Academic literature on the topic 'Square Root Raised Cosine Filtering (SRRC)'

Abstract In this paper we propose a discrete-time FIR (Finite Impulse Response) filter which is meant to be applied as a square root Nyquist filter and fractional delay filter simultaneously. The filter enables to substitute for a cascade of square root raised cosine (SRRC) Nyquist filter and fractional delay filter in one device/algorithm. The aim is to compensate for transmission delay in digital communication system. Performance of the filter in the role of a matched filter is evaluated using a newly defined energetic ISI (Intersymbol Interference) measure and ability of the filter to completely eliminate the ISI involved by fractional delay of symbol shaping filter in transmitter or by channel delay. Considerations and results of the contribution are documented by suitable eye-diagrams and the SRRC filter responses.

Polyphase FIR filters are applied in many practical Digital Signal Processing applications where the sampling rate needs to be changed. This paper focuses on the implementation of polyphase square root raised cosine (SRRC) FIR filter based on Field Programmable Gate Array (FPGA). The filter employs methods like filter's multiphase structure, symmetrical coefficients, I/Q channel multiplexing, pipeline addition and so on to design the SRRC filter. Compared with the traditional method, the designed FIR filter exhibits the advantages of high response speed and low hardware resource s consumption.

Acceptable Quality of Service (QoS) is of paramount importance in wireless communication system. However, QoS is affected by multipath propagation resulting in unreliable reception. Selection Combiner (SC) which is one of the techniques previously used to solve this problem is associated with poor performance due to fixed power level used in the technique. Hence, in this paper, an Adaptive Power Control (APC) technique using SC with a closed form expression over Nakagami-m Fading Channel is proposed. APC technique is developed using fixed power SC and Link Adaptation Algorithm (LAA). Ten thousand (10,000) bits are randomly generated and modulated using Quadrature Amplitude Modulation (QAM) scheme. The modulated signal is passed through the Square Root Raised Cosine (SRRC) filter for suitable transmission over the Nakagami-m fading channel. The faded signals at varying paths ‘L’ (2, 3, 4) are selected by Conventional Selection Combining (CSC) to instruct the transmitter for adjustment of power level based on the value of the received signal through LAA. Mathematical expression for the received signal using Probability Density Function (PDF) of Nakagami-m Fading Channel at varying paths is derived. The APC technique is simulated using MATLAB software and evaluated using Signal to Noise Ratio (SNR), Outage Probability (OP) and Bit Error Rate (BER) to determine the performance of the proposed technique. OP values of 0.0969 and 0.1069 are obtained for APC and CSC, respectively, at SNR of 6 dB with L of 4, while BER values of 0.0052 and 0.2599 are obtained for APC and CSC, respectively. The percentage reduction in OP and BER are 29.79% and 54.43%, respectively. The results obtained show that APC gives lower OP and BER values with increase in SNR when compared with fixed power SC due to self-adjustment of the allocated power. Therefore, the APC technique proposed can be used to enhance the performance of wireless communication systems. Keywords— Adaptive Power Control (APC), Selection Combiner (SC), Link Adaptation Algorithm (LAA), Bit Error Rate (BER), Outage Probability (OP), Probability Density Function (PDF) and Diversity Combiner (DC).

International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California
As frequency allocation restrictions are tightening, and data rates are increasing, it is becoming necessary to incorporate higher order modulation techniques to make more efficient use of available spectrum. When used with Square Root Raised Cosine filtering, 8-ary Phase Shift Keyed modulation is a spectrally efficient technique that makes better use of today’s RF spectrum in comparison to standard formats. This paper will discuss 8-ary PSK modulation and its spectral efficiency with a SRRC filter, along with comparisons to BPSK, QPSK, and FSK.