tailieunhanh - Adaptive thu phát không dây P5

In the previous chapter, introduced the joint Adaptive Quadrature Amplitude Modulation we (AQAM) and equalization scheme, where the pseudo-SNR outputof the DFE was used at the as the modulation mode switching metric in order to mitigate the effectsa wideband fading of AQAM scheme is extended to incorporate benefits the channel. In this chapter, the wideband of channel coding. The general motivation for using channel coding is to exploit the error correction and the error detection capability the channel codes order to improve the of in BER of and throughput performance the wideband AQAM scheme | Adaptive Wireless Tranceivers L. Hanzo . Wong . Yee Copyright 2002 John Wiley Sons Ltd ISBNs 0-470-84689-5 Hardback 0-470-84776-X Electronic Chapter Turbo-Coded and Turbo-Equalised Wideband Adaptive Modulation In the previous chapter we introduced the joint Adaptive Quadrature Amplitude Modulation AQAM and equalization scheme where the pseudo-SNR at the output of the DFE was used as the modulation mode switching metric in order to mitigate the effects of a wideband fading channel. In this chapter the wideband AQAM scheme is extended to incorporate the benefits of channel coding. The general motivation for using channel coding is to exploit the error correction and the error detection capability of the channel codes in order to improve the BER and throughput performance of the wideband AQAM scheme. As we have shown in Chapter 4 the wideband AQAM scheme was capable of yielding an improved BER and BPS performance when compared to each individual fixed modulation mode. Since the wideband AQAM scheme improves the BER performance high coding rate channel codes can be utilized in our coded AQAM scheme. The utilization of these high coding rate channel codes is essential to produce a better coded throughput performance when compared to the uncoded wideband AQAM scheme which was discussed in the previous chapter. Since the wideband AQAM scheme always attempts to invoke the appropriate modulation mode in order to combat the wideband channel effects the probability of encountering a received transmitted burst with a high instantaneous BER is low when compared to the constituent fixed modulation modes. This characteristic is advantageous since due to the less bursty error distribution the coded wideband AQAM scheme can be implemented without the utilization of high-delay channel interleavers. Consequently we can exploit the error detection capability of the channel codes almost instantaneously at the receiver for every received