Throughput analysis of an asynchronous code division multiple access (CDMA) system
Abstract
This paper discusses the performance of a code division multiple access (CDMA) protocol in an asynchronous environment and compares the throughput of the asynchronous system implementation with that of the synchronous or slotted system. The simplest CDMA system, the one user capacity or Aloha, is known to degrade from 36 percent throughput with slotted implementation to 18 percent with asynchronous operation. It is shown that a system of capacity 35 simultaneous users decreases from 71 percent throughput in slotted implementation to only 60 percent in asynchronous implementation. The mathematical formulation for the asynchronous throughput is presented and verified by simulation. A simple expression for a lower bound is presented which can be used to determine approximately the maximum throughput for the asynchronous system.
- Publication:
-
ICC 1982 - The Digital Revolution, Volume 1
- Pub Date:
- 1982
- Bibcode:
- 1982icc.....1T...2M
- Keywords:
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- Channel Capacity;
- Code Division Multiple Access;
- Performance Prediction;
- Systems Simulation;
- Transmission Efficiency;
- Error Correcting Codes;
- Extremum Values;
- Probability Theory;
- Signal Encoding;
- Communications and Radar