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Since the advent of 1G through 5G networks, telecommunication industry has gone through phenomenal transformation in the way we communicate, we work, and we socialize. In dense or ultra-dense mobile communication networks, the users are very frequently handed over to other cells making seamless mobility a challenging and complex problem. Therefore, robust connectivity in such networks becomes a very critical issue. In this paper, we present a data-driven handover optimization approach aiming to mitigate the mobility problems including handover delay, early handover, wrong selection of target cell and frequent handover. The proposal is based on collecting the information from the network and developing a model to determine the relationship between the features drawn from the collected dataset and key performance indicator (KPI) expressed as the weighted average of mobility problem ratios. Handover design parameters- time to trigger and handover margin are optimized to improve KPI. The KPI estimation drawn on time to trigger and hysteresis margin design parameters is estimated through neural network multilayer perception method. It is established through simulation results that the proposed approach yields significantly improved handover performance mitigating mobility problem in ultra-dense cellular networks to notable extent. [ABSTRACT FROM AUTHOR]

Device-to-Device (D2D) communication is seen as a promising technology to offload exponentially increasing cellular data traffic. This also enhances spectral and energy efficiency of the cellular network. However, co-channel interference restricts the potential gain of Underlay-D2D (U-D2D) communication technology. In this paper, we propose a novel resource allocation scheme coupled with distributed power control strategy to reduce co-channel interference and improve overall system sum rate. Resource allocation is based on overlapping coalition formation game model. Overlapping coalitions allow a single D2D pair to utilize multiple resource blocks, which provides enhanced transmission bandwidth per user. But, this improved bandwidth is achieved at the cost of increased co-channel interference. The proposed scheme mitigates this problem by distributed control of D2D transmit power in accordance with the interference sensed on each resource block allocated for that particular D2D pair. It is shown through numerical results that there is a significant improvement in overall U-D2D system performance in terms of system sum rate and D2D transmission ratio in comparison with other existing techniques. [ABSTRACT FROM AUTHOR]

The capacity and coverage area are the two most important design considerations for the planning and optimisation of cellular networks. In this paper, we report on the field measurements of received signal strength (RSS) and available data transfer rate (DTR) at user end in a fixed WiMAX network operating at 2.62 GHz. The coverage area of the network under study covers both rural and urban sectors. Comprehensive measurements of RSS and available DTR are recorded for different settings of the base station antenna tilt and the height of customer premise equipment (CPE) antenna installed at the user premise. It is a directional antenna oriented towards the base station facilitating line of sight communication. It is interesting to observe that base station antenna down-tilt of 2° results in almost 100% fulfilment of the coverage and capacity requirements in rural sector of the network. Up-tilt of 1°, yields 97% fulfilment of the requirements in the entire cell area. These settings of the base station antenna tilt offers encouraging results for the optimisation of both capacity and coverage area and establishes that antenna tilt is an effective optimisation tool to achieve better utilisation of the network resources with enhanced quality of service. [ABSTRACT FROM AUTHOR]

Mobility management is the most important feature of a wireless cellular communication system. Continuation of an active call is one of the most important quality measurements in the cellular systems. Handover makes it possible for a user to travel between various networks or cells while having a seamless connection. This paper shows that, performance of cellular network can be increased with proposed adaptive soft handoff algorithm, which dynamically calculates the Soft handover margin based on the received signal strength and distance. Performance is evaluated in terms of the performance metrics active set update rate, active set size, soft handover region and probability of outage. Simulation results show that soft handover algorithm gives better performance with adaptive soft handoff margin compared to that of fixed soft handover margin in varied propagation conditions. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new empirical formula for handover rate as a function of base stations separation, standard deviation of shadow fading, path loss exponent, averaging distance, and correlation distance. The handover initiation algorithm is based on averaged signal strength measurements using relative signal strength with hysteresis margin approach. We generate the data through computer simulations for the average number of handovers referred to as handover rate, for the practical range of path loss exponent and standard deviation of shadow fading. The proposed formula provides for a practical design tool to optimize the handover initiation performance under varied propagation environments. [ABSTRACT FROM AUTHOR]