Final Report Summary - WISERNETS (Wireless sensor networks for cognitive software radios)
The increasing demand for higher data rates in wireless communications in limited or under-utilised spectral resources has motivated the introduction of cognitive radio (CR). The basic idea of CR is that a terminal with cognitive capabilities can exploit the underutilised spectral resources without interfering with primary users which have the priority to use the licensed spectral resources.
In this project, we studied a spectrum cartography (SC) approach for CR where the wireless terminals evaluate transmission opportunity for local or cooperative communications coexisting with traditional communication between terminals and basestation (BS). We proposed a SC approach where the CR terminals ?rst collaborate with a wireless sensor network to estimate the spectrum map using a distributed kriging algorithm based on the exploitation of the spatial correlation of the power distribution on a determined area. Afterwards the CR terminals consult the maps and optimise its local communications, i.e. bypassing the BS for a mobile-to-mobile communications or enabling cooperative communications.
We studied also the so-called underlay scenario where we decided to use ultra-wideband (UWB) technology to keep the transmission power of secondary users below the noise ?oor of primary users. In this case it is not necessary detection information but the main problem is to control the multi-user interference generated by other UWB cognitive users that access the network at the same time and in the same area. This interference can signi?cantly degrade the performance of the cognitive users. We proposed a mutual-information based rate adaptation technique that allows to guarantee a ?xed quality of service (QoS).
The proposed algorithms are being tested with universal software radio peripheral (USRP) technology.
In this project, we studied a spectrum cartography (SC) approach for CR where the wireless terminals evaluate transmission opportunity for local or cooperative communications coexisting with traditional communication between terminals and basestation (BS). We proposed a SC approach where the CR terminals ?rst collaborate with a wireless sensor network to estimate the spectrum map using a distributed kriging algorithm based on the exploitation of the spatial correlation of the power distribution on a determined area. Afterwards the CR terminals consult the maps and optimise its local communications, i.e. bypassing the BS for a mobile-to-mobile communications or enabling cooperative communications.
We studied also the so-called underlay scenario where we decided to use ultra-wideband (UWB) technology to keep the transmission power of secondary users below the noise ?oor of primary users. In this case it is not necessary detection information but the main problem is to control the multi-user interference generated by other UWB cognitive users that access the network at the same time and in the same area. This interference can signi?cantly degrade the performance of the cognitive users. We proposed a mutual-information based rate adaptation technique that allows to guarantee a ?xed quality of service (QoS).
The proposed algorithms are being tested with universal software radio peripheral (USRP) technology.