AGILE Rate Control for IEEE 802.11 Networks

Abstract

Abstract. We present a transmission rate adaptation algorithm called AGILE (ACK-Guided Immediate Link rate Estimation) for IEEE 802.11 networks. The key idea of AGILE is that the transmitter adjusts the transmission rate by means of measuring the SNR (Signal-to-Noise Ratio) during any frame reception including the ACK (Acknowledgment) frame, and estimating the corresponding maximum achievable throughput using a profile, which is materialized by extensive off-line measurement. AGILE is equipped with an advanced RTS (Request-To-Send)/CTS (Clear-To-Send) activation algorithm, eRTS filter that intelligently switches on/off RTS frame transmission to enhance the achievable throughput depending upon the existence of multiple contending (or even hidden) stations. The effectiveness of AGILE is evaluated in our MadWifi-based testbed implementation and we compare its performance with different rate adaptation schemes in various scenarios.

REACT: Rate Adaptation using Coherence Time in 802.11 WLANs

“…For example, although [1][2][3] presume that successive transmission failures are due to poor channel conditions, frame losses can also be caused by interference from hidden stations or collisions [4,7,16,17,19,20]. Moreover, although [8][9][10][11][12] assume that the wireless link between the transmitter and receiver is symmetric, it has been known that wireless links are highly asymmetric [21,22], especially in indoor environments [23].…”

“…Each scheme has its own heuristic algorithm to exploit the MAC layer statistics for estimating a channel such as maintaining consecutive success/failure counters [1][2][3][4][5], estimating an expected transmission time for each bit rate [6], calculating a frame loss ratio for recent trials [7], and so on. Other schemes in this category decide the transmission rate based on the local physical layer measurement which is done while ACK frames are received [8][9][10][11][12].…”

“…Vendors and researchers have introduced a number of proposals as the 802.11 standards do not mandate the procedures of selecting the transmission rate [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], which are collectively referred to as the rate adaptation. In principle, the higher is the received signal-to-noise ratio (SNR), the higher transmission rate can be used for communications.…”

Selective Frame Transmission for QoS provisioning in IEEE 802.11 networks

“…ARF adapts the transmission rate with wireless medium fluctuation and represents the best case for SFT algorithm, with minimum W aitingT ime for each frame. We use ARF as an example to show the effect of appropriate rate selection on the SFT algorithm, however selecting an appropriate transmission rate is an orthogonal issue and many algorithms have been proposed in literature addressing this issue [15], [17]- [20].…”