Relay-Assisted Spectrum and Infrastructure Sharing between Multiple Operators

Relay-assisted physical resource sharing has the potentia l to improve the spectral efficiency, enhance the coverage, and decrease the expenditures for opera- tors. By sharing the infrastructure (relay) and the spectru m, a new type of interference is created on the physical layer. Handling the interference demands novel physical layer techniques that are investigated in SAPHYRE project. In this paper, we de- scribe three relay sharing examples where the spectrum and the infrastructure (relay) are shared between multiple operators and introduce initial physical layer solutions. The first example considers a DS/CDMA system and studies the r esource allocation problem using a game theory approach. The results show that the proposed approach can achieve a significant gain in a heavily loaded system. The second one deals with a MIMO system and introduces a sub-optimal transmit strategy inspired by the inter- ference channel. Numerical results demonstrate that the proposed approach results in significant gains in terms of sum rate compared to an exclus ive assignment of the resources. The last case is inspired by wireless network coding and shows the hierar- chical exclusive code (HXC) design of a 2-source relay network.