1. Date:20 July, 2009 Abstract: This contribution contains DO Rev. C Mobile Transmit Diversity Proposal. 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. Reverse Link Mobile Transmit Diversity for DO Rev. C Recommendation : Review and Adopt Source:Shu Wang VIA Telecom Contact:shuwang@via-telecom.comshuwang@via-telecom.com C30-20090720-018R1

2. Reverse Link Mobile Transmit Diversity for DO Rev. C VIA Telecom

3. Outline Mobile Transmit Diversity Spatial Channel Characteristics  Angle Spread  Log-Normal Shadowing  Delay Spread Mobile Transmit Diversity Techniques and Modes Delta Modulation for Beamform Feedback Channel Simulations Summary

4. Mobile Transmit Diversity (1/2) There are at least three kind of diversity sources in CDMA reverse link.  Phase, delay and channel gain. Reverse link mobile transmit diversity (MTD) is the technique proposed to control the relative phase, delay and Tx power of the signal from the secondary mobile transmit antenna.  It can be taken as an opposite of RAKE and equalization receiver techniques employed in the base station. It promises to improved link-budget, increase sector capacity and enhance user experience.

5. Mobile Transmit Diversity (2/2) Transmit Diversity Feedback Channel (TDFC) is transmitted for 1 or 2- slots every 4-slots.  This is configurable. It is transmitted using an additional forward link MAC index.  AT in CL-MTD mode assigned an additional forward link MAC Index Its target performance is same as RPC Channel

6. Spatial Channel Characteristics It is desirable for the phase estimation resolution and feedback to be close to the level of angle spread of AN.  This means the desired beamforming phase estimation resolution is expected to be around 1/8π or even higher. It is also expected to feedback the antenna gain differentiation information at the resolution of the shadowing factor.  6dB or higher resolution is desired. Channel ModelAngle SpreadShadowing FactorDelay Spread Urban Macrocell2o2o 8dB Δ 0 d ε y 1) d is the distance in km 2) ε is an exponent between 0.5-1.0 3) y is a lognormal variant. Suburban Marcocell2o2o 8dB Urban Microcell3 o / 10 o 3dB / 4dB Indoor Small Office5o5o 4dB / 6dB / 8dB Indoor Hotspot5o5o 1.5dB / 1.1dB Rural Macrocell2o2o 6dB / 8dB

7. Beamforming Feedback Modes Three modes of BMFC, including Qualcomm’s proposal, are proposed  Mode 2: Single-Parameter Adjustment. It can be delay, phase or Tx power adjustment.  1 bit per feedback for either delay, phase or Tx after delta modulation  Or 2 bit per feedback for either delay, phase or Tx after direct quantization.  Qualcomm’s proposal on relative phase rotation is included.  Mode 3: Dual Parameter Adjustment. It can be one of the following combinations: (1) Delay and Phase (2) Delay and Tx Power (3) Phase and Tx Power  2 bits per feedback with 1 bit for each parameter after delta modulations on each parameter.  Mode 4: Triple-Parameter Adjustment. TDFC contains phase, delay and Tx power adjustment information.  3 bits per feedback with 1 bit for each parameter after delta modulation on each parameter. In Mode 3 or 4, the feedback bits can be sent either simultaneouly or alternatively. Delta-Sigma Modulation is proposed to encode/decode phase and power information, individually.

8. Proposed Modulation for Feedback

9. Delta Modulations Delta modulation (DM) is a form of differential pulse-code modulation (DPCM).  The difference between successive samples is encoded into n-bit data streams  1-bit or 2-bit feedback is proposed.

10. Simulations (1/2): Phase or Delay Adjustment

11. Simulations (2/2): Tx Power Adjustment

12. Summary Reverse Link Mobile Transmit Diversity is proposed for DO Rev. C For implementing it, the following items are proposed. 1.In addition to phase adjustment, delay adjustment and Tx power adjustment should be included. 2.Three RL-MTD modes are proposed to do single-parameter adjustment, dual-parameter adjustment or triple-parameter adjustment. 3.In addition to 2-bit direct quantization, 1-bit or 2-bit delta modulation is proposed help improve the channel track capability and/or feedback overhead.