1. Month Year
doc.: IEEE yy/xxxxr0
November 2007
Improving Single Stream Device Performance Using Protocol Assisted Switched Diversity
Date:
Authors:
R. R. Miller
AT&T
Florham Park, NJ
R. R. Miller, AT&T
John Doe, Some Company

2. Use of handheld equipment growing Battery life is important
Month Year
doc.: IEEE yy/xxxxr0
November 2007
Motivation
Use of handheld equipment growing
Battery life is important
Multiple receivers are more expensive and consume more power
Multimedia streaming demands better downstream PER to provide good user experience and less radio resource waste due to excessive repeats: Maximizing goodput is the focus
Build on Single Stream Subgroup considerations
Addresses PHY CIDs 1322 (previous draft) and 5444 (current draft)
R. R. Miller, AT&T
John Doe, Some Company

3. PASD Basics Leverage modern signal processing techniques
Month Year
doc.: IEEE yy/xxxxr0
November 2007
PASD Basics
Leverage modern signal processing techniques
Soft-symbol memory
Combining diversity (Maximal Ratio)
Hybrid ARQ
Use two antennas, but switch into single receiver
Synchronize switching with AP via protocol
Provide capability indication to AP that client is PASD-equipped
AP transmits multiple bursts, 1 each per client antenna
STA stores soft symbols from 1st burst (received via antenna 1) & 2nd burst (received via antenna 2)
STA processes 1st burst immediately
Cancel 2nd burst if 1st received OK (ACK immediately)
Else, STA performs MRC on stored 1st & 2nd bursts
STA returns ACK/NAK
R. R. Miller, AT&T
John Doe, Some Company

4. PASD Architecture November 2007 AP Single Stream Client Month Year
doc.: IEEE yy/xxxxr0
November 2007
PASD Architecture AP
Single Stream Client
Antenna 1
Burst 1 M1 R T
A/D
DEMOD
MRC M2 R
Antenna 2
SISO PHY/MAC
Burst 2
Burst 2 T
ARQ
Processor
Simplified Implementation Diagram
R. R. Miller, AT&T
John Doe, Some Company

5. PASD Transmission Diagram
Month Year
doc.: IEEE yy/xxxxr0
November 2007
PASD Transmission Diagram
Received
by Antenna 1
Received
by Antenna 2
Other
Traffic
Other
Traffic
Other
Traffic 1 2 1 1 2 3 4
From AP
From STA
ACK
ACK
NAK
ACK
1st Burst
Unsuccessfully
Decoded
1st + 2nd Burst
Successfully
Decoded
1st Burst
Successfully
Decoded
1st Burst
Unsuccessfully
Decoded
1st + 2nd Burst
Unsuccessfully
Decoded
1st Burst
Unsuccessfully
Decoded
1st + 2nd Burst
Successfully
Decoded
R. R. Miller, AT&T
John Doe, Some Company

6. Only one receiver and antenna switch required
Month Year
doc.: IEEE yy/xxxxr0
November 2007
PASD: Advantages
Only one receiver and antenna switch required
Lower power than conventional combining diversity/MIMO
Lower cost (memory is inexpensive compared to 2nd radio)
Simple implementation using known processing blocks
Extension of client autonomous switched diversity
More reliable than antenna selection during preamble
Effective in changing RF environments (e.g. slow mobility)
Minimizes use of radio resource in good environments
Seamlessly maintains PER/minimizes repeats when environment degrades
Improves seamless VoIP, video, gaming experience.
Performance near MIMO
Can use Space-Time Coding (STC)
R. R. Miller, AT&T
John Doe, Some Company

7. PASD Architecture November 2007 Month Year doc.: IEEE 802.11-yy/xxxxr0
Analysis/Simulation Diagram
R. R. Miller, AT&T
John Doe, Some Company

8. PASD Performance: BER, PER
Month Year
doc.: IEEE yy/xxxxr0
November 2007
PASD Performance: BER, PER
R. R. Miller, AT&T
John Doe, Some Company

9. PASD Performance: Transmissions
Month Year
doc.: IEEE yy/xxxxr0
November 2007
PASD Performance: Transmissions
R. R. Miller, AT&T
John Doe, Some Company

10. PASD Architecture (MIMO)
Month Year
doc.: IEEE yy/xxxxr0
November 2007
PASD Architecture (MIMO) AP
Single Stream Client
Antenna 1
Burst 1 M1 R T
A/D
DEMOD
MRC M2 R
Antenna 2
MIMO PHY/MAC R T
ARQ
Processor T
Burst 2
Simplified Implementation Diagram
R. R. Miller, AT&T
John Doe, Some Company

11. PASD Performance w.r.t. MIMO
Month Year
doc.: IEEE yy/xxxxr0
November 2007
PASD Performance w.r.t. MIMO
R. R. Miller, AT&T
John Doe, Some Company

12. PASD Performance w.r.t. MIMO
Month Year
doc.: IEEE yy/xxxxr0
November 2007
PASD Performance w.r.t. MIMO
R. R. Miller, AT&T
John Doe, Some Company

13. Month Year
doc.: IEEE yy/xxxxr0
November 2007
Recommendation
Incorporate PASD support in the n draft to maximize goodput to low-cost, low power “single stream” handheld devices, especially those that provide real-time application value to mobile users, while preserving the radio resource.
R. R. Miller, AT&T
John Doe, Some Company

14. November 2007
References
“Analysis of a PASD Antenna System In Rayleigh Fading Channels”, D. Bai, S. S. Ghassemzadeh, R. R. Miller, V. Tarokh.
R. R. Miller, AT&T