Exhibit 1016
`
`ZTE Corporation and ZTE (USA) Inc.
`
`

`
`Inv. No. 337-TA-868
`RX-3076
`
`R1-02-1238
`
`3GPP TSG-WG1#28bis
`
`Espoo, Finland
`October 8-9, 2002
`
`Agenda item:
`
`HSDPA
`
`Source:
`
`Title:
`
`Lucent Technologies
`
`Code limitation and code reuse in HSDPA
`
`Document for: Discussion
`
`1
`
`Introduction
`
`The orthogonal code space is an imporLant sysLem resource for WCDMA DL transmission. Orthogonal transmission is
`achieved by allocating OVSF codes to different control and data ct~annels. For HS-DSCH, multiple SF-16 codes can
`be used for DL transmission within a snbfi~ame. The HS-DSCH provides a highly efficient radio link and can
`potentially support a large number of users. However, the capacity of HS-DSCH can be limited considerably due to a
`shortage of available orthogonal codes.
`
`1.1
`
`Causes of Code Limitation in HSDPA
`
`The shortage of codes can result due to various reasons including inefficient code space usage by associated DPCH for
`HSDPA users (basically ca~ying pilot and power control inforlnation) and other dedicated cham~els [1]. For R’99 data
`services, an inactivity- tin~er is typically employed to enst~re that code resources are released tbr other nsers. However,
`there arc certain data applications (e.g. chatty applications, TCP acknowledgements) for which long inactivity timers
`may be needed in order to ensure low- delay. As a result, these applications tend to use up significant fractions of the
`code space but have very low power requirements. Voice users could also make inefficient use of code space since
`codes remain assigned during periods of inactivity. This leads to power code imbalance, an effect further compounded
`by soft handoff on the do~l~link. Enhancements that provide power benefit (e.g. beamforming) also need
`corresponding improvements in the code dimension so that the system capacity benefits can be realized, l’hese effects
`can result in a disproportionately large amount of power available for HS-DSCH as compared to codes.
`
`1.2 Effect of Code Limitation on HSDPA
`
`In this section, we show how code limitation can substantially constrain the throughputs achieved in HSDPA.
`Precisely, we present the OTA and service throughput attained using single antenna (i.e., no transmit diversity) and
`CLTD Mode-1. In particular, we consider two cases: one where only 25% of the code space is available for HSDPA
`(i.e., the system is code space constrained) and another where 62.5% of the code space is available (i.e., the system is
`not code space constrained). In both cases, 63% of the overall power fraction is assumed to be available for HSDPA.
`Figmre 1 and Figure 2 below plot the ()TA and service throughput attained in each of the above cases in a single path
`Raylcigh fading channel model. Observe that in the code-constrained case, the service throughput and OTA remain
`virtually unchanged as the load in the system - measured in terms of the number of UEs - increase. This clearly
`illustrates the effect on system capacity due to the code-power imbalance in the code-constrained case.
`
`With the availability of 2 transmit antennas, transmit diversity schemes such as closed loop (TxAA) can be used for
`IIS-DSCII [2]. These transmit diversity techniqnes provide link level performance improvements leading to overall
`system capacity- improvement. However, the gains achieved by the transmit diversity schemes can be small when the
`system is code limited. This is due to the fact that transmit diversib~ provides power benefit by achieving a given
`performance with smaller power (EJIo~) required compared to a single antenna transmission bat does not help solve
`the code limitation problem.
`
`The code lhnitation problem can be partly resolved by using higher coding rates and high order modulations.
`However, high coding rates and higher order modulations come with associated penalties thus impacting the overall
`
`N K8681TCO 13089571
`ZTE Corporation and ZTE (USA) Inc.
`Exhibit 1016-00001
`
`

`
`system capacity. Furthermore, in some cases, higher order modulations may not be available - the highest order
`modulation available for HS-DSCH is 16QAM. Moreover, the introduction of HSDPA UE classes that only support
`QPSK ensures that higher rates can be achieved only by using a larger number of codes. MIMO techniques can also
`solve the code limitation problem but require multiple transmit and multiple receive antermas.
`
`In what follows, we address the code limitation problem through OVSF code reuse approaches that allow higher
`system capacity to be achieved without requiring multiple receive antennas.
`
`3500
`
`3000
`
`2500
`
`2000
`
`1500
`
`1000
`
`500
`
`0
`
`3500
`
`3000
`
`2500
`
`2000
`
`1500
`
`1000
`
`500
`
`0
`
`] SA (25% code space)
`
`[] CLTD (25% code space)
`
`[] SA (62.5% code space)
`
`[] CLTD (62.5% code space)
`
`37 UEs
`
`56 UEs
`
`75 UEs
`
`100 UEs
`
`Figure 1. OTA with single antenna and CLTD Mode-1.
`
`[] CLTD (25% code space)
`
`I [] S A (25% code space)
`
`[] SA (62.5% code space)
`[] CLTD (62.5% code space)
`
`37 UEs
`
`56 UEs
`
`75 UEs
`
`100 UEs
`
`Figure 2. Service throughput with single antenna and CLTD Mode-1.
`
`NK8681TC013089572
`ZTE Corporation and ZTE (USA) Inc.
`Exhibit 1016-00002
`
`

`
`2 Code Reuse
`
`The reuse of OVSF codes results in additional in-sector interference that needs to be managed through suitable
`techniques (interference averaging, interference cancellation and/or interference rejection) in order to achieve the
`desired benefits without a significant power penalty.
`
`R’99 specifications allow the OVSF code space to be expanded through the use of one or more Secondary Scrambling
`Codes (SSCs) [3] (also see related references on code space expansion through QoFs and related topics [4][5]). Here,
`we explore both the use of SSCs and/or multi-antenna scheduling techniques to achieve code reuse in HSDPA with
`effective management of resultant interference.
`
`2.1
`
`Code Reuse Options
`
`Two alternatives for code reuse in HSDPA are now described:
`
`Option-l: Partial Code Reuse - Here, only the codes set aside for HSDPA are candidates for reuse (see Figure
`1). Reusing the codes set aside for dedicated channel users is not an option as they do not get any processing
`gain benefit in rejecting the cross interference. This approach does not expand the code space to the maximal
`extent but has the advantage of maintaining orthogonal transmissions to the dedicated channel users, thereby
`leaving the interference to them unchanged. The basic transmission approach suggested here is to
`simultaneously schedule data intended for different IdEs by utilizing two transmit antennas and reusing the
`available OVSF space for HSDPA UEs. The fundamental principle exploited in the simultaneous scheduling
`of multiple users with code reuse is to ensure that users selected on each antenna have good %ross-antenna
`rejection" [6], i.e., a user scheduled on antenna 1 has a strong charmel from that antenna and a comparatively
`weak channel from antenna 2. Users on antenna 2 are selected in the same manner. This will keep the cross
`interference experienced by each user low. With sufficient load, pairs of users that satisf~v this condition can
`be found in the cell with high probability. The power distribution across the two antennas can be performed
`in a number of ways. A useful method is to split the total cell power equally across the two antennas (in a
`manner similar to STTD and CLTD Mode-l).
`
`Ant 1
`
`Ant2
`
`Codes used by control and
`dedicated channels.
`
`Codes not used (No
`transmission).
`
`Codes available for HS-
`PDSCH.
`
`HS-PDSCH codes reused.
`
`V
`
`Primaa’y scrambling code
`
`Figure 1. Partial code reuse scheme
`
`Option-2: Full Code Reuse - If a secondary scrambling code is activated, then the entire OVSF code space on
`the SSC is available. So HSDPA users can be scheduled on a part of the Primary Scrambling Code (PSC)
`space originally assigned and the entire SSC code space. The introduction of a SSC allows full reuse of the
`OVSF code space and can be achieved in the following ways:
`
`NK8681TC013089573
`ZTE Corporation and ZTE (USA) Inc.
`Exhibit 1016-00003
`
`

`
`Introduction of SSC on Same Antenna(s) as PSC: The use of a SSC on the same antenna(s) as a
`Primary Scrambling Code (PSC) may lead to excessive interference to UEs on both the PSC and
`the SSC since the instantaneous channel gains on the desired signal and interference
`con~ponents are perfectly correlated. Multi-user detection techniques can be applied to cancel out
`the resulting interference, albeit at the cost of additional UE complexity [5].
`
`2.
`
`Introduction of Antenna Specific SSC: This allows cross antenna interference rejection through
`scheduling, in a manner similar to that in Option 1 above, in addition to the interference
`rejection benefits of the SSC itself..
`
`Although dedicated channel users on the PSC get the processing gain benefit in rejecting SSC interference,
`unlike in Option 1, some additional interference due to the SSC cannot be avoided. This increase in
`interference will therefore have to be offset by increasing the power allocation to dedicated charmel users.
`Although this does result in a reduction in the overall power fraction left for the data users, the increase in the
`code space available due to the introduction of the SSC still results in system capacity improvement in code-
`limited situations.
`
`Depending on the severity of code limitation encountered, full or partial code reuse may be employed in order to
`expand the OVSF code space. These techniques can be combined with other interference avoidance techniques (e.g.
`beamforming) in order to further improve pertbrmance. The signalling support needed tbr full or partial code reuse is
`for further study. Additional signalling - both in the uplink and downlink - will improve the performance of code
`reuse and improve the robustness of the schemes.
`
`3 Conclusions
`
`Code reuse is proposed as a method of increasing the OVSF code space for HS-DSCH. The schemes can alleviate the
`code limitation problem and enhance HSDPA throughput in these situations. The quantitative benefits of these
`schemes and the signalling support necessary to accommodate them are for further study.
`
`References
`
`[1]
`
`[2]
`
`"DL structure in support for HS-PDSCH", R1-01-0478, Qualcomm.
`
`"Transmit diversity for HSDPA", R1-02-0530, Lucent.
`
`[3] 3GPP TS 25.213 V5.2.0, ~°Spreading and Modulation (FDD)," Release 5.
`
`[4] K. Yang, Y-K. Kim, P.V. Kumar, "Quasi-Orthogonal Sequences for Code-Division Multiple-Access
`Systems," IEEE Transactions on InJbrmation Theory, Vol. 46, No. 3, May 2000.
`
`[5] L. Jalloul and A. Shanbhag, "Enhancing Data Throughput Using Quasi-Orthogonal Functions Aggregation
`for 3G CDMA Systems," Proceedings, Spring VTC, 2002.
`
`[6] Achilles Kogiantis and Lawrence Ozarow, "Do~vnlink Best Eftbrt Packet Data with Multiple Antennas,"
`submitted to International Conference on Communications, ICC 2003, Anchorage, Alaska, May 11-15,
`2003.
`
`NK8681TC013089574
`ZTE Corporation and ZTE (USA) Inc.
`Exhibit 1016-00004
`
`

`
`Annex: Simulation parameters
`
`The system level simulation parameters are listed in Table 1 below.
`
`Parameter
`
`Cellular layout
`
`Table 1 Basic system level simulation assumptions.
`
`Explanation/Assumption
`
`Comments
`
`Hexagonal grid, 3-sector sites
`
`Provide your cell layout picture
`
`Site to Site distance
`
`2800 m
`
`Antenna pattern
`
`As proposed in [2]
`
`Only horizontal pattern specified
`
`Propagation model
`
`]~ 128.1 + 37.6 L, oglo(]~)
`
`R in kilometers
`
`CPICH power
`
`Other common channels
`
`-10 dB
`
`- 10 dB
`
`Power allocated to HSDPA Max. 70 % of total cell power
`transmission, including associated
`signaling
`
`Slow fading
`
`As modeled in UMTS 30.03, B 1.4.1.4
`
`Std. deviation of slow fading
`
`Correlation between sectors
`
`Correlation between sites
`
`8 dB
`
`1.0
`
`0.5
`
`Correlation distance of slow fading
`
`50 m
`
`Carrier frequency
`
`2000 MHz
`
`BS antenna gain
`
`UE antenna gain
`
`UE noise figure
`
`14 dB
`
`0 dBi
`
`9 dB
`
`Max. # of retransmissions
`
`Specify the value used
`
`Retransmissions by fast HARQ
`
`Fast HARQ scheme
`
`A21R
`
`BS total Tx power
`
`Up to 44 dBm
`
`Active set size
`
`Frame duration
`
`Scheduling
`
`3
`
`2.0 ms
`
`normalized Max C/I
`
`Specify Fast Fading model
`
`Jakes spectrum
`
`Maximum size
`
`Generated e.g. by Jakes or Filter
`approach
`
`The fundamentals of the data-traffic model are captured in Table 2 below.
`
`Table 2 Data-traffic model
`
`)arameters
`
`Process
`Packet Calls Size
`
`I
`
`Random Variable
`Pareto with cutoff
`
`I
`
`Time Between Packet Calls
`Packet Size
`
`Packets per Packet Call
`Packet Inter-arrival Time
`(open- loop)
`
`Geometric
`Segmented based on MTU
`size
`Deterministic
`Geometric
`
`Parameters
`A=I. 1, k=4.5 Kbytes, m=2 Mbytes, ~ = 25
`Kbytes
`# = 5 seconds
`(e.g. 1500 octets)
`
`Based on Packet Call Size and Packet MTU
`~ = MTU size/peak link speed
`(e.g. [1500 octets * 8]/2 Mb/s = 6 ms)
`
`NK8681TC013089575
`ZTE Corporation and ZTE (USA) Inc.
`Exhibit 1016-00005
`
`

`
`Packet Inter-arrival Time
`(closed-lool~)
`
`Deterministic
`
`TCP/IP Slow Start
`(Fixed Network Delay of 1 O0 ms)
`
`NK8681TC013089576
`ZTE Corporation and ZTE (USA) Inc.
`Exhibit 1016-00006