Date:11 May, 2009 Abstract: This contribution contains framework and components proposal update for DOrC Notice Contributors grant a free, irrevocable license to 3GPP2 and its Organizational Partners to incorporate text or other copyrightable material contained in the contribution and any modifications thereof in the creation of 3GPP2 publications; to copyright and sell in Organizational Partner’s name any Organizational Partner’s standards publication even though it may include all or portions of this contribution; and at the Organizational Partner’s sole discretion to permit others to reproduce in whole or in part such contribution or the resulting Organizational Partner’s standards publication. Contributors are also willing to grant licenses under such contributor copyrights to third parties on reasonable, non-discriminatory terms and conditions for purpose of practicing an Organizational Partner’s standard which incorporates this contribution. This document has been prepared by contributors to assist the development of specifications by 3GPP2. It is proposed to the Committee as a basis for discussion and is not to be construed as a binding proposal on Contributors. Contributors specifically reserves the right to amend or modify the material contained herein and nothing herein shall be construed as conferring or offering licenses or rights with respect to any intellectual property of Contributors other than provided in the copyright statement above. DO Rev. C Framework Proposal Update Recommendation : review and adopt Source:Shu Wang and Tony Lee VIA Telecom Contact:{shuwang, C

DO Rev. C Framework Proposal Update Shu Wang and Tony Lee {shuwang, VIA Telecom

Introduction In the previous framework contribution, C , VIA presented some views on DO Rev. C  break the coverage/throughput dilemma  improve the support for delay sensitive services  improve the support for location services and local multicast In this contribution, VIA would like to outline DO Rev. C framework from the following considerations  Strictly backward compatibility  Rank deficiency issue of multi-antenna transmission  The impact of MIMO on DO VoIP  The tradeoff between VoIP capacity and sector throughput VIA proposes subband OFDMA/MIMO as well as many other enhancements for DO Rev. C.

DO Evolution: Keep the Momentum DO Rev. A: provides FL peak data rate of 3.1 Mbps and RL 1.8 Mbps in a 1.25 MHz FDD carrier. DO Rev. B: with the 64-QAM scheme, the FL peak data rate increase to 4.9 Mbps per MHz. An aggregated 5 MHz will deliver up to 14.7 Mbps and up to 73.5 Mbps within 20 MHz. DO Rev. A/B have a very good support of delay sensitive service: multi-user packets, QoS scheduler, H-ARQ, etc. DO Rev. C promises higher link and sector throughput, improved delay sensitive service support, improved BCMCS, etc.

Strictly Backward Compatibility Adding OFDM into DO Rev. A/B is not something completely new to us. In DO Rev. A/B, the data portion in each interlace can be  Unicast data as in traditional EV-DO, IS-856  Broadcast/Multicast data, CDM or OFDM For the sake of strictly backward compatibility, it is recommended to replace a certain number of DO interlaces with DO Rev. C, which can be OFDMA or OFDM interlaces.

Break The Coverage/Throughput Dilemma

Multi-Antenna Transmission for DO Multi-antenna techniques are believed to be critical in meeting the demand of high data rate and high link quality.  Improve link quality: spatial diversity and beamforming  Improve link throughput: spatial multiplexing Multi-antenna techniques can be employed for both forward link and reverse link transmission. However, there are issues which should be carefully considered in implementing multi-antenna techniques in DO Rev. C.  The rank deficiency issue.  The impact of multi-antenna techniques on other services.

Multi-ANTenna AT It is non-trivial to “ squeeze ” more and more antennas and RFs into a mobile phone with considering  Power consumption.  Mechanical limitation.  Multiple radio interfaces there already: GPS, bluetooth, WiFi, …  Antenna spacing requirement.  For more spatial diversity gain, the separation should be larger than 0.5λ  For 2GHz, the wavelength is about 15cm or 5.9 inch.  Operating frequency bands. In addition, the achievable MIMO channel capacity also depends on the scattering statistics as well as the antenna configuration.  The scattering statistics is usually quantified with angular intervals.  The antenna array configuration can be characterized by the area/size limitation and the shape.

Achievable Spatial Degree of Freedom 6 spatial cluser, angle spread = 35 o, dual-polarized antenna array, f = 2GHz

Rank Deficiency and Multiuser MIMO Without considering AT size, the achievable spatial multiplexing gain is limited by spatial scattering.  In the case of a typical 4x4 MIMO, less than 1% of the users are able to use rank 4.  Around 90% users have either rank 1 or 2. For an AT with the physical size of a few times of wavelength, e.g., about 0.5~3, the achievable spatial multiplexing gain is limited by the angle spread, AT size and C/I ratio.  This is the case for practical multi-antenna mobile devices.  The expected spatial multiplexing gain mostly is less than 3. For achieving the full potential of multi-antenna transmission, it is necessary to explore the spatial multiplexing gain not only in link level but also in system level. Therefore, it is recommended to include the following for DO Rev. C  MIMO/OFDMA  Multiuser MIMO

VoIP User Capacity in DO Rev. A Theoretically, DOrA VoIP capacity is upper bounded at 96 users/carrier with an assumption of 8-AT MUP for every VoIP frame. In reality, DOrA VoIP capacity is upper bounded at 66 ATs/sector due to the limitation of available MAC indices or RL RoT The introduction of new MIMO/OFDM subtype(s) in DO Rev. C brings us new opportunities and challenges in optimizing DO VoIP services. Source: Qualcomm Incorporated.

VoIP Capacity / Sector Throughput Dilemma Source: Qualcomm Incorporated.

The Impact of MIMO on DO VoIP The introduce of CL-MTD may help increase DO VoIP user capacity.  It alleviates the existing RL limitation on VoIP capacity. The introduce of FL-MIMO interlace/subtype might, however, limit DO VoIP user capacity if it is not treated carefully.  A FL MIMO 8-subpack interlace might reduce the scheduling opportunity for up to 32 VoIP ATs. Source: Alcatel-Lucent and Qualcomm

VoIP User Capacity and Multiuser Packets Through DO single-user packet has the advantage of high throughput, minimum control overhead and simple receiver design requirement, it is not friendly in supporting delay sensitive services. Higher VoIP user capacity can be achievable through packing more than one users in single transmission. It is recommended to include multiuser packet design in DO Rev. C.  Besides the existing CDM MUP, OFDMA MUP should be included.  For higher throughput with VoIP, it is recommended to provide the capability to mix MIMO traffic with VoIP traffic in DO Rev. C.

DO Rev. C Air Interface: A VIA’s View The adoption of multi-antenna techniques promises to improve the performance of existing DO network infrastructure.  Improved link quality: spatial diversity and beamforming  Higher Date rate: spatial multiplexing, multiuser MIMO MIMO OFDMA with antenna selection provides a balance between DO Rev. A/B and the full MIMO DO.  OFDMA can also bring additional dimensions in optimizing DO network when combined with multi-antenna techniques.  It can improve the delay-limited capacity for VoIP-liked services Subband interference avoidance through OFDMA can help improve cell-edge user experience. Simple Forward Link Multicast with Supercasting.

MIMO-OFDMA Multiuser Packet for DO Rev. C

MIMO Reliability/Throughput Tradeoff

Interference Avoidance with Subband FFR Interference management can be done in the subband level.  Interference avoidance is achievable in time domain (slots), frequency domain (subbands), space domain (sectors) and even through power allocations.  Finer granularity means higher achievable efficiency.  It help mobile do handoffs with less ping-pong. Subband frequency reuse can be done either through network planning or the full CQI report from the cell-edge ATs.

OFDMA and Supercasting

Simple FL Multicast with Supercasting Many emerging mobile services, e.g., alert service and positioning assistance service, require the same FL multicast to cover multiple sectors.  It is similar to the full-fledged BCMCS but only for low data rate service, such as text message broadcast.  Its coverage is expected to be more flexible. For example, a couple of sectors or even one sector only. Simple FL multicast with superimpose multicast traffic and unicast traffic help achieve higher spectral efficiency in DO network and minimize the impact of multicast traffic on the existing DO traffic.

Conclusions For DO Rev. C, it is important to consider the following issues when we introduce OFDM/MIMO into the existing CDM DO.  Strictly backward compatibility  Rank deficiency issue of multi-antenna transmission  The impact of MIMO on DO VoIP  The tradeoff between VoIP capacity and sector throughput VIA proposes the followings for DO Rev. C  MIMO-OFDM single-user packet  MIMO-OFDMA multiuser packet  Subband Interference avoidance capability  Low Data Rate FL multicast with supercasting

VIA Forward Link Configuration (1/4) Frame Structure. The CDM pilots and MAC channels of DO Rev. A/B are kept for SBC. Numerologies: follow the same design as Qualcomm proposed.  OFDM symbol length 200 chips.  OFDM preamble length 20 chips. OFDMA subband unit: 45 tons each subband, which is one quarter of MHz.  Subband Configuration can be 1)[1], 2)[¼ ¼ ¼ ¼], 3)[½, ½], 4)[¼ ½ ¼], 5)[½ ¼ ¼], 6)[¼ ¼ ½]  Subband Configuration 1) is OFDM Antenna Configurations:  Forward Link  Baseline: 2x2 or 4x2  Optional: 4x4  Reverse Link  Baseline: 1x2 or 1x4  Optional: 2x2 or 2x4

VIA Forward Link Configuration (2/4): SUP The same as Qualcomm’s OFDM/MIMO proposal. C  Preamble:  8-bit MAC ID  2-bit packet format indication relative to requested DRC Enables AN to serve user a smaller than max size packet format  Data:

VIA Forward Link Configuration (3/4): MUP Preamble: Additional OFDMA Preamble Subchannel, which is tail-biting convolutional coded  Coding rate: 1/3  Constraint length: 9  Generator polynomials: (0557, 0663, 0711) OFDMA Preamble Subchannel includes the fields  Subband Configuration (2 bits)  SubpacketInfo(10 bits): 8-bit MAC ID + 2 bit Rate Indicator. As indicated by the SubpacketInfo field in OFDMA Preamble Subchannel, It is allowed to transmit the following packet types in each subband,  regular OFDM single-user packet,  MIMO/OFDM single-user packet, either SCW, MCW, or precoded.  DO Rev. A MUP

OFDMA-MIMO Each AT reports DRC for desired subband(s). For example,  For each single-antenna AT, it reports DRC/PMI for each of the four subbands.  For each dual-antenna AT, it reports two DRC/PMI for each of two subbands. Four bits indicate the data rate request and 3 bits indicate the desired serving sector. The channel has 64-ary bi-orthogonal modulation. The DRC is sent on the Walsh codes W 8 32 and W and multiplexed on the I and Q branches, which is similar to the DRC report in the MCW mode.

Multiuser MIMO Each AT reports DRCs/PMIs for the desired subband(s).  For each single-antenna AT, it reports DRC/PMI for each of the four subbands.  For each dual-antenna AT, it reports two DRC/PMI for each of two subbands. The AN does the MIMO spatial multiplexing based on the PMI feedbacks from multiple ATs.  Optional: transmitted DRCs/PMIs may be broadcasted through FL preamble.