Increased Capacity through Hierarchical Cellular Structures with Inter-Layer Reuse in an Enhanced GSM Radio Network ∗

Abstract. In today’s cellular networks it becomes harder to provide the resources for the increasing and fluctuating traffic demand exactly in the place and at the time where and when they are needed. Moreover, frequency planning for a hierarchical cellular network, especially to cover indoor areas and hot-spots is a complicated and expensive task. Therefore, we study the ability of hierarchical cellular structures with inter-layer reuse to increase the capacity of a GSM (Global System for Mobile Communications) radio network by applying Total Frequency Hopping (T-FH) and Adaptive Frequency Allocation (AFA) as a strategy to reuse the macro- and microcell resources without frequency planning in indoor picocells. The presented interference analysis indicates a considerable interference reduction gain by T-FH in conjunction with AFA, which can be used for carrying an additional indoor traffic of more than 300 Erlang/km2, i.e., increasing the spectral capacity by over 50%, namely 33 Erlang/km2 /MHz. From these results we draw a number of general conclusions for the design of hierarchical cellular structures in future mobile radio networks. For example, we may conclude that they require reuse strategies that not only adapt to the current local interference situation, but additionally distribute the remaining interference to as many resources as possible. For a hierarchical GSM network this requirement is fulfilled by the T-FH/AFA technique very well

Integration of unidirectional technologies into wireless back-haul architecture

This thesis was submitted for the degree of Docter of Philosophy and awarded by Brunel University.Back-haul infrastructures of today's wireless operators must support the triple-play services demanded by the market or regulatory bodies. To cope with increasing capacity demand, the EU FP7 project CARMEN has developed a cost-effective heterogeneous multi-radio wireless back-haul architecture, which may also leverage the native multicast capabilities of broadcast technologies such as DVB-T to off-load high-bandwidth broadcast content delivery. However, the integration of such unidirectional technologies into a packet-switched architecture requires careful considerations. The contribution of this thesis is the investigation, design and evaluation of protocols and mechanisms facilitating the integration of such unidirectional technologies into the wireless back-haul architecture so that they can be configured and utilized by the spectrum and capacity optimization modules. This integration mainly concerns the control plane and, in particular, the aspects related to resource and capability descriptions, neighborhood, link and Multi Protocol Label Switching (MPLS) Label-Switched Path (LSP) monitoring, unicast and multicast LSP signalling as well as topology forming and maintenance. During the course of this study we have analyzed the problem space, proposed solutions to the resulting research questions and evaluated our approach. Our results show that the now Unidirectional Technology (UDT)-aware architecture can readily consider Unidirectional Technologies (UDTs) to distribute, for example, broadcast content