The capacity of mobile protocols such as FDMA (Frequency Division Multiple Access), TDMA (Time Division Multiple Access), and CDMA (Code Division Multiple Access) systems are compared assuming perfect power control and the results are compared with the previous results. Methods of calculating the traffic capacity of such systems are discussed. CDMA can provide up-to 20 times more traffic capaci...

Multiple users can be served by the same bandwidth in wireless CDMA systems of spread spectrum. The use can used the bandwidth and different codes at the same time and any signal showed by one of the user is seen as interference. This interference is detected to the base station in the process of extracting data used by a specific signal utilized by a user. Users who are closer to the BS are th...

Multiple users can be served by the same bandwidth in wireless CDMA systems of spread spectrum. The use can used the bandwidth and different codes at the same time and any signal showed by one of the user is seen as interference. This interference is detected to the base station in the process of extracting data used by a specific signal utilized by a user. Users who are closer to the BS are th...

A multiuser detector for direct-sequence code-division multiple-access systems based on particle swarm optimization (PSO) algorithm is proposed. To work around potentially computational intractability, the proposed scheme exploits heuristics in consideration of both global and local exploration maximum likelihood (ML). Computer simulation demonstrates that the proposed detector offers near-opti...

We present a combined orthogonal frequencydivision multiplexing (OFDM) and code-division multiple-access cellular system. It is derived from the OFDM model by introducing an extra code-shift division multiple access layer. This mitigates intercell interference without affecting intracell orthogonality and such property can be maintained in multipath environments. The new scheme is suitable for ...

The suitable use of an antenna array at the base station of a communication system results in improved Signal to Interference Ratio (SIR). In this paper, Linear Array (LA), Circular Array (CA) and Concentric Circular Antenna Array (CCAA) are used at the base station of a direct sequence code division multiple access (CDMA) systems. To suppress multiple access interference (MAI), the proposed sc...