A Comparative study on Handoff Algorithms for GSM and CDMA Cellular Networks

The GSM, CDMA cellular systems are most trendy 2G and 3G digital cellular telecommunications systems, which is widely used throughout the world. These systems have many advantages such as high security, higher quality of call transmission over the long distances, low transmitted power, and enhanced capacity with more efficient utilization of the frequency spectrum. With these advantages these cellular systems have attracted more subscribers with more attention in the field of mobile communications. One of the most attractive features of cellular system is handoff which is a continuation of an active call when the mobile is moving from one cell to another without disconnecting the call. Usually, continuous service is achieved by efficiently designed handoff algorithms. So, efficient handoff algorithms are necessary for enhancing the capacity and QoS of cellular system. In this paper, the handoff analysis for GSM, CDMA cellular networks are done under various propagation models. Various handoff algorithms of GSM are described and also a novel received signal strength (RSS) based GSM handoff algorithm with adaptive hysteresis is analyzed. CDMA Soft handoff algorithm is analyzed and effective soft handoff parameters are estimated for better performance. The Comparison of handoff algorithms is studied based on results

HANDOVER MANAGEABILITY AND PERFORMANCE MODELING IN MOBILE COMMUNICATION NETWORKS

In cellular Networks, a mobile station (MS’s) move from one cell region to another on seamless Communicationscheduling.. Handoff or Handover is an essential issue for the seamless communication. Several approaches havebeen proposed for handoff performance analysis in mobile communication systems. In Code-Division Multiple-Access (CDMA) systems with soft handoff, mobile stations (MS’s) within a soft-handoff region (SR) use multipleradio channels and receive their signals from multiple base stations (BS’s) simultaneously. Consequently, SR’sshould be investigated for handoff analysis in CDMA systems. In this paper, a model for soft handoff in CDMAnetworks is developed by initiating an overlap region between adjacent cells facilitating the derivation of handoffmanageability performance model. We employed an empirical modelling approach to support our analyticalfindings, measure and investigated the performance characteristics of typical communication network over a specificperiod from March to June, 2013 in an established cellular communication network operator in Nigeria. Theobserved data parameters were used as model predictors during the simulation phase. Simulation results revealedthat increased system capacity degrades the performance of the network due to congestion, dropping and callblocking, which the system is most likely to experience, but the rate of those factors could be minimized by properlyconsidering the handoff probabilities level. Comparing our results, we determined the effective and efficientperformance model and recommend it to network operators for an enhanced Quality of Service (QoS), which willpotentially improve the cost-value ratio for mobile users and thus confirmed that Soft Handoff (SH) performancemodel should be carefully implemented to minimize cellular communication system defects.Keywords: CDMA, QoS, optimization, Handoff Manageability, Congestion, Call Blocking and Call Dropping,

Performance Analysis of Multi-Service DS-CDMA Cellular Networks with Soft Handoff

DS-CDMA networks are fast evolving from voice only networks to multi-service networks. A key requirement for next generation networks is the ability to support a heterogeneous mix of services with varying traffic characteristics. Many papers assumed fixed capacities in their analysis which is applicable to FDMA and TDMA. Only recently have papers in the literature begun to analyze the effect of soft capacity and soft handoff on network performance. To the author\u27s best knowledge, there is none that analyzes the impact of soft handoff on multi-service DS-CDMA cellular networks. This thesis delineates the impact of soft handoff and user mobility on QoS parameters of multi-service DS-CDMA networks. The main contribution of this thesis is analytical model that includes soft handoff while supporting voice and video with user mobility taken into account. System performance parameters such as call blocking probability and call dropping probability are analytically determined using Markov Chain Analysis

On soft/hard handoff for packet data services in cellular CDMA mobiles systems

Benefits of macrodiversity operation for packet data services in third generation mobile systems are not obvious. Retransmission procedures to enhance link performance and higher downlink bandwidth requirements could question macrodiversity usage. This paper describes a simple methodology to compare soft and hard handoff performance in terms of transmission delay for packet data services. The handover procedures are based exclusively on power criteria and hysteresis margins.Peer ReviewedPostprint (published version

An Adaptive Soft Handover Scheme Using Fuzzy Load Balancing for WCDMA Systems

In cellular systems, user distribution variations can cause load imbalance between cells. Embedding a load balancing strategy within the handover scheme means that ensuing traffic congestion can be alleviated by dynamically reallocating load between neighbouring cells. An adaptive soft handover scheme for multimedia cellular communication systems is proposed in this paper, that considers both the cell load factors as well as the pilot channel signal-to-interference-and-noise-ratio (SINR) for soft handovers. By using fuzzy principles, the soft handover thresholds and time hysteresis are adapted dependent upon the loads of the neighbouring cells. Simulation results show that the new algorithm provides improved system performance in terms of a more evenly distributed load, lower blocking probabilities and higher throughput

Soft Handoff and Uplink Capacity in a Two-Tier CDMA System

This paper examines the effect of soft handoff on the uplink user capacity of a CDMA system consisting of a single macrocell in which a single hotspot microcell is embedded. The users of these two base stations operate over the same frequency band. In the soft handoff scenario studied here, both macrocell and microcell base stations serve each system user and the two received copies of a desired user's signal are summed using maximal ratio combining. Exact and approximate analytical methods are developed to compute uplink user capacity. Simulation results demonstrate a 20% increase in user capacity compared to hard handoff. In addition, simple, approximate methods are presented for estimating soft handoff capacity and are shown to be quite accurate.Comment: To appear in IEEE Transactions on Wireless Communication