812-HD-FDD 和TDD UE的VoLTE增强.docx
HD-FDD和TDDUE的VOLTE增强half-duplexFDDUE的覆盖范围小于全双工UE的覆盖范围,为了最大化half-duplexFDD实现VoLTE覆盖,可以优化上下行资源利用率的机会,例如通过减少下行重复的技术、新的重复因子和调整的调度延迟。假设双向通信,DL和UL语音分组需要在同一时间窗口内传送。对于HD-FDD/TDDUE,这意味着空口时间预算将通过TDM在上下行数据以及控制/反馈传输之间共享。以EVS7.2kbps编解码器和AMR-WB6.6kbps为例,表1计算了传输时间为40ms、有无报头压缩的有效载荷和相应的TBS。本例的最大耦合损耗(MCL:maximumcouplingloss)计算如表2所示,其中目标BLER设置为1%,用于研究具有一个HARQ传输的情况,即仅具有初始传输的情况。表1:TBS计算40ms,RTP级9E合,6个RB的PDSCH是否头压缩?PayloadRTPheaderPDCPRLCMACBRS+PHRPayload+HeadersTBSCodedbitsR是18*23*22*221039240814400.3000否18*260*22*22101304135228800.477840ms,RTP级聚合,6个RB的PDSCH是否头压缩?PayloadRTPheaderPDCPRLCMACBRS+PHRPayload+HeadersTBSCodedbitsR是18*23*22*22164405048640.5370否18*260*22*22161352135234560.3981表2:MCL计算物理信道名称PUSCHPDSCH,1RxAnPDSCH,2Rx-Ans发送(0)最大TX功率(dBm)234646实际TX功率(dBm)2336.7936.79接收(2)热噪声密度(dBmHz)-174-174-174(3)接收机噪声系数(dB)599(5)占用的信道带宽(Hz)54000010800001080000(6)有效噪声功率=(2)+(3)+10log(5)(dBm)-111.68-104.67-104.67(7)要求的SlNR(dB)-6.103.60-3.20(8)接收器灵敏度=(6)+(dBm)-117.78-101.07-107.87(9)MCL基线=(l)-(8)(dB)140.78137.86144.66RL=32RL=4RL=4TBS=456TBS=408TBS=408按照MCL计算的相同步骤,表3和表5分别给出了单播PDSCH和PUSCH传输的各种TBS和RL的MCL。在表4中,还提供了带有2x2天线设置的PDSCH配置的链路级评估结果。表3:具有1x2天线配置的单播PDSCH的MCL(dB).BLER=I%有效负载(bit)6PRB的PDSCH,1x2天线配置RL208256328408504600712808936i134.56134.06132.96132.16131.06129.66128.76128.16127.162137.46136.86135.76135.26133.86133.26132.56132.16131.664140.46139.86138.36137.86137.06136.76135.56135.46134.768142.66142.36141.36140.46139.56139.26138.16138.26137.7616145.76144.76144.26143.36142.96142.36141.86141.16140.86BLER=I%有效负载(bit)6PRBfiPDSCH,1x2天1建配置RL10321192135215441736180019282152279229842130.06129.36128.66127.66127.46127.36124.96124.56123.66122.664133.06132.46131.96130.86130.56130.26129.46129.06127.46127.368135.66135.16134.86134.26133.26133.26132.56132.36131.16130.4616138.66138.56137.56137.36136.16136.66135.76135.16134.26134.0632141.96141.76141.06140.46139.76140.06139.16138.66137.36137.36BLER=I%有效负载(bit)24PRBttPDSCH,1x2天线配置106413841736208829842139.16137.86137.16135.76134.664141.96140.96139.86139.06137.768144.46143.86142.76142.06140.6616147.16146.26145.36144.96143.6632149.96148.96148.46147.46146.76表1:单播PDSCH的MCL(dB),具有1x2和2x2天线配置.BLER=I%有效负载(bit)6PRB的PDSCH,1x2天线Bd>有效负载(bit)6PRB的PDSCH,2x2天线配置RL408135240813521132.16124.36138.96131.662135.26128.66141.86135.964137.86131.96144.66139.068140.46134.86147.26141.8616143.36137.56149.56144.46表5:6PRB的PUSCH的MCL(dB)BLER=I%Payload(bits)forPUSCHwith6PRBsRL2082563284085046007128089362130.97130.77129.77128.67127.67127.17126.37125.97125.274134.07133.47132.27132.17130.87130.27129.67129.37128.578136.97136.17135.27134.87133.97133.27132.67131.97131.2716140.07139.27138.57137.57136.97136.67136.07135.37134.8732143.27142.57142.17141.37140.57139.77139.47138.77138.47BLER=I%Payload(bits)forPUSCHwith6PRBsRL10321192135215441736180019282152279229842124.87122.77122.47121.77120.77120.77120.07119.87116.07114.974127.97126.47125.27125.17124.47124.07123.87123.37121.17120.578130.87129.17128.37128.47127.27127.67126.97126.27124.471243716134.17132.27131.47130.97130.37130.27129.97129.27127.77127.3732138.27135.67135.17134.67133.97133.67133.57132.97131.87131.27比较表3中具有不同分配PRB数量的PDSCHMCL,可以观察到,由于为PDSCH分配了更多的发射功率和增加的编码增益,通过在更大的带宽上传输,PDSCH的覆盖率得到了改善。例如,对于采用24-PRB分配的1384位TBS,PDSCH的覆盖增益约为7.9dB,相比之下,BLER=1%和RL=32时采用6-PRB的1352位TBS,PDSCH的覆盖增益约为7.9dB。此外,从表4可以看出,通过为PDSCH接收配置2个RX天线,可以改善下行覆盖。例如,通过将Rx天线的数目增加到2,对于408比特和1352比特的TBS,在BLER=1%和RL=I6时分别有约6.2dB和6.9dB下行覆盖增益。将TBS映射到不同编解码器的有效负载大小(与表1中的计算类似),表6总结了具有不同编解码器速率的AMR编解码器的MCL注意,EV7.2kbps的结果与AMRTB6.6kbps的结果相同,因为它们具有相同的有效负载大小。下面提供了有无报头压缩的场景。还调查了没有头压缩的情况,因为R。HC可能并不总是可能的,或者ROHC压缩器可能发送未压缩的头,例如在以下情况下:在会话开始时,作为初始上下文建立的一部分,发送完整的报头(即,无协议报头压缩的传输)如果PHY上的VOLTE数据包失败(在HARQ之后;RLC或VOLTE的应用层没有ARQ),接收器可能会发送R。HC反馈,以通知R。HC上下文的错误同步。TX侧的报头压缩器传输完整的报头信息,作为R。HC上下文“刷新和重新初始化”的一部分。在定期刷新ROHC上下文的情况下,例如当ROHC模式为单向时。注意,对于HD-FDDUE,考虑一个HARQ传输,因此目标BLER被设置为1%。此外,不考虑这里的动态调度,因此MCL是基于所需的下行RLS可以在时间预算内计算的。表2:AMR的MCL(dB)编解码器分配给6PRBPDSCH与IRX天线和PUSCH传输。BLER=I%20ms,withheadercompression20ms,withoutheadercompressionType(AMR)Codecrate(kbps)Payload+Headers(DLUL)TBS(DlJUL)DLRLSULRLsMCLPayload+Headers(DLZUL)TBS(DLZUL)DLRLsULRLSMCLNB4.75168/216208/256216137.46624/672712/71248132.67WB6.6208/256208/256216137.46664/712712/71248132.67WB8.85248/296256/328216136.86704/752808/808216132.16WB12.65328/376328/408216135.76784/832808/936216132.16WB14.25360/408408/408216135.26816/864936/936216131.66WB15.85392/440408/504216135.26848/896936/936216131.66WB18.25440/488504/50448133.97896/944936/1032216131.66WB19.85472/520504/600216133.86928/976936/1032216131.66WB23.05536/584600/6004S133.27992/10401032/1192216130.06WB23.85552/600600/60048133.271008/10561192/1192216129.36BLER=I%40ms,withheadercompression40ms,withoutheadercompressionType(AMR)Codecrate(kbps)Payload+Headers(DLUL)TBS(DLUL)DLRLsULRLsMCLPayload+Headers(DLUL)TBS(DLZUL)DLRLsULRLsMCLNB4.75312/360328/408432138.361224/12721352/1352432131.96WB6.6392/440408/504432137.861304/13521352/1352432131.96WB8.85472/520504/600432137.061384/14321544/1544816130.97WB12.65632/680712/712816136.071544/15921544/1736432130.86WB14.25696/744712/808432135.561608/16561736/1736432130.56WB15.85760/808808/808432135.461672/17201736/1736432130.56WB18.25856/904936/936432134.761768/18161800/1928432130.26WB19.85920/968936/1032432134.761832/18801928/1928816129.97WB23.051048/10961192/1192432132.461960/20082152/2152816129.27WB23.851080/11281192/1192432132.461992/20402152/2152816129.27此外,在表7中提供了PDSCH传输的较大带宽覆盖率分析。选择EVS7.2kbps和AMR-WB6.6kbps编解码器作为示例,因为它们在行业中很受欢迎,适用范围很广。可以观察到,当通过24个prb传输PDSCH传输时,HD-FDD的总体覆盖率得到改善。当PDSCH在24个PRB上传输时,EVS7.2kbps/AMR-WB6.6kbps编解码器的覆盖增益约为3.2dB,而不是在6个PRB上传输。表3:EVS7.2kbps或AMRTB6.6kbps编解码器的MCL(dB)比较,比较6-PRB和24-PRB的PDSCH分配.BLER=1%40ms,withoutheadercompressionNumberofPRBsforPDSCHPayload+Headers(DLZUL)TBS(DLUL)DLRLsULRLsMCL61304/13521352/1352432131.96241304/13521384/1352432135.17所以,如果PDSCH性能可以得到改善,HD-FDD/TDD的总体MCL可以得到改善。这主要是由于HD-FDD/TDD的上下行传输之间的TDM特性。当下行MCL得到改进时,下行不再是瓶颈,更少的下行重复就足够了。随着下行重复次数的减少,更多的时间资源可用于PUSCH重复,这有助于提高总体覆盖率。在ReIT3eMTC中,CEModeAUE支持的重复次数在集合4,8,16,32内。因此,为了最大限度地利用HD-FDD/TDDUE的时域资源,并考虑长度为20ms和40ms的VOLTE互传输周期,假设基于SPS的调度,PDSCH和PUSCH的重复因子应满足以下要求:PDSCH_reps+switchingtime+PUSCH_reps=20*n,其中n=L2ooo,对应于VOLTE传输间隔。