Robust and Reliable Communication Meets Future Mobile Communication Demands

Abstract

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 multiuser detection. For interference limited environments the multicarrier code-division multiple access scheme is applied. Special attention is payed to the multi-code transmission and the related improvement in spectral efficiency.

Low-Complex Reliable Communications between Wireless Network-Nodes

“…The exploitation of nonlinear interference reduction processing in addition to the robust nature of the spread-spectrum technology was investigated in [24], [25], [26], [27], [28], [29], [1]. The adaptation of the characteristic of an analog memoryless nonlinearity to the behavior of the unwanted signal, for non spread-spectrum systems, was investigated by Higbie in [32].…”

“…The disadvantage of wireless is its air-interface, which is subject to any electromagnetic interference. Especially in industrial applications it is desirable to use robust schemes to establish reliable links [1]. To achieve this goal for digital communications, we suffer from the so called capture-effect, which is specific for low-complex digital philosophies and degrades the performance significantly.…”

“…So it is a blind scheme. The advantages of blind-schemes are: (1) No channel estimates are necessary, avoiding estimation-errors, avoiding adaptation problems in high dynamic interference environments. (2) Needs no return channel to the transmitting node.…”