Title
Fine-grained channel access in wireless LAN
Abstract
Modern communication technologies are steadily advancing the physical layer (PHY) data rate in wireless LANs, from hundreds of Mbps in current 802.11n to over Gbps in the near future. As PHY data rates increase, however, the overhead of media access control (MAC) progressively degrades data throughput efficiency. This trend reflects a fundamental aspect of the current MAC protocol, which allocates the channel as a single resource at a time. This paper argues that, in a high data rate WLAN, the channel should be divided into separate subchannels whose width is commensurate with PHY data rate and typical frame size. Multiple stations can then contend for and use subchannels simultaneously according to their traffic demands, thereby increasing overall efficiency. We introduce FICA, a fine-grained channel access method that embodies this approach to media access using two novel techniques. First, it proposes a new PHY architecture based on OFDM that retains orthogonality among subchannels while relying solely on the coordination mechanisms in existing WLAN, carrier-sensing and broadcasting. Second, FICA employs a frequency-domain contention method that uses physical layer RTS/CTS signaling and frequency domain backoff to efficiently coordinate subchannel access. We have implemented FICA, both MAC and PHY layers, using a software radio platform, and our experiments demonstrate the feasibility of the FICA design. Further, our simulation results suggest FICA can improve the efficiency ratio of WLANs by up to 400% compared to existing 802.11.
Year
DOI
Venue
2010
10.1145/1851182.1851202
SIGCOMM
Keywords
Field
DocType
mac,ofdma,cross-layer,fine-grained channel access
Broadcasting,Media access control,Computer science,Computer network,Communication channel,Physical layer,Throughput,PHY,Orthogonal frequency-division multiplexing,Channel access method
Conference
ISSN
Citations 
PageRank 
19435819
106
5.35
References 
Authors
20
7
Search Limit
100106
Name
Order
Citations
PageRank
Kun Tan1135098.64
Ji Fang253538.62
Yuanyang Zhang322010.19
Shouyuan Chen41869.98
Lixin Shi530120.26
Jiansong Zhang659648.98
Yongguang Zhang73461248.65