Multi-hop cellular radio network integrating frequency and time duplexing
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The system concept developed by the Wireless World Initiative New Radio (WINNER) project, as part of the Information Society Technologies (IST) Sixth Framework Programme (FP6) of the European Union, as well as other future Orthogonal Frequency Division Multiple Access (OFDMA) based cellular mobile radio networks of the International Mobile Telecommunications (IMT)-Advanced system family, are planned with both Time Division Duplex (TDD) and Frequency Division Duplex (FDD), both as full-duplex and half-duplex transmission in mind. In general both schemes have their benefits and drawbacks. However, both schemes are more or less appropriate under consideration of the communication environment. In metropolitan area scenarios with relatively small radio cells TDD is appropriate. For wide area cells FDD is preferred in general. In future, data services will require ubiquitous mobile radio systems and demand support of an agreed Quality of Service (QoS) in terms of high data rate and low delay. A promising concept for future mobile radio communication systems is the ability to adapt to various deployment strategies by using different radio access technologies, so-called modes. The concept of modes provides customised solutions for specific environments and thus allows the adaptation to various scenarios by selecting the most adequate one. Fixed decode-andforward layer-2 relays are integral part of WINNER and will also be integral part of the next generation of mobile radio networks, namely IMT-Advanced systems. The application of layer-2 relays serves to optimise the cell capacity in a given area, cover otherwise shadowed areas and reduce the network deployment cost, substantially. This thesis introduces a concept for a layer-2 protocol supporting the integration of the two duplex schemes TDD and FDD, operating both full-duplex (fdx) and half-duplex (hdx) links, integrated as modes into one single Data Link Layer (DLL) protocol. Necessary functions for the realisation of coexistence and cooperation of modes are described in detail. The introduced concept furthermore supports the integration of decode-and-forward layer-2 relays including a detailed description of handover signalling in Relay-Enhanced Cells (RECs). By means of stochastic event-driven simulation of mode-handover in RECs, a proof-of-concept for the relay capable multi-mode DLL protocol is provided. Additionally, Radio Resource Management (RRM) aspects of an FDD-mode supporting both, fdx and hdx User Terminals (UTs), especially in REC scenarios are addressed and a performance analysis of the combined full- and half-duplex FDD mode is performed. To be able to support QoS even in RECs, a mode-specific static-priority scheduler is proposed serving for differentiating layer-2 connections belonging to a certain QoS class.