Spectral Efficiency and User Diversity Gains Through Cooperative Fixed Relays

Cooperative diversity through mobile terminals is faced with a number of deployment challenges such as security (as terminals have to detect partner´s signals), incentive and coercion packages (as users have to be motivated to use their terminals to assist others), and huge capital investment (as terminals have to be modified to make them ready for cooperation). This paper discusses fixed relay-enabled user cooperation that are being considered in the WINNER project for deploying beyond 3G wireless communication networks. The schemes operate by engaging two users in cooperation without their knowledge. The schemes which can be viewed as an add-on to network facility have significant impact on the costs, security and end-to-end (E2E) performance of two-hop wireless networks. In addition, the proposed schemes can be used in a number of networks since current terminals do not require any modifications.