Multihopping in unlicensed spectrum
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
It is a common knowledge that certain radio frequency band is licensed for certain type of wireless/radio communication system. Most of the radio frequency bands are licensed and to get a license can cost money in some countries. However there are certain frequency bands which are unlicensed. Thus everybody who wants to use these frequency bands to transmit is allowed to do that. As frequency bands are limited resources and can cost, the operators are very keep to use these frequency bands. This is causing interference problems.
One possible scenario is that two operators decide to operate in the same area using the same frequency band. One previous study conducted by O. Queseth showed that the two networks belonging to the two operators cause a lot of interference to each other and thus suffer very much in capacity. It was further shown that the problem was more critical for the mobiles far away from own base stations but close to the competitive network’s base stations. Multi-hopping was suggested by me and my colleagues Thomas E. and Sujata M. as a solution to improve the capacities for the networks. Though the result showed a substantial improvement, we believed that it could be done better. The purpose of this thesis work has been to find a better working strategy for this system.
By modifying the routing and scheduling algorithms it has been found in this thesis that a routing algorithm which minimizes the total power consumed when sending packets and an adaptive S-TDMA as scheduling algorithm gives us very satisfying results.
It is also shown that by only changing the routing or the scheduling, we get either the same or even worse performance. The best strategy was to change both the routing algorithm and the scheduling. The profound strategy is working very well but it does not mean that there aren’t other pairs of routing and scheduling algorithms which could work better.
Place, publisher, year, edition, pages
2005. , 24 p.
TRITA-S3-RST, ISSN 1400-9137 ; 0514
Computer and Information Science
IdentifiersURN: urn:nbn:se:kth:diva-28100OAI: oai:DiVA.org:kth-28100DiVA: diva2:383957
Zander, Jens, Professor