A New Low Complexity Uniform Filter Bank Based on the Improved Coefficient Decimation Method

In this paper, we propose a new uniform filter bank (FB) based on the improved coefficient decimation method (ICDM). In the proposed FB’s design, the ICDM is used to obtain different multi-band frequency responses using a single lowpass prototype filter. The desired subbands are individually obtained from these multi-band frequency responses by using low order frequency response masking filters and their corresponding ICDM output frequency responses. We show that the proposed FB is a very low complexity alternative to the other FBs in literature, especially the widely used discrete Fourier transform based FB (DFTFB) and the CDM based FB (CDFB). The proposed FB can have a higher number of subbands with twice the center frequency resolution when compared with the CDFB and DFTFB. Design example and implementation results show that our FB achieves 86.59% and 58.84% reductions in resource utilizations and 76.95% and 47.09% reductions in power consumptions when compared with the DFTFB and CDFB respectively

VLSI Implementation of Energy Detection Algorithm for WLAN and WiMAX Applications

The electromagnetic spectrum is a natural resource. The current spectrum licensing scheme is unable to accommodate rapidly growing demand in wireless communication due the static spectrum allocation policies. This allocation leads to increase in spectrum scarcity problem. Cognitive radio (CR) technology is an advanced wireless radio design which aims to increase spectrum utilization by identifying unused and under-utilized spectrum in dynamically changing environments. Spectrum sensing is a one of the key method of cognitive radio which detects the presence of primary user in licensed frequency band using dynamic spectrum allocation policies to utilize unused spectrum. Energy detection is a simple spectrum sensing technique, which does not require prior information of signal which is present in the frequency band. But in low signal to noise ratio (SNR) conditions, its performance is weak, which can be improved by signal processing algorithm. As energy detection is simple and easily implemented in hardware, so it is preferred in emerging standard like IEEE 802.22, Wireless Region Area Network (WRAN), IEEE 802.11a,Wireless Local Area Network(WLAN) and 802.16, World Wide Interoperability Microwave Access(WiMAX). In this thesis energy detection technique is applied for WLAN and WiMAX under BPSK modulation method and Monte-Carlo simulations are performed totest the performance of received signals in WLAN and WiMAX. Following to this work VLSI implementation of spectrum sensing using energy detection have been implemented for pseudo random sequence generated signal and BPSK modulates signal. OFDM is used as modulation standard and it is implemented in VLSI for WLAN and WiMAX