Header Compression Date: 2012-05-13 Authors: May 2012 Month Year doc.: IEEE 802.11-yy/XXXXr0 May 2012 Header Compression Date: 2012-05-13 Authors: Shoukang Zheng et. al, I2R, Singapore Shoukang ZHENG et. al, I2R, Singapore

Month Year doc.: IEEE 802.11-yy/XXXXr0 May 2012 Abstract In this contribution, we present the scheme to compress the dynamic fields in MAC header in 802.11ah. Shoukang Zheng et. al, I2R, Singapore Shoukang ZHENG et. al, I2R, Singapore

May 2012 Motivation In 802.11ah use cases, low data rate requires header compression for efficient transmission. Constant fields in MAC header can be compressed MAC address Constant in the Control fields Dynamic fields in the header may be also compressed Sequence number PN (packet number) in CCMP header Shoukang Zheng et. al, I2R, Singapore

May 2012 Problems Header compression protocol must be simple with small overhead Proposed scheme [1] uses some management exchange to set up the context for compression. Other method is suitable as well. How to compress the dynamic field compression efficiently? Shoukang Zheng et. al, I2R, Singapore

Suggested Solution Compression/Decompression Context Setup Compression May 2012 Suggested Solution Compression/Decompression Context Setup Initial value as the base for dynamic field The range of compressed value is [0,Vmax] Compression Use fewer bits Only compressed value (bits) is transmitted after context setup # of compressed bits: log2(Vmax+1) Decompression Compressed value + Initial value Context Update Re-synchronize the initial value of dynamic field Shoukang Zheng et. al, I2R, Singapore

Dynamic Field Compression May 2012 Dynamic Field Compression Sequence Number (12 bits) Use fewer bits (e.g. 4 bits) for low data rate PN0-5 fields in CCMP header Use fewer bits (e.g. 4 bits) PN incremental value fixed as 1 (highest compression ratio) Shoukang Zheng et. al, I2R, Singapore

Synchronizing Context May 2012 Synchronizing Context When compression side detects that decompression is out of synchronization on initial value of dynamic field, compression side can update the context When decompression side detects that it is out of synchronization on initial value of dynamic field, decompression side can request to update the context Shoukang Zheng et. al, I2R, Singapore

May 2012 Conclusions We propose to support dynamic field compression for MAC header Shoukang Zheng et. al, I2R, Singapore

May 2012 References [1] “Frame Header Compression”,11-12-0110-06-00ah-frame-headercompression.pptx [2] “MAC Header Compression”, 11-12-0369-01-00ah-mac-headercompression.pptx Shoukang Zheng et. al, I2R, Singapore

May 2012 Straw Poll (1) Do you agree that dynamic field (sequence number and PN0-5 fields) can be compressed as in slide 5? Y: N: A: Shoukang Zheng et. al, I2R, Singapore

May 2012 Straw Poll (2) Do you agree that sequence number field can be compressed as in slide 6? Y: N: A: Shoukang Zheng et. al, I2R, Singapore

May 2012 Straw Poll (3) Do you agree that PN (packet number) in CCMP header can be compressed as in slide 6? Y: N: A: Shoukang Zheng et. al, I2R, Singapore