Performance analysis of orthogonal complementary code based Offset-Stacking UWB system

In this paper, the orthogonal complementary code (OCC) based ultra wideband (UWB) system with Offset-Stacking (OS) spreading modulation is investigated. OCC has perfect partial autocorrelation and cross-correlation characteristics. The application of OCC in UWB system can offer the elimination of the multiple access interference (MAI) in both synchronous and asynchronous transmissions over AWGN channel. The proposed UWB architecture can achieve variable data rate transmission due to its innovative offset stacking spreading technique. Theoretical analysis illustrates that multipath interference (MPI) as well as MAI can be alleviated over lognormal multipath fading channels in OS OCC-UWB system. Our simulation also shows the superiority of the OCC based OS-UWB system to unitary code based DS-UWB systems.

I. Introduction

Ultra-wideband (UWB) technology was proposed in 1960s and has attracted much attention of the scholars and researchers all over the world in recent years. Federal Communication Commission (FCC) has regulated that the bandwidth allocated for UWB is 7.5GHz, from 3.1GHz to 10.6GHz. The merits of UWB technology such as high data rate, low cost, low power spectrum density and good resistance to severe multipath interference, etc, make it an attractive technology for short-range high speed wireless communications. However, in UWB system, multiple access interference (MAl) is an important factor that affects the system performance with the increase of the user number. Theoretical analysis of bit error rate for multiple access UWB systems have been discussed in many literatures [1]–[3]. [4] investigated the analysis of multi-user interference of the three different families of unitary codes, such as i.i.d, Gold and Kasami sequences, in asynchronous direct sequence ultra-wideband (DS-UWB) system. It was shown that the system performance could be better with good spreading sequences. [5]–[6] proposed ternary complementary code sets based UWB system which could alleviate multipath interference (MPI) and MAl and [7] studied the application of multilevel complementary sets of sequences in UWB system.