Link Budget of Cdma2000 1xev-Do Wireless Internet Access System

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LINK BUDGET OF cdma2000 1xEV-DO WIRELESS INTERNET ACCESS SYSTEM

Peter J. Black and Qiang Wu

QUALCOMM Incorporated, 5775 Morehouse Drive, San Diego, CA 92121

Abstract - This paper presents the analysis and simulation

results for a 1xEV-DO link budget. The traditional fixed rateCDMA link budget calculation has been extended to includelink adaptation and multi-user diversity gains. The mainconclusion is that 1xEV-DO provides a link budgetadvantage over IS-95-A of approximately 10 dB on theforward link and 1.5 dB on the reverse link.

Keywords – Link budget, cell coverage, rate adaptation,multi-user diversity, 1xEV-DO, IS-856, cdma2000.

I. INTRODUCTION

The cdma2000 1xEV-DO standard, also known as IS-856[1], is developed to provide spectrally efficient packet dataservices for wide area wireless Internet access. Due to the

asymmetric characteristic of this type of services, theforward link is the more critical link. By utilizingtechnologies such as virtual soft handoff, rate control,hybrid-ARQ and multi-user diversity, the 1xEV-DO systemachieves a spectral efficiency of approximately1bit/chip/sector on the forward link for a mix of mobile/portable users [2]. An additional advantage of theefficient waveform designs is the improved link budget orcell coverage, which will be investigated in this paper.

A link budget determines the maximum allowable pathloss of a given communication link. For wireless systems, itis simply the difference between the transmitter EIRP andthe receiver sensitivity, plus receiver antenna gain and lessfade margin, building penetration loss and body (or cable)

loss (all in decibel scale).Given a certain transmitter power and antenna gain, oneobserves certain maximum radiation intensity. Thetransmitter EIRP is the effective input power to ahypothetical isotropic antenna that achieves such radiationintensity in any direction. It is a function of transmitterpower, transmitter antenna gain and cable (or body) loss. Inother words, the transmitter EIRP is calculated as follows,

Transmitter EIRP (dBm) =Transmitter Power (dBm) + Tx Antenna Gain (dBi) - Cable (or

Body) Loss (dB)

The receiver sensitivity denotes the minimum signal levelat the antenna connector required to close thecommunication link at a given data rate and under the worst-

case fading channel, i.e., Receiver Sensitivity (dBm) =

Thermal Noise (dBm/Hz) + (Ior/No)req(dB) + Bandwidth(dB-Hz)

It can also be expressed as, Receiver Sensitivity (dBm) =

Thermal Noise (dBm/Hz) + ( Eb/No)req(dB) + Data Rate(dB-Hz)

The required Ior/No or average Eb/No is a common

measure of modem efficiency, which will be discussed inthe following sections (Standard CDMA terms andconventions have been used, for definitions refer to [3]).

II. FORWARD TRAFFIC CHANNEL LINK BUDGETASSUMPTIONS

This section summarizes the assumptions and methodused to derive the required Ior/No to achieve a certainforward link user throughput for a given geometry and underworst-case fading conditions.

A. Geometry

A mobile at the edge of one base station's coverage is verylikely to be also covered by a neighboring base station. Assuch the model assumes 2-way soft handoff with equal pathloss from the two candidate serving base stations. The co-channel interference is represented by a third cell 6dB down.Therefore, the total noise and interference power spectrumdensity is No+1.25Ior. Total sector throughput is simulatedversus Ior/No based on the above geometry. Given that thetotal sector throughput assumes 100% of the available timeslots, the single user throughput is derived from scaling thesector throughput by the serving fraction for the user.

B. Forward Link User Throughput

For the IS-95-A Code Division Multiplex approach at thefixed data rate of 9.6kbps, the traffic channel power onaverage is typically not allowed to exceed –12.7dB of theBTS power (average traffic channel gain). The forward link budget calculation for IS-95-A assumes 2-way powercombined soft handoff, thus, the effective traffic channelpower normalized to a single serving sector is –9.7dB of theBTS power (equivalent to 10.72%). Assuming 30% of power dedicated to pilot, paging and sync channel overheadthis is equivalent to 15.3% of the available traffic channelpower. Given the 1xEV-DO forward traffic channel isvariable rate, time division multiplexed and uses selectiondiversity soft handoff, a fair link budget comparison wouldbe for the same average user throughput of 9.6kbps and withthe same serving fraction of the traffic channel time slots. Ina 1xEV-DO system, taking into account the control channeloverhead, 15.3% of the available traffic channel slots isequivalent to 14.3% of the total serving slots. All results arepresented as aggregate sector throughput, which assumes100% of serving slots are utilized, therefore the userthroughput is calculated as 14.3% of the sector throughput.

0-7803-7589-0/02/$17.00 ©2002 IEEE PIMRC 2002



C. Fading Channel

For the purpose of the link budget calculation, only theworst-case fading channel that corresponds to the highestrequired Ior/No is of interest. The following ITU channelmodels are simulated: Pedestrian A and B, Vehicular A, andRice [4].

D. Multi-user Diversity GainThe single user simulations assume 100% of the serving

time is dedicated to one user. An N user simulation, with allthe users at the same geometry, is also run to take intoaccount the multi-user diversity gain achieved throughpacket scheduling [2] – serving of users at local peaks inSINR subject to fairness criterion. In all cases sectorthroughput versus Ior/No is plotted. For a given userthroughput, the difference between the required Ior/No forthe single user case and the N user case indicates the gainachieved by multi-user diversity. The multi-user network simulation is limited to the case of N=4 users (The multi-user gain increases with the number of simultaneous activeusers. The link budget comparison assumes 14.3% or 1/7 of the serving slots. The choice of N=4 yields a conservativemulti-user gain estimate).

E. Rx Diversity Gain

For mobiles with dual receive antennas the receivediversity gain is included. An N dual-antenna usersimulation, with all the users at the same geometry, is run totake into account receive diversity gain. For a given userthroughput, the difference between the required Ior/No for Nsingle-antenna user case and the required Ior/No per antennafor N dual-antenna user case indicates the gain achieved byreceive diversity.

F. Example: Multi-user and Rx Diversity Gain

The forward link sector throughput vs. Ior/No for a singleuser with single antenna is shown in Fig. 2.1, for N=4 userswith single antenna is shown in Fig. 2.2, and for N=4 userswith dual antennas is shown in Fig. 2.3. The worst casefading condition occurs in the PedA 3km/hr channel forsingle user case and in the VehA 30km/hr channel for themulti-user case. The worst case is found from Figs. 2.1-2.3as the rightmost curve for a sector throughput of 67.1 kbps.This corresponds to a user throughput of 9.6 kbps assuminga 14.3% fraction of serving time. The correspondingrequired Ior/No per antenna are -5.0dB, -7.0dB and -11.6dBfor single user link, N-user network and N-user network with dual receive antennas, respectively. As a result, themulti-user diversity gain equals 2.0dB and the receive

diversity gain equals 4.6dB (excluding multi-user diversitygain).

III. FORWARD CONTROL CHANNEL LINK BUDGETASSUMPTIONS

Geometry: {Ior, Ior, 0.25Ior}, Single Antenna, 1 User

10

100

1000

-12 -10 -8 -6 -4 -2 0 2 4 6 8

Ior/No

S e c t o r T h r o u g h p u t ( k b p s )

channel 1 (PedA, 1 path, 3kmph)channel 2 (PedB, 3 paths, 10kmph)channel 3 (VehA, 2 paths, 30kmph)channel 4 (PedA, 1 path, 120kmph)channel 5 (Rice, K=10dB, 0.826kmph)

Fig. 2.1 Single User Link Simulations

Geometry: {Ior, Ior, 0.25Ior}, Single Antenna, 4 Users

10

100

1000

-12 -10 -8 -6 -4 -2 0 2 4 6 8

Ior/No



Fig. 2.2 N-user Network Simulations (N=4)

Geometry: {Ior, Ior, 0.25Ior}, Dual Antenna, 4 Users

10

100

1000

10000

-12 -10 -8 -6 -4 -2 0 2 4 6 8

Ior/No per antenna



Fig. 2.3 N-user Network Simulations with Dual ReceiveAntenna Diversity (N=4)

In this section, we derive the required Ior/No to ensure areliable Forward Control Channel transmitted at a fixed data



rate of 38.4kbps or 76.8kbps. The same geometry asspecified in Section 2 is used and a packet error rate of 2%is targeted under the worst case fading condition. Since theControl Channel is a broadcast channel the multi-userdiversity gain does not apply.

Figs. 3.1 and 3.2 show the Forward Control Channel PERversus Ior/No at 38.4kbps for single antenna case and dual

antenna case, respectively. Figs. 3.3 and 3.4 show theForward Control Channel PER versus Ior/No at 76.8kbps forsingle antenna case and dual antenna case, respectively. InFigs. 3.1 and 3.2, only the worst-case channels at 3km/hr areshown.

For 38.4kbps, the worst case occurs in PedA 3km/hr forsingle antenna case and PedB 3km/hr for dual antenna case.The required Ior/No’s are 4.0dB and -8.0dB, respectively.As a result, for the Control Channel transmitted at 38.4kbpsthe Rx diversity gain equals 12.0dB.

Since the assumed geometry sets a limit on Ior/Nt equal toIor/1.25Ior, the Control Channel transmitted at 76.8kbpscannot achieve a 2% PER for single antenna and the worstchannel condition of PedA 3km/hr. For the Control Channeloperating at 76.8kbps in the dual antenna case, the requiredIor/No for 2% PER is -4.5 dB under the worst-case channelof PedA 3km/hr.

For the single antenna case, given the worst case channelcondition and an Ior/No of 4.0 dB, the Control Channelachieves a 2% PER at 38.4kbps, and a 6% PER at 76.8kbps.

Geometry: {Ior, Ior, 0.25Ior}, Single Antenna, Fixed Rate at 38.4kbps

0.001

0.01

0.1

1

-10 -8 -6 -4 -2 0 2 4 6

Ior/No

P E R

PedA 3kmph

PedB 3kmph

Fig. 3.1 Single Receive Antenna, 38.4kbps

IV. REVERSE TRAFFIC CHANNEL LINK BUDGETASSUMPTIONS

In this section, we derive the required average Eb/No toensure reliable operation of the Reverse Traffic Channelunder 50% system load, worst-case fading channel, and a

target PER of 2%. A. Dual Receive Antennas

Dual receive antennas at the base station receiver isassumed. For the link budget calculation, the requiredaverage Eb/No per antenna is the parameter of interest.Therefore, in the following sections the average Eb/Norefers to the average Eb/No per antenna.

Geometry: {Ior, Ior, 0.25Ior}, Dual Antenna, Fixed Rate at 38.4kbps

0.001

0.01

0.1

1

-10 -8 -6 -4 -2 0 2 4

Ior/No per antenna

P E R

PedA 3kmph

PedB 3kmph

Fig. 3.2 Dual Receive Antenna, 38.4 kbps

Geometry: {Ior, Ior, 0.25Ior}, Single Antenna, Fixed Rate 76.8kbps

0.001

0.01

0.1

1

-10 -8 -6 -4 -2 0 2 4 6

Ior/No

P E R

PedA 3kmph

PedB 3kmph

120kmph 1pth

Fig. 3.3 Single Receive Antenna, 76.8kbps

Geometry: {Ior, Ior, 0.25Ior}, Dual Antenna, Fixed Rate at 76.8kbps

0.001

0.01

0.1

1

-10 -8 -6 -4 -2 0 2 4

Ior/No per antenna

P E R

PedA 3kmphPedB 3kmph120kmph 1pth

Fig. 3.4 Dual Receive Antenna, 76.8kbps

B. % Power for the Data ChannelThe Reverse Traffic Data Channel of the 1xEV-DO

system transmits at a fraction α of the total transmitterpower. For the purpose of link budget calculation, the datachannel Eb/No is scaled by 1/ α to obtain the total Eb/No.Such Eb/No is the ratio of the total energy (including pilot,



DRC and ACK) received per information bit to the thermalnoise power spectrum density.

C. System Load

The required Eb/No is obtained assuming no system load,which is defined by Io/(No+Io). The effective system load isincluded through a system load margin, which is calculated

by -10Log10 (1-system load). In IS-95-A link budgetcalculations it is customary to assume a 50% system load.

D. No Power Control

A link budget derives the maximum allowable path lossfor which link closure can occur. In this case it is assumedthat a mobile unit is transmitting at the maximum powerlevel, effectively disabling the effects of power control.

E. 2-way Soft Handoff

A mobile at the cell edge is very likely covered by aneighboring base station, in which case the 1xEV-DOsystem would place such a mobile in soft handoff. Since thereverse link employs selection diversity on a frame-by-

frame basis, it combats not only shadowing but also multi-path fading. A reconstructed frame in the switching center isin error only if both reverse link frames are in error. Thus,the required Eb/No is determined by noting where theproduct of the two reverse link PERs is at the specifiedoperating point. As an example, if the overall target PER is2%, each link can have 14% PER. This effect provides asignificant gain in slow speed conditions.

F. Differential Fade Margin

The 14% target PER calculation explicitly assumes thetwo soft handoff links are equally balanced. Such anassumption maximizes the selection diversity gain on thetwo multi-path fading processes. However, the standard

4.1dB selection soft handoff gain [5] for shadowing onlyguarantees the better link and implicitly allows a differentialbetween the links. As a result, the soft handoff gain isoverstated relative to the equal path required Eb/No. Thedifferential path loss can be included in the soft handoff gainby defining the outage criterion as the set of pairs of Eb/Nofor each link such that the product of the link PERs is equalto the target. For the worse case PedA curve shown in Fig.4.1 and given a 0.5 correlation between the shadowingprocess for each link, the required fade margin is increasedby 2.1dB. This reduction is referred to as the differentialfade margin.

Fig. 4.1 shows the Reverse Traffic Channel PER versuspilot Ec/Nt (or pilot Ec/No at no system load in which

situation Nt = No). The worst case occurs in the PedA3km/hr channel. In this case, the required pilot Ec/No is -22.5 dB. This assumes a 9.6 kbps link, a 14% PER, nopower control and no system load.We can derive the total Eb/No per antenna as:

++++

+= 101010

0

,

0

1010101log10RW

log10 ACKGain DRCGain DataGain

pcb

N E

N E

All the gains in the above equation define the relativepower levels of the corresponding channels to the pilotchannel. We will assume DataGain = 3.75 dB for 9.6kbps,DRCGain = -3.0 dB (with DRCLength = 4 slots under thesoft handoff geometry assumed) and ACKGain = 4.0 dB [2].Using these gain values and pilot Ec/No = -22.5 dB in theabove equation returns a total Eb/No = 6.6 dB, which is

required to achieve a 2% effective PER at the data rate of 9.6kbps under no system load.With careful selection of the data to pilot channel gains all

reverse link data rates achieve similar PER for the samevalue of pilot Ec/Nt and therefore Fig. 4.1 can be applied toall reverse link data rates. Table 4.1 shows the requiredtotal Eb/No for each reverse link data rate, assuming onceagain an unloaded system and a 2% PER.

As observed, higher data rates come with lower relativeoverhead of the Pilot, DRC and ACK Channels, and thusresult in lower required total Eb/No under the samerequired data channel Eb/No. In the case of 153.6kbps, thehigher Eb/No is due to the reduced coding gain provided bythe Rate 1/2 vs. the Rate 1/4 code used in all the lower rates.

−25 −24 −23 −22 −21 −20 −19 −18 −17 −16 −15

10−3

10−2

10−1

100

9.6 kbps, r=1/4, Traffic Gain = 3.75 dB, No Power Control, 2 RX Antennas

P E R

Avg. Pilot Ec/Nt per Antenna, dB

PED. A 3km/h, 10% PER =>−21.4dBPED. B 3km/h, 10% PER =>−21.8dBVEH. A 120km/h, 10% PER =>−24.1dBVEH. B 120km/h, 10% PER =>−23.6dB

Fig 4.1 Reverse Traffic Channel PER at fixed data rate of 9.6kps with power control off

Table 4.1 The required total Eb/No @ no system loadData Rate (bps) 9 ,600 19,200 38,400 76,800 153,600DataGain (dB) 3.75 6.75 9.75 13.25 18.5Required total

Eb/No perantenna (dB)

6.62 4.98 3.84 3.55 5.27

V. L INK BUDGET CALCULATION

The link budget for a 1xEV-DO system is derived andcompared with that of an IS-95-A system under thecondition of equal effective served rate. Since serviceproviders may want to deploy 1xEV-DO systems using thesame network plans as IS-95-A but on a separate carrierfrequency, it is also of interest to derive the 1xEV-DOforward user throughput under an IS-95-A link budget.



The Forward Traffic Channel and Control Channel in1xEV-DO find their counterparts in IS-95-A as the ForwardTraffic Channel and Paging Channel. In the following weshow the link budgets for both traffic channels and control(paging) channels for both systems.

A. Comparison between 1xEV-DO and IS-95-A Forward Traffic Channel Link Budgets

From Tables 5.1 and 5.2 we find that the 1xEV-DO link budget for the Forward Traffic channel is 147.7 dB for thesingle antenna case and 152.3 dB for the dual antenna case.This is derived assuming a 9.6 kbps user throughput, 14.3%serving fraction of time, and 90% probability of cell edgecoverage. The corresponding value for an IS-95 trafficchannel is found in Table 5.3 to be 138.2 dB, in which casewe again assume 90% edge coverage, 9.6 kbps, and aneffective traffic channel gain of –9.7 dB.

1xEV-DO provides approximately 10 dB link budget gainover IS-95-A on the forward link. Under the IS-95-A link budget (138.2 dB), a 1xEV-DO single receive antennaterminal would achieve a long-term average forward user

throughput of 32.2kbps or equivalently a short-term averageburst rate of 225kbps. The 1xEV-DO dual receive antennaterminals would achieve long-term average forward userthroughput of 70.8kbps or equivalent short-term burst rate of 495kbps.

B. Comparison between 1xEV-DO and IS-95-AControl/Paging Channel Link Budgets

From Table 5.3, we can conclude that with 20% of thetransmitter power allocated to the Paging Channel and a10% target PER, the IS-95-A Paging Channel link budget is134.2 dB, 4 dB lower than that of the IS-95-A ForwardTraffic Channel.

While for the 1xEV-DO Control Channel, under the IS-95-A Forward Traffic Channel link budget, 2% PER isensured at receiver for 38.4kpbs and 76.8kbps with dualreceive antenna diversity. With single receive antenna, forthe Control Channel transmitted at 38.4kbps and 76.8kbps, a3% PER and a 7% PER are ensured, respectively, under theIS-95-A Forward Traffic Channel link budget.

C. Comparison between 1xEV-DO and IS-95-A Reverse Link Budgets

From table 5.4, we conclude that for 90% cell edgecoverage and data rates 9.6kbps and 19.2kbps, the 1xEV-DO reverse link budgets are 135.3dB and 133.9dB,respectively. While for IS-95-A, for 90% cell edge coverageof the data rate at 9.6kpbs, the reverse link budget is 133.9dB. 1xEV-DO provides approximately 1.5 dB link budgetgain over IS-95-A on the reverse link.

The service providers can plan an 1xEV-DO network foradequate coverage of reverse link data rate at 19.2kpbs andstill achieve the same link budget as that of an IS-95-Anetwork which only has adequate coverage of reverse link data rate at 9.6kbps.

D. Fwd/Rev Average Burst Rate vs. Path Loss

Fig. 5.1 shows the 1xEV-DO forward link average burstrate and reverse link data rate achievable for 90% cell edgecoverage vs. path loss. For the forward link, single and dualreceive antenna cases are presented. For the reverse link,system load margins of 3dB and 5dB are shown. Whileplanning the networks, service providers can optimize thesystem load by trading off the reverse link capacity and cellcoverage. Based on Fig. 5.1, one can easily obtain themaximum path loss, based on the minimum required reverselink data rate, and then find the forward link average burstrate that can be achieved under that path loss. For example,if one wants to support at least 19.2kbps on the reverse link for 90% cell coverage under a system load margin of 5dB,the maximum allowable path loss is 131.9 dB. For the singlereceiver antenna case this corresponds to a forward link average burst rate over 260kbps, while for a dual receiverantenna case, it corresponds to a forward link average burstrate over 600kbps.

VI. C ONCLUSION

In this paper, we presented the analysis and simulationresults for the link budgets of a cdma2000 1xEV-DOsystem. It is shown that 1xEV-DO has link budgetadvantages over IS-95-A of approximately 10 dB on theforward link and 1.5 dB on the reverse link.

The 1xEV-DO forward link provides the link budget gainover IS-95-A from the following sources: 1) Coding gain of 2.0 dB: 1xEV-DO uses turbo-code as opposed toconvolutional code in IS-95-A; 2) Variable rate gain of 7.0dB: 1xEV-DO uses rate control and ARQ as opposed topower control in IS-95-A forward link; 3) Multi-userdiversity gain of 2.0 dB: 1xEV-DO uses proportional fairscheduling algorithm that exploits multi-user diversity. Atthe same time, 1xEV-DO loses 1.5 dB of soft handoff gain

because 1xEV-DO uses selection diversity soft handoff asopposed to the power combined diversity soft handoff of IS-95-A. These factors contribute to approximately 10 dBforward link budget gain for 1xEV-DO over IS-95-A.

Fwd/Rev Link Burst Rate vs. Path Loss

1

10

100

1000

125 130 135 140 145 150 155

Path Loss (dB)

B u r s t R a t e ( k b p s )

Fwd. Link, Single AntennaFwd. Link, Dual AntennaRev. Link, Dual Antenna, System Load=3dBRev. Link, Dual Antenna, System Load=5dB

Fig. 5.1 Fwd/Rev Link Burst Rate vs. Path Loss for1xEV-DO



Table 5.1. 1xEV-DO Forward Link Budget for Single Antenna TerminalTra ff ic Traf fic Con tr ol Cont ro l Eq uat io n

Average Throughput (or datarate) (bps)

9, 600 32,175 38, 400 76, 800

Average Burst Rate (bps) 67,100 225,000 N/A N/AServing Time Fraction (%) 14.3 14.3 N/A N/ABandwidth (Hz) 1228.8k 1228. 8k 1228. 8k 1228.8k Bandwidth (dB-Hz) 60.9 60.9 60.9 60.9 ABTS Tx Power (Watts) 15.0 15.0 15.0 15.0BTS Tx Power (dBm) 41.8 41.8 41.8 41.8 BBTS Antenna Gain (dBi) 17.0 17.0 17.0 17.0 C

BTS Cable Loss (dB) 3.0 3.0 3.0 3.0 DBTS EIRP (dBm) 55.8 55.8 55.8 55.8 E=B+C-DMS Rx Antenna Gain (dBi) 0.0 0.0 0.0 0.0 FBody Loss (dB) 3.0 1 3.0 3.0 3.0 G

Noise Figure (dB) 9.0 9.0 9.0 9.0 HThermal Noise (dBm/Hz) -165.0 -165 .0 -1 65. 0 -165. 0 I = -1 74. 0 +

HTarget PER (%) 2 2 2 6(Ior/No)req Per Antenna (dB) -7.0 2.5 4.0 4.0 JMulti-user Diversity Gain (dB) 2.0 1.0 N/A N/ARx Diversity Gain (dB) N/A N/A N/A N/AMS Receiver Sens it iv ity (dBm) -111.1 -101.6 -100.1 -100.1 K=I+J+ALog-normal Std. Deviation (dB) 8 8 8 8Log-normal Fade Margin (dB) 10.3 10.3 10.3 10.3 L

Soft Handoff Gain (dB) 2 4.1 4.1 4.1 4.1 M

Building Penetration Loss (dB) 10.0 10.0 10.0 10.0 NMaximum Pass Loss (dB) 147.7 138. 2 136.7 136.7 O=E-K+F-

G-L+M-N

Table 5.2. 1xEV-DO Forward Link Budget for Dual Antenna TerminalTra ff ic Traf fic Con tr ol Cont ro l Eq uat io n

Average Throughput (or datarate) (bps)

9, 600 70,785 38, 400 76, 800

Average Burst Rate (bps) 67,100 495,000 N/A N/AServing Time Fraction (%) 14.3 14.3 N/A N/ABandwidth (Hz) 1228.8k 1228. 8k 1228. 8k 1228.8k Bandwidth (dB-Hz) 60.9 60.9 60.9 60.9 ABTS Tx Power (Watts) 15.0 15.0 15.0 15.0BTS Tx Power (dBm) 41.8 41.8 41.8 41.8 BBTS Antenna Gain (dBi) 17.0 17.0 17.0 17.0 CBTS Cable Loss (dB) 3.0 3.0 3.0 3.0 DBTS EIRP (dBm) 55.8 55.8 55.8 55.8 E=B+C-DMS Rx Antenna Gain (dBi) 0.0 0.0 0.0 0.0 FBody Loss (dB) 3.0 3.0 3.0 3.0 GNoise Figure (dB) 9.0 9.0 9.0 9.0 HThermal Noise (dBm/Hz) -165.0 -165 .0 -1 65. 0 -165. 0 I = -1 74. 0 +

HTarget PER (%) 2 2 2 2(Ior/No)req Per Antenna (dB) -11.6 2.5 -8.0 -4.5 JMulti-user Diversity Gain (dB) 2.0 N/A 3 N/A N/A

Rx Divers it y Gain (d B) 4. 6 ∞4 12.0 ∞

MS Receiver Sens it iv ity (dBm) -115.7 -101.6 -112.1 -108.6 K=I+J+ALog-normal Std. Deviation (dB) 8 8 8 8Log-normal Fade Margin (dB) 10.3 10.3 10.3 10.3 LSoft Handoff Gain (dB) 4.1 4.1 4.1 4.1 MBuilding Penetration Loss (dB) 10.0 10.0 10.0 10.0 NMaximum Pass Loss (dB) 152.3 138. 2 148.7 145.2 O=E-K+F-

G-L+M-N

ACKNOWLEDGMENT

The authors thank Mehmet Gurelli and Eduardo Estevesfor their assistance providing the simulation and RobertoPadovani for his comments that led to improvements in thispaper.

1 For non hand-held terminals, e.g., wireless data modems, the body loss can beassumed to be zero.2 The 1xEV-DO forward link uses selection diversity when in handoff. Morespecifically, the mobile selects a base station that has the best signal level as itsserving base station. For selection diversity soft handoff, it is shown that the requiredfade margin is 6.2dB, which leads to a soft handoff gain is 4.1dB compared with therequired fade margin of 10.3dB for hard handoff [5].3 Due to the assumed geometry, the average throughput of 70.8kbps cannot beachieved for single antenna terminals, thus multi-user diversity gain we defined cannotbe derived for this case.4 Due to the same reason above, the Rx diversity gain is ∞.

Table 5.3 IS-95-A Forward Link BudgetTraffic Paging Equation

Data Rate (bps) 9,600 9,600Data Rate (dB-Hz) 39.8 39.8 ABTS Tx Power (Watts) 15.0 15.0BTS Tx Power (dBm) 41.8 41.8Max. % Power for Each Channel 5.3 20Max. Power Allocated per CH (Watt s) 0 .8 3 .0Max. Power Allocated per CH (dBm) 29.0 34.8 BBTS Antenna Gain (dBi) 17.0 17.0 CBTS Cable Loss (dB) 3.0 3.0 D

BTS EIRP per TCH (dBm) 43.0 48.8 E=B+C-DMS Rx Antenna Gain (dBi) 0.0 0.0 FBody Loss (dB) 3.0 3.0 GNoise Figure (dB) 9.0 9.0 HThermal Noise (dBm/Hz) -165.0 -165.0 I=-174.0+GTarget PER (%) 3 10( Eb/No)req for Single Antenna (dB) 12.3 5 20.6 J

MS Receiver S ens itivit y (dBm) -112.9 -104. 6 K=I+J+ ALog-normal Std. Deviation (dB) 8 8Log-normal Fade Margin (dB) 10.3 10.3 LSoft Handoff Gain (dB) 5.6 4.1 MBuilding Penetration Loss (dB) 10.0 10.0 NMaximum Pass Lo ss (dB) 138.2 134. 2 O= E- K+F-G-L+M -N

Table 5.4 1xEV-DO and IS-95-A Reverse Link BudgetsEV-DO EV-DO IS-95 Equation

Data Rate (bps) 9,600 19,200 9,600Data Rate (dB-Hz) 39.8 42.8 39.8 AMS Tx Power (mWatts) 200 200 200MS Tx Power (dBm) 23.0 23.0 23.0 B

MS Antenna Gain (dBi) 0.0 6 0.0 0.0 C

Body Loss (dB) 3.0 3.0 3.0 DMS EIRP for Data Channel(dBm)

20.0 20.0 20.0 E=B+C-D

BTS Rx Antenna Gain (dBi) 17.0 17.0 17.0 FBTS Cable Loss (dB) 3.0 3.0 3.0 GBTS Noise Figure (dB) 5.0 5.0 5.0 HBTS T he rm al Nois e ( dBm /Hz) - 16 9. 0 - 16 9. 0 - 16 9. 0 I= -17 4. 0+HTarget PER (%) 2 2 3Total ( Eb/No)req per Antenna @no system load (dB)

6.6 5.0 8.0 J

System Load Margin (dB) 3.0 3.0 3.0 KBTS Receiver Sensit iv ity (dBm) -119.6 -118.2 -118.2 L=I+J+K+ALog-normal Std. Deviation 8 8 8Log-normal Fade Margin (dB) 10.3 10.3 10.3 MSoft Handoff Gain (dB) 4.1 4.1 4.1 NDifferential Fade Margin (dB) 2.1 2.1 2.1 OBuilding Penetration Loss (dB) 10.0 10.0 10.0 PMaximum Path Loss (dB) 135.3 133.9 133.9 Q=E-L+F-G-

M+N-O-P

REFERENCES

[1] 3 rd Generation Partnership Project 2 (3GPP2) "cdma2000High Rate Packet Data Air Interface Specification", C.S20024v2.0 October 2000.

[2] P. J. Black, et. al. “Capacity simulation of cdma2000 1xEVwireless internet access system,” IEEE MWCN 2001, pp. 90-96, August 2001.

[3] TIA/EIA-98-C Recommended Minimum PerformanceStandards for Dual-Mode Spread Spectrum Mobile Stations.

[4] Rec.ITU-R M.1225 Guidelines for Evaluation of RadioTransmission Technologies for IMT-2000.

[5] A. J. Viterbi, et. al. “Soft handoff extends CDMA cellcoverage and increase reverse link capacity,” IEEE Journal onSelected Areas in Communications, vol. 12, No. 8, pp. 1281-

1288, October 1994.

5 Assume 2-way soft handoff with two received signals having the same powerspectrum density. No third cell interference, i.e., Ioc=0. So it is better geometry thanwhat we assumed for 1xEV-DO link budget calculation. Also, the required averageEb/No is obtained assuming 3% target FER, a looser constraint than the 2% targetPER assumed in 1xEV-DO.6 Non hand-held terminals may yield higher antenna gain. The comparison hereassumes mobile handset.

Link Budget of Cdma2000 1xev-Do Wireless Internet Access System

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