Joint optimization of transmit pulse shaping, guard interval length, and receiver side narrow-band interference mitigation in the HomePlugAV OFDM system

The primary subject of this paper is the selection of a pulse-shaping waveform for in-home power line communications. As system performance is also determined by other parameters affecting the length and shaping of the OFDM symbol, the problem formulation is expanded to also include the simultaneous selection of guard interval length and Hanning window length, creating a joint optimization problem. Given the constraints of allowing no transmit notch filters, and adequate receive side mitigation of narrow band jammers, we jointly optimize the selection of guard interval length, transmit pulse-shaping and receive side windowing for throughput performance on the average power line channel. Throughput performance is inferred from SNR data and associated guard interval overhead. We also present results of performance assessment and parameter selection, for the average power line channel, based on a collection of 120 measured power line channel impulse responses.

1. INTRODUCTION

One of the features that made Orthogonal Frequency Division Multiplexing (OFDM) such a popular choice among communication system designers, is that its multi-carrier nature gives it the ability to easily adapt in frequency. This frequency domain adaptability is exploited both in a dynamic sense, where given a frequency selective channel, an OFDM system can concentrate its efforts on those frequency ranges that yield the highest SNRs, and it can also be exploited in a static manner: for example, when a contiguous band of frequencies is not available, OFDM allows the communication system to efficiently use the frequencies where communication is possible.