Simulation Techniques for The QAM (2D) Code
Microcomputer-based simulation facilities, built to investigate the performance of bandwidth efficient quadrature amplitude modulation (QAM) type 2-dimensional codes, may be used to investigate the capacity of loop plants. Modulating techniques at baseband frequency are the QAM type, 2-dimensional (2-D) carrierless amplitude and phase or CAP modulation. There is no RF carrier (generally associated with QAM) per se in CAP. The CAP techniques are specifically important in the maximum utilization of available bandwidth. Data rates in copper media can thus be maximized to the full media capacity. In particular, these codes are likely to enhance the bidirectional data rates to T1 (1.544 Mbps in the United States) and to E1 (2.048 Mbps in Europe) in the subscriber loop plants. The extent and limitations are discussed in this Chapter. The feasibility of providing Basic Rate Integrated Services Digital Services (BRISDN at 144 kbps) in the various telephone environments is well documented with the 2B1Q code and is used as a benchmark (see Section 9.7.1) for the success or failure of the other more efficient modulating techniques.
KeywordsQuadrature Amplitude Modulation Trellis Code Loop Topology Cluster Noise Quadrature Amplitude Modulation Constellation
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- 9.2G.S. Moschytz and S.V. Ahamed 1991, “Optimization of the RC Matching Network in Adaptive Active Hybrids for High Speed Data Communications”, Proceedings of the IEEE International Symposium on Circuits and Systems, Singapore, June, 2741–2744Google Scholar
- 9.4M. Sorbara, J.J. Werner, and N.A. Zervos 1990, “Carrierless AM/PM”, Contribution T1E1. 4/90–154, SeptemberGoogle Scholar
- 9.5M.J. Miller and S.V. Ahamed 1988, Digital Transmission Systems and Networks, Volume II: Applications, Computer Science Press, Rockville, MD.Google Scholar
- 9.6A. Elrefaie, M. Romeiser 1986, “Computer Simulation of Single-mode Fiber Systems”, Conference Record, Optical Fiber Communications Conference, February, 54–56Google Scholar
- 9.8K.S. Shanmugan, et.al. 1985, “Simulation of Digital Lightwave Communication Links Using SYSTID”, Record of Globecom 85, DecemberGoogle Scholar