Receiver for IEEE 802.11ah in Interference Limited Environments

Recently, IEEE 802.11ah standard has been proposed to extend the range of wireless local area network operating in the sub-1-GHz frequency band. This standard along with other protocols can provide communication services to the Internet of Things applications. However, in future, this band is also expected to be crowded like 2.45 GHz ISM band and cause interference to other devices operating in the same band. For a communication channel affected by additive white Gaussian noise, the least square (LS)-based estimator and Euclidean distance-based Viterbi decoder give optimal performance. However, the receiver's performance with LS estimator followed by the Viterbi decoder degrades for high interference affected communication channels. In this paper, a new orthogonal frequency division multiplexing-based receiver structure operating in high interference environment is proposed. The proposed receiver is based on nonparametric maximum likelihood channel estimation followed by Viterbi decoder. The Viterbi decoder's branch metric is updated based on the distribution of residual error. The proposed receiver structure is tested on IEEE 802.11ah-based receiver in two different type of additive interference: 1) IEEE 802.15.4 device and 2) impulsive noise. Both simulations and real-world experimental results on standard compliant platform show that the proposed algorithm performs better in terms of bit error rate than other receivers in all the considered interference models. Additionally, we also derive analytical expression for the probability of symbol error.