http://hdl.handle.net/10500/2916 Thu, 20 Jun 2013 02:37:41 GMT 2013-06-20T02:37:41Z http://hdl.handle.net/10500/5552 The WiMAX PHY Layer Odhiambo, Marcel O.; Rayolla, Amimo P.O. Wed, 07 Mar 2012 00:00:00 GMT http://hdl.handle.net/10500/5552 2012-03-07T00:00:00Z http://hdl.handle.net/10500/3669 Towards a converged network : video streaming over WiMAX vs. HSDPA in the rural environment Odhiambo, M.O.; Amimo-Rayolla, P. O.; Kurien, A.M. As the telecommunications industry evolves towards a converged IP-Core network the role of cellular/wireless broadband technologies in achieving Long Term Evolution (LTE) must be greatly evaluated. This would in effect provide lessons for improvement and blueprints for final adoption in NGN (Next Generation Networks). The emergence of BWA (broadband wireless access) as a reliable player, in some cases a substitute for fibre/ADSL, maybe attributed to poor or non-existent copper/fibre, largely inefficient telecommunications management and/or ineffective telecommunications policies in mostly underserviced areas. In this paper, video streaming over existing 3G high-speed packet networks is evaluated against WiMAX as alternatives to fibre/ADSL. Simulation results show WiMAX was found to be a viable and better alternative barring capital expenditure (CAPEX) and operational expenditure (OPEX) considerations. HSDPA was found to achieve rates per user equipment (UE) that meet QoS needs for codec streaming Q-levels of 16 and 64 kbps. The 16 kbps codec rarely requires extensive preroll buffer requirements. However, WiMAX was found to perform better by at least three times for throughput and capacity. Wed, 23 Sep 2009 00:00:00 GMT http://hdl.handle.net/10500/3669 2009-09-23T00:00:00Z http://hdl.handle.net/10500/3655 Enhancing video streaming in 802.11wireless mesh networks using two-layer mechanism solution Moleme, N. H.; Odhiambo, M.O.; Kurien, A.M. Multihop wireless mesh networks have emerged as the next generation in wireless network technology. This is due to the advantages provided by the mesh network technology. WMNs provides ease of installation, cost effective deployments, high level of scalability, wide coverage area and capacity, network flexibility and self-configuration capabilities. However, despite these advantages, many research challenges still remain in WMNs. One such challenge is the support of real time applications such as video streaming. This paper proposes a two-layer mechanism for the transportation of real-time video. In this mechanism, rate adaptation is implemented in the data link layer for channel error control, link stability and reliability. In addition, the network layer routing protocol is optimized for congestion control and optimal route selection by using congestion information from the data link layer and link quality metric from the network layer. Simulation results show that the proposed mechanism improves the network performance in terms of throughput, delay and jitter in multihop wireless mesh networks when UDP is used as the transport protocol. This paper was presented at the, IEEE AFRICON Conference, 23-25 Sept. 2009, Nairobi, Kenya, pp. 1-6. Wed, 23 Sep 2009 00:00:00 GMT http://hdl.handle.net/10500/3655 2009-09-23T00:00:00Z http://hdl.handle.net/10500/3654 TESPAR Coded Speech Quality Evaluation (TCSQE) : A New Algorithm for Objective Measurement of Speech Quality in Cellular Networks Adar, Philip O.; Odhiambo, Marcel O. Speech transmission quality measurement in cellular networks is a major indicator of performance for end-to-end quality of service standards. Many approaches have been proposed in the previous studies, but the results correlation with subjective experiments still need further optimization, especially for quality determination using languages with unique phonetic structures i.e. clicking sounds. Moreover, the evaluation test data is always a key element in order to obtain representative and consistent results. In this paper, we introduce TESPAR coding technique for the design of a new algorithm for speech (voice) quality measurement in cellular/wireless telecommunication networks. Our experiments show that the results from this algorithm correlates well with subjective experiments using a variety of speech samples. The proposed algorithm is also computationally efficient than the existing methods and is suitable for quality measurement of longer speech signals than the current 8 seconds speech test data mostly in use today. Wed, 23 Sep 2009 00:00:00 GMT http://hdl.handle.net/10500/3654 2009-09-23T00:00:00Z