1 Elimination of Repeated Information in Persistent Allocation Sub-burst IEs Yair Bourlas, Nextwave Kamran Etemad, Intel Shantidev Mohanty, Intel Mo-Han Fong, Nortel Geunhwi Lim, Samsung Electronics Jianmin Lu, Huawei Technologies Sean McBeath, Huawei Technologies Changyoon Oh, Samsung Electronics Hua Xu, Motorola

2 MAP Overhead for VoIP  VoIP allocations are typically of small size, e.g. AMR 12.2Kbps –44 bytes in active state and 18 bytes in inactive state  Large number of VoIP allocations per frame, e.g., per frame –This leads to large number of Sub-Bursts IEs to specify the allocation information (when HARQ is used)  Large number of Sub-Burst IEs incur high MAP overhead adversely affects VoIP capacity  Observation: Many VoIP allocations have similar MCS and/or size. –This is because VoIP packet size is same when same CODEC is used by all the users and close to one another when different CODECs are used by different users. –These same/similar length VoIP packet sizes result in similar allocation size in terms of number of slots (for more refer backup slide # 11)  The size of Sub-Burst IEs can be reduced by exploiting –Multiple allocations with the same MCS (used in Rev2/D2 for DL Chase HARQ and DL IR HARQ for CC) (proposed for other HARQ modes in this contribution) –Multiple allocations with the same allocation size (Proposed in this contribution)

3 Persistent Allocation Sub-Burst IE Optimization in Rev2/D3  IEEE Rev2/D3 uses ‘Sub-Burst DIUC Indicator’ flag in Persistent sub-burst IEs –to eliminate repetitive indication of MCS in the Sub-Burst IEs of N consecutive subbursts having same MCS (DIUC and Repetition Coding Indication) –Only the Sub-Burst IE of the first one of these N subbursts specifies the MCS of allocation –The remaining (N-1) Sub-Burst IEs do not specify the MCS of allocation –A one-bit flag, Sub-Burst DIUC Indicator, is used in the Sub-Burst IE to indicate if the MCS of a subburst is same as that of the previous subburst –This is referred to as MCS Optimization in this contribution  IEEE Rev2/D3 Persistent Sub-burst IEs do not use similar optimization for other information fields such as Duration, Allocation Period, N_ACID

4 Proposed Persistent Sub-Burst IE Optimization  When N consecutive subbursts have same Duration/Allocation Period/N_ACID –Only the Sub-Burst IE of the first subburst specifies the parameter –The remaining (N-1) Sub-Burst IEs do not specify the parameter –A one bit flag, ‘Duration Indicator’, and ‘Allocation Period and N_ACID Indicator’ is used in the Sub-Burst IE to indicate if the corresponding parameter of a subburst has same information as of the previous sub-burst.

5 An Example Persistent Allocation in a Randomly Chosen frame  Persistent Chase Sub-burst IE –IE Index MCS Duration Allocation Period N_ACID – – – – – – – – – – – – – – – Observation: many VoIP allocations have same Duration and/or Allocation Period, N_ACID

6 What is done now for the Example Persistent Allocation in a Randomly Chosen frame  Persistent Chase Sub-burst IE –IE Flag 1 MCS Duration Allocation N_ACID Index Period – – – – – – – – – – – – – – – Observation: many VoIP allocations have same Duration and/or Allocation Period, N_ACID

7 Proposed Optimization for Persistent Sub-Burst IE in Rev2/D3 of the Example DL Allocation  Persistent Chase Sub-burst IE –IE Flag 1 MCS Flag 2 Duration Flag 3 Allocation N_ACID Index Period – – – – – – – – – – – – – – – Observation: many VoIP allocations have same Duration and/or Allocation Period, N_ACID

8 Number of DL Slots for a VoIP Packet MCS# Slots: active (44 bytes) # Slots: silence (18 bytes) 1: QPSK ½ STBC (rep. 6)4418 2: QPSK ½ STBC (rep. 4)3012 3: QPSK ½ STBC (rep. 2)156 4: QPSK ½ STBC (rep. 1)83 5: QPSK 3/4 STBC (rep. 1) 52 6: 16 QAM 1/2 STBC (rep. 1) 42 7: 16 QAM 3/4 STBC (rep. 1) 31 8: 64 QAM 1/2 STBC (rep. 1) 31 9: 64 QAM 2/3 STBC (rep. 1) 21 MCS# Slots: active (44 bytes) # Slots: silence (18 bytes) 10: 64 QAM 3/4 STBC (rep. 1)21 11: 64 QAM 5/6 STBC (rep. 1)21 12: QPSK ½ SM (rep. 1)42 13: QPSK 3/4 (rep. 1)31 14: 16 QAM 1/2 SM (rep. 1)21 15: 16 QAM 3/4 SM (rep. 1)21 16: 64 QAM 1/2 SM (rep. 1)21 17: 64 QAM 2/3 SM (rep. 1)11 18: 64 QAM 3/4 SM (rep. 1)11 19: 64 QAM 5/6 SM (rep. 1)11 Multiple MCS options have similar allocation size

9 Summary  The proposed technique is very simple to implement  Up to 40 % MAP reduction  Robust against –Variable voice codec –Variable VoIP packet because of header compression, active/silence –Applicable when different users use different codec –Backbone delay variation –Useful across all mobility (slow, medium, fast users)