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Abstract. This work introduces a new analytical method for performance evaluation of wireless packet-oriented networks. Unlike traditional call admission control procedures commonly used for performance evaluation of wireless networks, this paper deals with the problem of coupling connection and packet level QoS characteristics by analysis. At connection level we use the Blocked-Calls-Cleared (BCC) model, whereas at packet level we use the Blocked-Call-Interfered (BCI) model which has no immediate feedback from packet level to connection level about lost data. At connection level we use the convolution algorithm which defines the feasible state space at packet level. At packet level we take into consideration wireless interference (soft blocking). The traffic is modeled as multi-rate Binomial-Poisson-Pascal (BPP-) traffic at connection level and on-off traffic at packet level. We obtain individual performance measures for each service, both at connection level and at packet level. By case studies we investigate the trade-off between the two levels to meet Grade of Service (GoS) requirements for cellular networks with WCDMA radio interface. Keywords: Two-level analysis, WCDMA, multi-service wireless network, connection level, packet level, soft blocking, teletraffic, Blocked-Calls-Cleared, Blocked-Calls-Held, Blocked-Calls-Interfered models. 1

There is considerable interest at this time in developing small satellites for quick-turnaround missions to investigate near-earth phenomena from space. The aim of the thesis is to investigate issues related to the migration from current Pre-planned Multiple Access operation mode to the next generation on-demand mode focusing on spacecraft in near earth orbits. In this thesis, an evolutionary on-demand mode network architecture is proposed. One of the most important design issues is the development of medium access control (MAC) schemes. For this new scenario, to meet the objective of the bandwidth-efficient support while guaranteed specific QoS requirements, a detailed investigation of the suitability of the MAC schemes is performed. Performance measures of interest include end-to-end delay, successful throughput and channel efficiency. The general protocol investigation framework is first given. Reservation-based Demand TDMA protocol is proposed for the dynamicLEO scenario. Performance evaluations are performed by means of simulation. We compare the system’s performance under Reservation-based demand-assigned multiple-access channel allocation schemes with that obtained under fixed-assigned scheme. Simulation results demonstrate that on-demand mode is a suitable strategy for next-generation NASA space mission with unpredictable traffic pattern, and can offer certain performance advantages. ON-DEMAND MULTIPLE ACCESS

We develop scheduling strategies for carrying multimedia traffic over a polled multiple access wireless network with fading. We consider a slotted system with three classes of traffic (voice, streaming media and file transfers). A Markov model is used for the fading and also for modeling voice packet arrivals and streaming arrivals. The performance objectives are a loss probability for voice, mean network delay for streaming media, and time average throughput for file transfers. A central scheduler (e.g., the access point in a single cell IEEE 802.11 wireless local area network (WLAN)) is assumed to be able to keep track of all the available state information and make the scheduling decision in each slot (e.g., as would be the case for PCF mode operation of the IEEE 802.11 WLAN). The problem is modeled as a constrained Markov decision problem. By using constraint relaxations (a linear relaxation and Whittle type relaxations) an index based policy is obtained. For the file transfers the decision problem turns out to be one with partial state in-formation. Numerical comparisons are provided with the performance obtained from some simple policies.

Wireless Multimedia Sensor Networks (WMSNs) is simply a wireless sensor network supporting multimedia traffic by deployment of data sensors and multimedia sensors as the nodes. The requirements of the WMSN is much different and specific as compared to other genera wireless networks, hence requires more specific protocols designed for each layers. These layers need to support the issues that multimedia traffic brings to the sensor networks, e.g. QoS, energy, MAC layer, bandwidth, etc. However it doesn’t support the cause that these protocols are being treated as independent identities, as WMSN requires a cross-layer optimization of these protocols for proper functioning. With the assumption that most of the multimedia traffic consists of real-time video sensing and transmission, several solutions have been released, proposed and still are in research.