Cognitive radios (CRs) operating in a frequency band owned by a legacy wireless communication system (often called the primary system) can be made more efficient if interference from the primary system is exploited instead of being regarded as a major disturbance that limits the opportunity to reuse the primary frequency band, However, since the primary system is a legacy system with known transmission parameters, the interference from the primary system should not always be treated as Gaussian-like noise. For a time-division- duplexing-based primary system, we show two examples of interference exploitation: (1) exploitation in the medium access control (MAC) layer to achieve distributed medium access for collocated CR networks (exploitation in the time domain) and (2) exploitation in the physical (PHY) layer where the interference from/to the primary system is cancelled/mitigated by using an adaptive array antenna (exploitation in the spatial domain). We show that such exploitation of interference can help cognitive radios efficiently reuse the primary spectrum in space and time.
|ジャーナル||NTT Technical Review|
|出版物ステータス||Published - 2007 10 1|
ASJC Scopus subject areas
- Computer Science Applications
- Computer Networks and Communications
- Electrical and Electronic Engineering