Design of a new time orthogonal multiuser line code

The design of a new multiuser line-coding scheme based on ideas from collaborative coding multiple access (CCMA) is presented. The new scheme yields good throughput in terms of user information bits per time slot (baud). Separate user data streams (or a single data stream demultiplexed into multiple separate streams) are combined in a binary adder channel. Trade-offs among the number of users, number of time slots per user symbol, and number of user information bits per user symbol are developed, and possible codes are tabulated. A maximum rate of 4.4 bits/baud can be achieved by using five time slots, with two symbols/user and 22 users.