Performance Study and comparison of Handover Mechanisms between WiMAX Mobile Multihop Relay (802.16j) and mobile WiMAX (802.16e) using NCTUns

Multihop wireless access networks are the subject of much interest at present. In the last few years they have moved from the domain of an interesting research topic to one having a significant impact on the commercial world. WiMAX (Worldwide Interoperability for Microwave Access) is introduced by the Institute of Electrical and Electronic Engineers with designated standards 802.16d-2004 and 802.16e-2005 (used in fixed wireless applications) and 802.16k-2006 (mobile wireless) to provide a worldwide interoperability for microwave access. For WiMAX networks, the IEEE has started in 2006 to work on 802.16j "Mobile Multihop Relay" (MMR). 802.16j offers a potential solution to some of the classic problems in deployment of radio access networks. Comprising low-cost relays associated with base stations (BSs), they can be used both to realize larger coverage areas for BSs and to increase capacity for congested areas. The basic idea behind MMR is to allow WiMAX base stations which do not have a backhaul connection to communicate with base stations that do. Multihop wireless systems have the potential to offer improved coverage and capacity over single-hop radio access systems. Standards development organizations are considering how to incorporate such techniques into new standards. One such initiative is the IEEE 802.16j standardization activity, adding relay capabilities to IEEE 802.16 systems. Relay-based systems typically comprise small form factor low-cost relays, which are associated with specific base stations. The relays can be used to extend the coverage area of a BS and/or increase the capacity of a wireless access system. Typically, it is envisaged that they could be used in the early stages of network rollout to provide coverage to a large area at lower cost than a BS only solution; they can also be used to provide increased capacity in more developed networks as well as coverage to coverage holes such as areas in the shadows of buildings. As the urban structures are getting heavily dominated by buildings day by day, network coverage in heaving areas blocked by buildings is a big challenge. The aim of 802.16j is to extend coverage area with improved capacity and low cost by the use of relay stations. In this thesis, the performance of standard handover mechanisms in MMR has been studied. NCTUns-6.0, which is an open source simulation tool that supports 802.16j standard, has been used in this thesis for the simulation. Only Hard Handover has been simulated on 802.16j scenario as NCTUns-6.0 only supports this handover method. Same simulation has been made on 802.16e scenario as well for the purpose of quantitative comparison. The performance parameters have been handover time, downlink throughput and transfer of packets. Keywords: Mobile Multhop Relay(MMR), WiMAX, Hard Handover, NCTUns, Base station(BS), Relay station(RS), OFDMA+4672309207