Performance of High Order Modulation Scheme in OFDM-UWB 60 GHz System

Abstract

The emerging trends of wireless communication and ever growing demand of very high data rate from users created the need for new technologies that could satisfy this need under limited bandwidth. A 60-GHz Ultra-Wideband (UWB) system that can support up to 7 Gbps data rate, which is 10 times faster than the data rate of the Wi-Fi 802.11n, is one of the promising options. The system utilizes higher order modulation and advanced coding schemes known as Adaptive Modulation and Coding (AMC). However, inappropriate selection of modulation level and coding rate can lead to low data rate particularly in the presence of Radio Frequency interference and multipath fading. Moreover, further performance degradation occurs when non-optimal decoder due to code constraint length was selected. This paper proposes and evaluates a duplex 60-GHz UWB system employing Orthogonal Frequency Division Multiplexing (OFDM-UWB) to boost the data rate and extend the coverage. Firstly, an OFDM-UWB system employing high order modulation that transmits data simultaneously over multiple carriers spaced apart at precise frequencies been simulated and validated using Matlab. Secondly, the system performance been analyzed when convolutional coding been introduced in term of Bit Error Rate (BER). The simulation results show that the BER performance of 16QAM is worse, with 6 dB penalties at BER of 10−3, compared with that of QPSK. Moreover, simulation also shows that there are 2 dB difference between the performance of R=1/2 and R=7/8, while the highest throughput been achieved when the 3/4 code rate is employed.