A proposal of single carrier beam tracking communications systems for low power 60GHz indoor wireless communications terminals

Abstract

In order to realize lower power consumption multi-Gbps communications terminals in 60 GHz, this paper proposes a single carrier with FEC (Forward error correction) communications system together with a beam tracking and switching receiver antenna. In the proposed system, communications path will be switched from the LOS (line of sight) path to one of the best S/N path when the LOS path is interrupted by a moving object such as human body and continue the communications. The advantage of the proposed system is to have smaller delay spread that will make no necessity of OFDM (Orthogonal Frequency Division Multiplexing) as a tool to mitigate huge delay spread which is commonly observed in WLAN (Wireless LAN) systems. To validate the proposed system, this paper took the channel models created by IEEE802.15.3c std. in that TX and RX antennas are facing each other and reflected waves are received from all directions (360 degrees) at the RX antenna. The difference created on top of the TG3c channel model is to track and switch the RX antenna to the best S/N reflected wave when the system lost the LOS path. In this way, much smaller delay spread is expected in the proposed system which will lead to no necessity of OFDM signal transmission. The computer simulation results show bit error rate performances of the proposed system has very little degradation by applying strong FEC of “convolutional encoding and Viterbi decoding”, leading to potential necessity of equalizer for further bit error rate improvement but no necessity of OFDM signal transmission. Thus, the proposed system is good for multi-Gbps transmission over low power consumption portable terminals in 60 GHz.