 3. GSM Data: GPRS, EDGE, and Extended Data. UMTS: It has basically has four main classes of traffic types which includes: 1. Conversational class (voice, video telephony, video gaming). 2. Streaming class (multimedia, video on demand, webcast). 3. Interactive class (Web browsing, network gaming, database access).

4. Background class (Email, SMS, and Downloading).

1.1.3 Network Architecture

A. GSM

The GSM architecture can be divided into three categories, which includes: the Mobile Station (MS), the Base Station Subsystem (BSS), and the Network Subsystem. The mobile Station (MS): A mobile may be known as Mobile Equipment (ME), Mobile Terminal (MT) or Handset. The mobile Station usually contains the Subscriber Identity module (SIM). And they come in three sizes. Each device comes with an IMEI (international Mobile equipment Identity) and also each SIM has Unique Identification number known as IMSI (international Mobile Subscriber Identity). The Base Station subsystem (BSS): This consists of the Base Station Controller (BSC) and the Base Transceiver Station (BTS).

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Base Station Controller (BSC): This manages a group of BTSs which are usually connected together. The major function of the BSC is call maintenance. Base Transceiver Station (BTS): GSM uses a series of radio transmitters called BTSs to connect the mobile stations to the radio network.

The Network Subsystem: The network subsystem consists of: The mobile Switching Center (MSC), The Home Location Register (HLR), The Visitor Location Register (VLR), The Authentication center (AuC), and the Equipment Identity Register (EIR). The Equipment Identity Register (EIR): The EIR is a database that contains the list of all valid mobile station equipment within the network. The Mobile Switching Center (MSC): The MSC is responsible for functions relating to a mobile subscriber which includes registration, authentication, location updating, handovers and call routing. The Home Location Register (HLR): This is a database that is used for handling and managing mobile subscriber information. It stores the IMSI, IMEI, and the VLR address. The Visitor Location Register (VLR): This is database that contains the details of a Mobile Station such as information about last location, the power usage and details about other services. The Authentication Center (AUC): This is a database that holds the secret key used for the authentication and encryption of a mobile station within a network.

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Figure 1: GSM Network Architecture (Eberspacher et al., 2009)

B. UMTS As shown from the diagram, the key components of an UMTS system are: UTRAN (Universal Terrestrial Radio Access network), CN (Core network), UE (user Equipment), and NMS (Network Management Station), which is also the only vendor specific component. UTRAN: This is located between two open interfaces which are Uu and lu. It is the part that controls and manages the WCDMA radio resources. And it can also further handle handover. BSs: These are located between the interface Uu and lub in UTRAN architecture. Their main task is to establish physical implementation of the Uu and the lub interfaces by making use of protocol stack. RNC: This is located between the lub and lu interfaces, it acts as the switching and the controlling element in the UTRAN. UMTS CN: This is located between the access networks and the external networks. It is the basic medium for all communications services provided to the UMTS users. While the PS and the CS services are the two basic communication services provided by the Core network.

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Figure 2: UMTS Network Architecture Release 99 (Atayero et al., 2011)

Figure 3: UMTS Network Architecture Release 4 (Holma and Toskala, 2000).

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3GPP Release 99 and 3GPP Release 4 are the same in terms of the UTRAN (Universal Terrestrial Radio Access Network), with the UE and NMS. The only differences in 3GPP Release 4 and 3GPP Release 99 were on the CN (Core Network). Especially in 3GPP R4 in which the CN CS domain, MSC/VLR and GMSC have evolved into (G) MSC server and MGW. In the whole connection process is controlled by the server and the MGW acting as a switch. MGW contains the functionality of performing actual switching and network inter-working. And also in some instances, few MSC/GMSC servers can control numerous MGWs (Sauter, 2011; Abdullah et al., 2014). 2.0 High Speed Packet Access (HSPA) High Speed Packet Access (HSPA) is a broadband access that is an improvement to the WCDMA networks (FDD, and TDD) which is used in improving network performance. It is a combination of HighSpeed Downlink Packet Access or 3GPP Release 5, which was specified in 2002, and High Speed Uplink Packet Access (HSUPA), which is 3GPP Release 6, and specified in December 2004. HSPA is needed to increase the data rates of mobile networks, in comparison with fixed line broadband services. Therefore, HSPAs can support high data consuming and low latency applications such as Voice over Internet Protocol (VOIP). 2.1 High Speed Downlink Packet Access (HSDPA) HSDPA stands for High Speed Downlink Packet Access. It is referred to as a mobile telephony protocol. It is a new improved downlink packet data transfer structure for 3GPP systems. HSDPA is not just an ordinary transformation to a 3GPP specification, but an important upgrade that brings clear distinctive improvements and far higher data speeds than the normal 3G systems. HSDPA offers a technique by which the downlink capacity was improved within the current spectrum. With this, HSDPA downlink air interface is doubled or tripled. The present 3G system can only tolerate few maximum data rate per users at a particular time before the cell capacity runs out of downlink

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data from the spectrum. A normal mobile user consumes more downlink that uplink resources (Enan and Mustafa, 2014). Since the downlink consumes more payload data for most applications compared to the uplink. The HSDPA aims to expand downlink data capacity, and thus this possible bottleneck from the entire system. It helps to upgrade the entire system capacity as a whole by increasing the data rate allotted to a user (Holma and Toskala , 2006)

.

Figure 4: HSDPA Architecture (Abdullah et al., 2014)

Features of HSDPA

1. The HSDPA differs from the UMTS, which is observed by its ability to provide higherorder 16QAM modulation mode is used to improve spectral efficiency. 2. Both code division and time division are used in scheduling User Equipment (UEs). 3. The highest maximum transmission rate is the downlink. And also the rate reaches up to 14.4Mbit/s.

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4. The hybrid Automatic Repeat Request (HARQ) and Adaptive Modulation and Coding (AMC) technologies are applied at the physical layer. It means the factors such as modulation and a number of different coding formats have the ability to change themselves in relation to the differences in the channel conditions.

Advantages

1. HSDPA uses relatively shorter length of frame thereby displaying faster response to problems relating to radio channels. 2. HSDPA works best for applications that have unusual changeable and uneven requirement of bandwidth. 3. Some specific delays tend to occur in HSDPA, which may in turn assist novel applications such as interactive networked systems. 4. The HSDPA technology adds extra wideband downlink shared channel that is optimized for higher speed data transfer. HSDPA increases only the downlink throughput.

Table 1. Data Rates for Mobile Communication Systems (Holma and

Toskala, 2000).

System GSM GPRS EDGE 3G(R99) HSDPA

Typical Max. data rate (Kbit/s)

9.6 50 130 384 2048 (or more)

Theoretical Max. data rate (Kbit/s)

14.4 170 384 2048 14400

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2.2 High Speed Uplink Packet Access (HSUPA) High Speed Uplink Packet Access (HSUPA) is a release 6 Specification in 3GPP systems. And it is among the High Speed Packet Access (HSPA) family. It is more often known as technologies of 3.75G or Enhanced Uplink Dedicated Channel (E-DCH) by the technically mindful people, which is higher that most of the 3G technologies that are available. The main target of the HSUPA is to increase the data transfer speed in UMTS evolution technologies, thereby achieving a data speed of up to 5.8Mbps in the uplink. High Speed Uplink Packet Access (HSUPA) has the ability to improve the symmetric data rates such as emails in the mobile and video and gaming and data applications that vary from person to person. In addition to this, contrary to HSDPA, HSUPA has a dedicated channel and also, there is a series of channel for the purpose of traffic and signal so that all the uplink capabilities can be significantly improved. HSUPA can also be used in a number of different applications for the purpose of improving the DVD quality, live and heavy streaming and the ability to play real-time games in different modes readily and easily (Enan and Mustafa, 2014). Furthermore, if HSUPA is compared to the technology of dedicated channel, it may be found that the former has the ability to enable a higher user throughput.

Features of HSUPA

Transmission rate of about 5.8 Mbps. BPSK method of modulation. It supports Soft handover technique and Hybrid ARQ (HARQ). It supports fast packet scheduling with multicode transmission.

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Advantages

1. HSUPA significantly improves the data transmission rates, which aids in the fast transmission of data and retransmission of failed data, thereby enhancing the network performance of a system. 2. It supports the utilization of Soft hand over technique. The user receives control signals related to Node B cell scheduling from every radio link. After this, the transmission rate signals are combined together from different cells with the help of user terminal.

Figure 5: HSUPA Architecture (Abdullah et al., 2014)

2.3 3GPP Release 7 and 8 The Third Generation Partnership Program (3GPP) specifications has important enhancements in the downlink data rates and capacity in release 5 (HSDPA) which is also similar to the increase in uplink data rates and capacity in release 6 (HSUPA). 3GPP release 7 and release 8 are advancement to the High Speed Packet Access (HSPA) (3gpp, 2008).The 3GPP release 7 is known as HSPA

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evolution or HSPA+. While release 8 is categorized under the LTE specification. 3GPP release 7 supports the easy breakdown of network architecture. And the number of network elements is reduced as compared to release 6. And also the release 8 has further increased the radio capabilities and data rates thereby reducing the latency of the entire system as compared to the former technology releases. The LTE performance aim is to provide 2 to 4 times the performance of the HSPA release 6. 3GPP release 7 and 8 solutions for the HSPA evolution was merged in parallel together with the LTE development, and some aspects of the LTE work are reflected on the HSPA evolution as well (3gpp, 2008). .

Features of 3GPP Release 7 and Release 8

The challenges faced in earlier 3GPP specifications from release 99 to release 6 is the continuous reception and transmission when the mobile device. In former specifications the mobile device keeps transmitting the physical control channel even if there is no data. In release 7 and 8, the mobile terminal cuts off the CCT when there is no data channel transmission, allowing it to shut down the transmitter completely. In 3GPP release 7 and 8, the VOIP capacity is enhanced. A number of features have been introduced to 3GPP release 7 and 8 to improve the efficiency of low-bit rate, delay critical applications like Voice over IP. 3GPP 7 and 8 has far more flat and flexible architecture compared to lower 3GPP release. 3GPP release 6 has four network elements while, release 8 (LTE) has only two network elements.

3.0 LTE - Overview LTE, which stands for Long Term Evolution, is Third Generation Partnership Project (3GPP), which was proposed in November 2004. It is a system, which advanced from the Universal Mobile Telecommunication System (UMTS) and 15

also in turn from the Global System for Mobile Communications (GSM). Related specifications which were formally known as the evolved UMTS terrestrial radio access (E-UTRA) and evolved UMTS terrestrial radio access network (E-UTRAN). The First version of LTE was documented in Release 8 of the 3GPP specifications. The main aim of LTE is to offer a high data rate, low latency and packet optimized radio access technology supporting flexible bandwidth implementation. At the same time its network architecture has been designed with the aim to support packet-switched traffic with seamless mobility and great quality of service (Dahlman et al., 2011).

MME Serving-GW

PDN-GW

HSS

Internet

Mobile Device

eNode-BeNode-B

X2

S6

CP UPS1

S11

CP UP

S5

Figure 6: LTE Network Architecture overview (Sauter, 2011) 16

3.1 LTE Mobile devices and the LTE Uu interfaces In the LTE, just like in Universal Mobile Telecommunication Systems (UMTS), the mobile devices are called User Equipment (UE). In 3GPP Release 8, five different UE classes was defined and unlike in HSPA where devices support a wide range of different modulation and coding schemes because the standard evolved over time, all LTE UEs support the very fast 64-QAM (Quadrature Amplitude Modulation) in the downlink direction and antenna diversity. In the uplink direction, only the support of the slower but more reliable 16-QAM is required. LTE User Equipments (UEs) are categorized into five classes, 1-4 and these mobile devices under this category support MIMO transmission in the downlink direction. With this advanced transmission scheme, several data streams are transmitted on the same carrier frequency from multiple antennas from the base station to multiple antennas in the mobile device. LTE networks and devices use 2 2 MIMO, that is, two transmit and two receive antennas. In the future, 4 4 MIMO might be used with category 5 UEs class. Most LTE mobile devices also support other radio technologies such as GSM and UMTS. As a result, a typical LTE device today does not only support more LTE frequency bands but also supports those for the other radio technologies (Sauter, 2011).

3.2 The E-NODE-B and the S1 and X2 Interfaces In LTE specification, the Base station is usually known as eNode-B and it is a complex system. The name, which was gotten from UMTS base station which was called (Node-B) with the e meaning evolved. This changes was also done to UTRAN (Universal Mobile Telecommunications System Terrestrial Radio Access Network) which is now referred to as eUTRAN in LTE networks. 17

The eNode-B in LTE networks consists of three key elements which includes; The Antennas, radio modules that (modulate and demodulate all signals transmitted in the air interface and the digital modules that processes all signals transmitted and received on the air interface. In LTE networks, the eNode-B is not only responsible for the air interface but also focuses on management in general and scheduling air interface resources. The following are some of the other functions of eNode-B in LTE radio networks: For ensuring QoS such as ensuring latency and minimum bandwidth requirements for real-time users and maximum throughput for some applications. For load balancing between the different simultaneous radio network users. Mobility management For interference management, that is, to reduce the impact of its downlink transmissions on neighboring base stations in cell edge situations. The S1 as defined in LTE radio network serves two purposes which are: the eNode-B uses the S1 interface for interaction with the core network for its own purposes, i.e. to make itself known to the network, to send status and connection keep-alive information and for receiving configuration information from the core network (Atayero, 2011). And secondly, the S1 interface is used for transferring signaling messages that concern the users of the system. And it can also be used to maintain the connection, to organize a handover of the connection to another LTE, UMTS or GSM base station, in which user data packets can be forwarded between the two base stations involved in a handover process. The X2 interface is in the communication between two base stations in LTE radio networks. It has two major functions it performs, which are: The X2 interface with the core network are used in the

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implementation of handovers and secondly, it is used in the coordination of interferences (Atayero, 2011). .

3.3 The Mobility Management Entity (MNE) Since the eNode-Bs separately handles users and their radio bearers once they are established in LTE networks. There is need for a single point over which data flows between the user and the Internet, a centralized user database is required, which can be accessed from anywhere in the home network and also from networks abroad in case the user is roaming (Sauter, 2011). The network node responsible for all signaling exchanges between the base stations and the core network and between the users and the core network is the Mobility Management Entity (MME). In larger networks, there are usually many MMEs to manage the amount of signaling. Other functions of MMEs are stated below: Authentication. When a subscriber first attaches to the LTE network, the eNode-B communicates with the MME over the S1 interface and helps to exchange authentication information between the mobile device and the MME. Establishment of bearers. The MME itself is not directly involved in the exchange of user data packets between the mobile device and the Internet. It is responsible for selecting a gateway router to the Internet. Handover support. In case no X2 interface is available, the MME helps to forward the handover messages between the two eNode-Bs involved. Interworking with other radio networks. When a mobile device reaches the limit of the LTE coverage area, the eNode-B can decide to hand over the mobile device to a GSM or UMTS network or instruct it to perform a cell change to suitable cell. MME is largely in charge of instance and communication with the GSM or UMTS network components during this operation. 19

3.4 The Serving Gateway (S-GW) and Gateway to Internet

(PDN).

3.4.1 The Serving Gateway (S-GW) The S-GW is responsible for managing user data tunnels between the eNode-Bs in the radio network and the Packet Data Network Gateway (PDN-GW), which is the gateway router to the Internet. For example, a handover is performed by the eNode-B under the control of the MME and Serving Gateway (S-GW).

3.4.2 Gateway to the Internet (PDN) The third LTE core network node is Gateway to the Internet (PDN. In the LTE network, this node is the gateway to the Internet and some network operators also use it to interconnect to intranets of large companies over an encrypted tunnel to offer employees of those companies direct access to their private internal networks (Sauter, 2011). PDN also has the function of assigning IP addresses to LTE mobile devices. When a mobile device connects to the network after being switched on, the eNode-B connects to the MME, which then authenticates the subscriber and requests an IP address from the PDN-GW for the device (Sauter, 2011).

Conclusion In todays world Mobile communication is getting faster and speedy and it is the backbone of every business and day-to-day life. Mobile technologies have played a very vital role in rapid advancement and growth of technology over the past half-decade. With the rapid growth of user demands, and the limitations of some mobile communication technologies, it is expected that new technologies will eventually hit the market and are expected to become a platform capable of delivering 20

increased data rates, greater interoperability across communication protocols, user-friendly innovative and secure applications.

References

3GPP Standard, 2008. Ultra- Ultran Long Term Evolution (LTE) and 3GPP System Architecture Evolution (SAE). March. Abdullah, O., Enan, M., Babiker, A., and Mustafa, N., 2014. Comparative Study between UMTS, HSDPA and HSUPA. Journal of Electronics and Communication Engineering, 9(4), pp. 21-30. Atayero, A., Luka,k.,Orya, K., and Iruem,J, 2011. 3GPP Long Term Evolution: Architecture, Protocols, and Interface. International Journal of information and Communication technology Research (IJICT), November.1(7). Chakraborty, A., 2013. A study on Third Generation Mobile technology (3G) and Comparison Among all Generations of Mobile Communication. International Journal of Innovative Technology and Adaptive Management (IJITAM), November.1(2). Eberspacher, J., vogel, H., Bettstetter, C., and Hartmann, C., 2009. GSM Architecture, Protocols and Services. 3rd ed. Chichester, United kingdom: John Wiley & Sons, Ltd. Erik, D., Parkavali, S., and Skold, J, 2011. 4G LTE/LTE: Advanced for Mobile Broadband. 1st ed. United kingdom: Elsevier. Holma and Toskala, 2000. WCMDA for UMTS. Chichester, England: John Wiley & Sons, Ltd. Holma, H and Toskala, A, 2006. HSDPA/HSUPA For UMTS : High Speed Radio Access for Mobile Communications. West Sussex, United Kingdom: John Wiley & Sons, Ltd. 21

Kumar, A., Liu, Y., and Senguta, J, 2010. Evolution of Mobile Wireless Networks: 1G to 4G. International Journal of Electronics & Communication Technolgy (IJECT), December.1(1). Sauter, M, 2011. From GSM To LTE: An Introduction of Mobile Networks and Mobile Broadband. Second ed. West Sussex, United Kingdom: John Wiley & Sons, Ltd. Sesia, S., Toufik, I., and Baker, M., 2011. LTE- The UMTS Long Term Evolution From Theory to Practice. 2nd ed. West Sussex, United Kingdom.: John Wiley & Sons, Ltd.

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