Shortened transmit technique removing zeros from repetition in the frequency domain for OFDM systems

Abstract

This paper proposes a shortened transmit technique using repetitive transmission in the frequency domain. For a single antenna OFDM system, a hybrid selection combining and maximum ratio receive combining technique was proposed for better performance, but it is effective only for high Eb/N0 region. This paper suggests a new method of removing zeros generated from repetitive transmission and of reconfiguring repetitive transmit time domain signals for maximum ratio receive combining at the receiver, by which we can obtain better performance comparing to SISO case at the expense of a few algebraic calculations and FFT/IFFT executions.

Hybrid STT/ERT and SC-FDE technique for single carrier transmission with a guard period

“…1 (a). STT/ERT scheme is known to have frequency diversity gain [4], and the performance is improved by increasing the number of symbol repetition. If we maximize it as the number of subcarriers, the transmitter becomes a single-carrier transmitter as follows.…”

“…Orthogonal frequency division multiplexing (OFDM) system has been known to be effective for wireless local area networks [1], and its combination of technologies, such as selection combining and maximum ratio receive combining (MRRC), have been developed [2,3]. Among repetitive transmission methods in the frequency domain, we recently proposed a shortened transmission technique (STT) for removing time domain zeros generated from repetitive transmission and obtaining MRRC gain while expanding reception technique (ERT) in the receiver [4], but it has a channel restriction of an exponentially decaying and static profile. This paper suggests using a modified ERT which consists of a sequential deconvolution with a decision and remodulation algorithm, in order to adapt it to dynamic channel environments.…”