Rapid equalisation for a high integrity bluetooth receiver

The Bluetooth standard has a lax specification for parameters such a carrier frequency and modulation index. Research has shown that significant system degradation can occur even when operating within the permitted limits. Hence, a high-integrity Bluetooth receiver will need to compensate for this mismatch. Where multipath propagation exists, it will undermine parameter synchronizing algorithms, and taking into account the limited burst lengths of Bluetooth packets, it is essential that equalization occurs fast enough so as to give algorithms downstream sufficient time to converge, and minimize information loss. The coloured nature of Bluetooth signals and the possibility of a earner frequency offsets, limit the choice of equalizer algorithms that can guarantee fast convergence. As a remedy, in this paper we propose the normalized sliding window constant modulus algorithm (NSWCMA). and determine regularization factors that will optimize speed. We also show that the NSWCMA can outperform the minimum mean square error solution in terms of bit error ratio