Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
Tải xuống
CDMA packet radio networks 11.1 DUAL-CLASS CDMA SYSTEM In this chapter we consider some additional details of packet transmission in a Code Division Multiple Access (CDMA) radio network. The approach is very much based on Reference [1]. We start with dual-class traffic and then extend the analysis to multimedia systems. These two classes are characterized by the following set of parameters: Class 1: The users in this class are delay intolerant. When transmitting information, they require support for a constant bit rate of R1 bit s−1 ; they can tolerate a bit error rate (BER) of at most Pb1 . Class 2:. | Adaptive WCDMA Theory And Practice. Savo G. Glisic Copyright 2003 John Wiley Sons Ltd. ISBN 0-470-84825-1 11 CDMA packet radio networks 11.1 DUAL-CLASS CDMA SYSTEM In this chapter we consider some additional details of packet transmission in a Code Division Multiple Access CDMA radio network. The approach is very much based on Reference 1 . We start with dual-class traffic and then extend the analysis to multimedia systems. These two classes are characterized by the following set of parameters Class 1 The users in this class are delay intolerant. When transmitting information they require support for a constant bit rate of R1 bit s-1 they can tolerate a bit error rate BER of at most Pb1. Class 2 The users in this class are delay tolerant. When transmitting information they require support for a bit rate of at least Rmin bit s-1 they can tolerate a BER of at most Pb2. When not transmitting information it is assumed that the users still communicate with the base for synchronization purposes. The bit rate used in this synchronization mode is denoted as Ro bit s-1 and is referred to as the idle rate . One would expect that Ro R1 Ro Rmin more detailed constraints on Ro are given later. In an actual system Classes 1 and 2 could represent voice and data users respectively. Minimum rate Ro would be used in a control channel. According to equation 10.10 a unique solution to a minimum total transmit power problem exists if and only if E i 1 1 1 W _ _ A W _ _ A W SIR R 2 SIR IW 1-------------------- minjr ht ---W-- 1 4L AR SIRi N1 N2 i 1 11.1 370 CDMA PACKET RADIO NETWORKS By using the following notation h1 mobile to base gain of the ith generic user SIR 1 i constant V Class 1 users i SIR y1 BER Pb1 SIR-2 2 constant V Class 2 users i SIR Y2 BER Pb2 minimum total transmit power solution is obtained from equation 11.1 for minimum required rate Rmjn.Pipeak œVi constraint 11.1 now becomes N N2max -E- 1 _E_ 1 R1 Y1 Rmin Y2 1 11-2 Given that N Class 1 users are present one may .