[Paper Review] Handover between Macrocell and Femtocell for UMTS based Networks

Mostafa Zaman Chowdhury, Won Ryu+2 more|arXiv (Cornell University)|Oct 5, 2018

Advanced MIMO Systems Optimization4 references88 citations

TL;DR

The paper proposes handover optimization for UMTS macrocell–femtocell networks, introducing architectures, signal-flow changes, and an unnecessary handoff minimization scheme, with simulation validation.

ABSTRACT

The femtocell networks that use home base station and existing xDSL or other cable line as backhaul connectivity can fulfill the upcoming demand of high data rate for wireless communication system as well as can extend the coverage area. Hence the modified handover procedure for existing networks is needed to support the macrocell/femtocell integrated network. Some modifications of existing network and protocol architecture for the integration of femtocell networks with the existing UMTS based macrocell networks are essential. These modifications change the signal flow for handover procedures due to different 2-tier cell (macrocell and femtocell) environment. The measurement of signal-to-interference ratio parameter should be considered for handover between macrocell and femtocell. A frequent and unnecessary handover is another problem for hierarchical network environment that must be optimized to improve the performance of macrocell/femtocell integrated network. In this paper, firstly we propose the concentrator based and without concentrator based femtocell network architecture. Then we present the signal flow with appropriate parameters for the handover between 3GPP UMTS based macrocell and femtocell networks. A scheme for unnecessary handoff minimization is also presented in this paper. We simulate the proposed handover optimization scheme to validate the performance.

Motivation & Objective

• Address growing demand for high data rates and extended coverage via femtocells in UMTS networks.
• Integrate femtocell backhaul with UMTS macrocell networks through architecture modifications.
• Reconfigure handover procedures to suit a two-tier macrocell/femtocell environment.
• Reduce unnecessary/missed handovers to improve overall network performance.

Proposed method

• Proposes concentrator-based and non-concentrator-based femtocell network architectures.
• Describes the signal flow for handover between 3GPP UMTS macrocell and femtocell networks.
• Identifies and incorporates signal-to-interference ratio (SIR) as a key handover parameter.
• Presents a scheme to minimize unnecessary handovers in the hierarchical network.
• Provides simulation-based validation of the proposed handover optimization scheme.

Experimental results

Research questions

• RQ1 How should handover procedures be modified to support a two-tier macrocell–femtocell UMTS network?
• RQ2 What signal-flow parameters, particularly SIR, influence handover decisions in this architecture?
• RQ3 Can an optimization scheme effectively reduce unnecessary handovers without degrading performance?
• RQ4 What architectural choices (concentrator-based vs. non-concentrator-based) impact handover performance?
• RQ5 Does simulation validate the effectiveness of the proposed handover scheme in improving network performance?

Key findings

• Modified handover procedures change the signal flow in a macrocell–femtocell environment.
• SIR-related measurements are essential for reliable macrocell-to-femtocell handovers.
• A scheme to minimize unnecessary handovers is proposed to mitigate excessive handoff in hierarchical networks.
• Concentrator-based and non-concentrator architectures are analyzed for their impact on handover performance.
• Simulation results validate the effectiveness of the proposed handover optimization approach.