Efficient Signaling of Spectral Resources in Spectrum Pooling Systems

Public mobile radio spectrum is a scarce resource while wide spectral ranges are only rarely used. Here, we consider a new strategy called Spectrum Pooling enabling public access to these new spectral ranges without sacrificing the transmission quality of the actual license owners. By temporarily leasing their spectrum during idle periods the license owners could tap new sources of revenue. We favor a modified wireless LAN as rental system. Especially OFDM based WLANs like IEEE802.11a and HIPERLAN/2 are suitable for an overlay system like spectrum pooling as they allow a very flexible frequency management on a carrier-by-carrier basis. The modifications of these standards comprise many areas of the physical and MAC layer. Idle frequency subbands can be detected by spectral power measurements conducted in each single participating mobile terminal. Hence, the volume of measurement data can become very high. Signaling this overhead in ordinary data frames would leave only few resources left for useful data and would be very error-prone. In this paper, we show that the signaling of spectral resources can be performed in the physical layer that has been harmonized for both considered standards. The basic idea is the superposition of emitted radio power for the signaling instead of creating new higher layer frames for the measured data. Furthermore, a robust method to broadcast information on spectral resources back to the mobile terminals is presented. Keywords— Radio resource management, spectrum pooling, OFDM, wireless LAN