Implementation of a Fast Link Rate Adaptation Algorithm for WLAN Systems

Abstract

With a target to maximize the throughput, a fast link rate adaptation algorithm for IEEE 802.11a/b/g/n/ac is proposed, which is basically preamble based and can adaptively compensate for the discrepancy between transmitter and receiver radio frequency performances by exploiting the acknowledgment signal. The target system is a 1 × 1 wireless local area network chip with no null data packet or sounding. The algorithm can be supplemented by automatic rate fallback at the initial phase to further expedite rate adaptation. The target system receives wireless channel coefficients and previous packet information, translates them to amended signal-to-noise ratios, and then, via the mean mutual information, selects the modulation and coding scheme with the maximum throughput. Extensive simulation and wireless tests are carried out to demonstrate the validity of the proposed adaptive preamble-based link adaptation in comparison with both the popular automatic rate fallback and ideal link adaptation. The throughput gain of the proposed link adaptation over automatic rate fallback is demonstrated over various packet transmission intervals and Doppler frequencies. The throughput gain of the proposed algorithm over ARF is 46% (15%) for a 1-tap (3-tap) channel over 10 m–250 m (16 m–160 m) normalized Doppler frequencies. Assuming a 3-tap channel and 30 m–50 m normalized Doppler frequencies, the throughput of the proposed algorithm is about 31 Mbps, nearly the same as that of ideal link adaptation, whereas the throughput of ARF is about 24 Mbps, leading to a 30% throughput gain of the proposed algorithm over ARF. The firmware is implemented in C and on Xilinx Zynq 7020 (Xilinx, San Jose, CA, USA) for wireless tests.

An Application of Throughput Request Satisfaction Method for Maximizing Concurrent Throughput in WLAN for IoT Application System

“…In [17], Park et al introduced a rapid link rate adaptation algorithm for WLAN, emphasizing its design and implementation. This algorithm enables swift adjustment of the transmission rate in response to variations in channel conditions, such as signal strength or interference.…”

Environment-Aware Rate Adaptation Based on Occasional Request and Robust Adjustment in 802.11 Networks

“…Rate adaptation algorithms based on the receiving end include OAR, RBAR, RARA, and so on. Although these algorithms can theoretically obtain more accurate reference data, additional feedback mechanisms are needed to transmit this information to the sender [ 24 ]. Usually, CTS frames or ACK frames are used to transmit feedback information, and it is generally necessary to modify the IEEE 802.11 standard frame structure.…”

DRLLA: Deep Reinforcement Learning for Link Adaptation

“…Improving the performance of LA algorithms is a very relevant problem and has spawned increasing interest in research over the past few years. In a recent paper, Park et al propose an algorithm that chooses MCSs based on the received channel coefficients and previous packet information [7]. These metrics are translated to SNR values, which are used to derive an MCS with preferably high throughput.…”