In this paper, we present an analytical model for the scheduled access mechanism of IEEE 802.15.6 based Wireless Body Area Network (WBAN) taking into account the impact of non-ideal transmission channel. We provide a thorough analysis and closed form expressions for the frame delay, reliability of data transfer, throughput, energy consumption, and Energy Efficiency (EE) of the sensor nodes with medium to high data rate applications. We validate our theoretical derivations through simulation results. The results show the variation in the performance indicators with respect to different system parameters, such as beacon period, data transmission rate, traffic loads, channel Signal-to-Noise Ratio (SNR), Allocation Intervals (AIs), and Payload Sizes (PSs). Our results indicate the tradeoff between average frame delay and EE with respect to selection of AIs and PSs. Thus, through this analysis we show how a network designer can prepare a look-up table for sensor nodes enabling them to select the optimum and minimum AIs and their associated PSs based on the channel SNR to achieve the maximum EE for a particular average frame delay and reliability constraint.

In this paper, we address the problem of predicting the time of occurrence of next activity, given the current activity and the context. The models that predict activity and time of occurrence rely on the basic idea that human beings perform sequence of activities at specific times regularly. In other words, the models are dependent on human behavior. However, human behavior changes over time. Also, due to demands and goals to be attained, there may be change in human behavior. Therefore, one of the essential requirements of the predictive models for the given task is autonomous adaptation with time and without undergoing any retraining. Considering the requirement of an adaptive model, we propose an evolving fuzzy rule-based predictive model that can autonomously adapt with changes in the human behavior. The performance of the model is evaluated using real-life data with evolving characteristics and satisfactory results are obtained.

An efficient Call Admission Control (CAC) scheme for IEEE 802.16e Mobile WiMAX that satisfies both bandwidth and delay guarantee to the admitted connections has been proposed in this paper. The proposed CAC scheme provides higher priority to Handoff connections, because it is more annoying to drop an ongoing connection than blocking a newly originated connection. Also UGS connections are given higher priority because UGS is the most common service used by the people for communication in everyday life. An analytical model is developed to evaluate the performance of the CAC scheme. The proposed CAC scheme is compared with two other existing CAC schemes proposed in literatures. Numerical results show that the proposed CAC scheme could be the better choice forAn efficient Call Admission Control (CAC) scheme for IEEE 802.16e Mobile WiMAX that satisfies both bandwidth and delay guarantAn efficient call admission control (CAC) scheme for IEEE 802.16e Mobile WiMAX that satisfies both bandwidth and delay guarantee to the admitted connections has been proposed in this paper. The proposed CAC scheme provides higher priority to handoff connections, because it is more annoying to drop an ongoing connection than blocking a newly originated connection. Also UGS connections are given higher priority because UGS is the most common service used by the people for communication in everyday life. An analytical model is developed to evaluate the performance of the CAC scheme. The proposed CAC scheme is compared with two other existing CAC schemes proposed in literatures. Numerical results show that the proposed CAC scheme could be the better choice for admission control in terms of blocking and dropping probabilities of the connections and bandwidth utilization of the system.

In this paper, we propose a new WLAN/GPRS integration architecture from the point of view of a GPRS operator's WLAN implementation. We introduce a new node, called serving GPRS access router (SGAR), and its associated protocol stack. SGAR acts as WLAN's access gateway to GPRS network so that a mobile terminal (MT) can use GPRS control signaling in WLAN networks in both tight and loose coupling modes. This avoids the requirements of extensible authentication protocol (EAP), implementing RADIUS servers and using expensive SS7 signaling link. NS-2 based simulation results show that the handoff delay in the proposed SGAR based integration technique is considerably less than that with RADIUS based authentication, under increasing packet sizes and/or increasing numbers of transmitting GPRS MTs. In fact, SGAR based tight coupling reduces the latency significantly, as shown in our experimentations.

The focus of this paper is to get the optimal hierarchical mobility management solution for next generation wireless IP-based networks. Hierarchical architectures prove advantageous in minimizing signaling overhead by limiting registration signaling locally. Our ultimate goal is to find the optimum hierarchy level, which should provide best performance in terms of networks parameters like signaling overhead, handoff latency and frequency of location updates. For this purpose an n-tiered architecture has been considered and optimality test on the number of tiers has been performed through analytical and ns-2 based simulation results. From the performance evaluation it is seen that time-bandwidth product is minimum for three-tiered network architecture leading as the optimal solution