Concurrent Operation of Half- and Full-Duplex Terminals in Future Multi-Hop FDD Based Cellular Networks

Future OFDM-based cellular radio networks like IMT-Advanced systems are planned with both frequency division duplex and time division duplex in mind. Each of these duplex schemes has its benefits and drawbacks dependent on the scenario. In short-range communication and with small radio cells TDD is appropriate. For wide area cells FDD is preferred in general. If combined with multihop, i.e. the use of fixed relays, wide area cells can be built with a reduced number of base stations. Economic rationale also leads to the requirements to produce cheaper terminal equipment. Full duplex FDD terminals can transmit and receive simultaneously, but need high quality, expensive RF duplex-filters, in order to separate uplink and downlink channels. Half-duplex FDD terminals are lower in cost and therefore an interesting solution. This paper shows how half- duplex terminals should be operated to achieve the same performance as full-duplex terminals. The coordination of half- and full-duplex terminal operation by the base station is a challenge. This paper introduces the resource scheduling algorithm located in the MAC layer and discusses implications and performance results especially for multihop cellular networks.