1. Adaptive rate control Requirements
July 2005
July 2005
July 2005
Adaptive rate control Requirements
Date:
Authors:
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Feng Li, ZTE Corporation
Feng Li, ZTE Corporation

2. July 2005
July 2005
July 2005
Abstract
The objective of this document is to recommend the requirements of the adaptive rate control in WLAN to TGv.
Feng Li, ZTE Corporation
Feng Li, ZTE Corporation

3. Agenda Pros/Cons of current transfer rate control Recommendations
July 2005
July 2005
July 2005
Agenda
Pros/Cons of current transfer rate control
Recommendations
Rationale for adaptive rate control
Text proposal
Feng Li, ZTE Corporation
Feng Li, ZTE Corporation

4. Pros/Cons of current transfer rate control (1/2)
July 2005
Pros/Cons of current transfer rate control (1/2)
Data transfer rate is fixed during each frame sequence exchange. Little channel quality information is transmitted between the transmitter and receiver before the transmission.
Feng Li, ZTE Corporation

5. Pros/Cons of current transfer rate control (1/2)
July 2005
Pros/Cons of current transfer rate control (1/2)
Advantages:
Simple control, low overhead, low cost
Disadvantages:
Not time-varying mobile channel adaptive
- due to the relative fixed transfer rate
Inaccurate evaluation of channel quality
- due to poor knowledge in the forward channel quality. Unsuitable for the case of different forward/backward channel quality
latency in statistical evaluation of channel quality
- Impossible to response quickly to the fast and abrupt changing channel.
poor performance of whole network
- Mismatch of data transfer rate with the quality of channel, which may lead to high frame error rate, long latency, low throughput
Feng Li, ZTE Corporation

6. Recommendations Practice scenario:
July 2005
Recommendations
Practice scenario:
Spectrum usage
Wireless mobile environment
Sophisticated environments
RF management
MIMO
VoWLAN
Hot spot
Suggest the consideration of adaptive rate control in the requirement of TGv
Feng Li, ZTE Corporation

7. Rationale for adaptive rate control
July 2005
Rationale for adaptive rate control
Definition of adaptive rate control:
Traffic transfer rate is able to be adjusted adaptively to be more appropriate according to real channel quality.
What can we get from adaptive rate control:
Robustness of traffic transaction. QoS of traffic transaction can be guaranteed once the STA obtain a transmission opportunity (TXOP).
Improvement of the FER performance in case of poor channel quality by adaptively reducing the data transfer rate.
Enhancement of the spectrum usage by adaptively optimizing the transfer rate.
Improvement of the network efficiency, with higher throughput and lower latency, and increase of the mobility of STA.
Feng Li, ZTE Corporation

8. July 2005
Text proposal to TGv
During the process of frame sequence exchange, the STA should be able to adjust the transfer rate correspondingly based on the channel quality information received.
Advantages:
- Adaptive rate control has more superior than fixed rate control in case of wireless mobile channels
- Adaptive rate control based on segments during frame sequence exchange offers reliable data transmission
- Adaptive rate control enhances network efficiency
- Accurate channel quality measurement is able to be obtained based on forward channel quality evaluation
- Adaptive rate control is more suitable in the case of different forward/backward channel quality.
Disadvantages:
- Additional scheduling complexity and network overhead
Feng Li, ZTE Corporation

9. July 2005
Feedback!
Feng Li, ZTE Corporation