Robust and Reliable Communication Meets Future Mobile Communication Demands

Robustness and reliability are more important for future applications than today. This is outlined in this paper. The suitability of the spread-spectrum technology for future wireless applications is investigated. The spread-spectrum technology offers the RAKE receiver structure to mitigate the most harmful type of interference in a mobile application, the multipath interference. To enhance the spectral efficiency multi-code transmission is employed. It is easy and inexpensive to adapt the system to the channel delay spread and avoid expensive channel equalization techniques. The extension from a point-to-point topology to a multipoint-to-point topology is achieved with the code-division-multiple-access concept. The bandwidth efficiency can be further enhanced using multi-user detection. For interference limited environments the multi-carrier code-division multiple access scheme is applied. Special attention is payed to the multi-code transmission and the related improvement in spectral efficiency.