The growth in the good number of real-time and non-real-time applications has sparked a renewed interest in exploring resource allocation schemes that can be efficient and fair to all the applications in overloaded scenarios. In this paper, the performance of six scheduling algorithms for Long Term Evolution (LTE) downlink networks were analyzed and compared. These algorithms are Proportional Fair (PF), Exponential/Proportional Fair (EXP/PF), Maximum Largest Weighted Delay First (MLWDF), Frame Level Scheduler (FLS), Exponential (EXP) rule and Logarithmic (LOG) rule.  The performances of these algorithms were evaluated using an open source simulator (LTE simulator) and compared based on network parameters which include: throughput, delay, Packet Loss Ratio (PLR), and fairness. This work aims at giving insight on the gains made on radio resource scheduling for LTE network and to x-ray the issues that require improvement in order to provide better performance to the users. The results of this work show that FLS algorithm outperforms other algorithms in terms of delay, PLR, throughput, and fairness for VoIP and video flow. It was also observed that for Best Effort (BE) flows, FLS outperforms other algorithms in terms of delay and PLR but performed least in terms of throughput and fairness. http://dx.doi.org/10.4314/njt.v36i1.21

The need to increase spectral efficiency has led to the design of multiple antenna systems for both transmit and receive sides otherwise known as MIMO. Channel modeling forms an integral part of this design. Therefore it is very important to investigate and understand existing MIMO channel models. This paper provides a detailed review of existing MIMO channel models, their characteristics, tradeoffs and challenges. As with most models in the scientific and technical fields, open issues in MIMO channel modeling have also been enumerated.

Owing to the emerging realities in the Information and Communication Technology (ICT) industry, where data traffic is growing much faster than traditional voice traffic, there is now a global growing desire to migrate to digital form of communication. The trend is focused in transporting voice over data networks rather than the traditional data over voice networks. Voice traffic carried over a system originally designed for data creates technical challenges. This is primarily due to limitations that have resulted from the nature of the Internet and its bandwidth, transmission impairments and voice compression technology, which degrade voice quality. In this paper, the design of a hybrid architecture of an efficient packet scheduler for optimizing the QoS of VoIP networks have been presented. The design addresses the transmission impairment factors of delay (or latency), jitter (or delay variation) and packet loss. Mechanisms for: accommodating the demands of the expected rapid increase in the volume of voice traffic as PSTN progressively migrates to VoIP; according due precedence to the delay-sensitive voice and business/mission critical data (B/MCD) traffic flows; ensuring fair resource sharing among all traffic flows (realtime and non real-time) and adaptively maintaining optimal voice quality without over provisioning the users, have been incorporated. In the analysis, the algorithm defining the different levels of services was developed and explained. The interaction and integration of the designed functional pieces were used to develop a structured signal flowchart. The work therefore provides a theoretical framework that guarantees a graceful tradeoff between priority and fairness to all traffics flows running on the network.

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The increase in GSM mobile station (MS) density, without a corresponding increase in radio channel resource capacity, reduces the quality of service (QoS) standard provided to users. Attempts to improve the QoS standard usually leads to the creation of new base stations (BS) with the consequent reduction in the existing cell sizes. Although, the available network capacity is increased, this happens at the expense of increased numbers of call handoversSuch increase is usually accommodated by resource reservation. How well the reservation is made greatly influences the GSM network quality of service (QoS) and the general BS resource utilization. This work presents a radio channel resource reservation technique for GSM handover calls. A typical GSM network architecture was modeled using an integrated modeling technique in a MATLAB block oriented simulation environment. The analytical part of the model was developed using the Markov chain principle and validated using the existing popular Lee's queuing model. The relationships between the handover call blocking probability, fresh call blocking probability, the number of resources to be reserved and traffic intensity were established. Simulation results were analyzed and a method of determining the optimum number of resources that can be reserved for handover calls for a given BS resource capacity was presented.