Mobility Management for LTE-Advanced Relay Systems Research Paper

Mobility Management for LTE-Advanced Relay Systems - Research Paper Example These different technologies can cooperate together In order to improve the user’s quality of service and granting mobile users the ability of roaming across different wireless networks in a seamless manner. However, the different characteristics of each wireless technology with regards to QoS brought many challenges for provisioning the continuous services (e.g. audio/video streaming) in a seamless way. In such a heterogeneous environment, to support mobile user’s requirements, a mobility management mechanism is a key issue. Index Terms— Heterogeneous network, LTE-Advanced, Relay System, Vertical Handoff I. INTRODUCTION With the increase in demand and rapid development of wireless communication quality over the past 3 decades, the initial 1G has run into 4G with a high data rate and better mobility support. The 4G technique-International Mobile Telecommunications-Advanced (IMT-Advanced) systems include new capabilities that go significantly beyond those of the I MT-2000. Key requirements of the IMT Advanced systems, for instance, include improved mobility support and cell edge performance, increased spectral bandwidth and efficiency, reduced handover interruption time and reduced User plane latency and Control [1]. Considered as the main trend in future wireless communications, 3GPP LTE-Advanced has advanced features, for instance coordinated multipoint processing, carrier aggregation. It also considered as one of the top candidates towards achieving the IMT Advanced requirements. In 3GPP, high speed train scenario is agreed as the main scenario in Rel11 study item, mobile relay for E-UTRA. Here, when train rushes at a high speed the channel characteristics change and result in Doppler spread. Also the vehicles are vehicles are more crowded than other areas and therefore passengers are more likely to use high data rate services, for instance, browsing, playing games and watching videos so as to pass time [2]. The high data rate transmission requires strong signal strengths and high throughput, plus better mobility management, so mobile relay station for large vehicles are proposed for Broadband Wireless Access (BWA) system. A relay system may be mobile, which means it is a dedicated network node equipped on the vehicles to provide a fixed access link to those travelling on the vehicles. It is very suitable to solve the capacity gain of the high speed vehicles if it is well deployed. In a conventional cellular network, user equipment (UE) is connected directly to a Base Station (BS), and when a user moves away from the cell center, he/she will get less bandwidth which means lower data rates. However relaying technique has been introduced in 3GPP release 10 & 11 to allow establishing an indirect two-hop link between UE and BS through a Relay Node (RN). Relay nodes can also be used to spread out the cell coverage and increase the coverage outside main area (e.g. at cell edge). The two major challenges addressed in this c ontext are maintaining the throughput and ensure a seamless mobility and service continuity to all UEs. Hence, the objective of this paper is to develop, implement, and evaluate intelligent algorithms for next generation wireless communications systems with focus on throughput and service continuity. Specifically, the paper mainly addresses to the following aspects: Relaying in heterogeneous network, resources and mobility management. The rest of the paper is arranged as follows. Firstly, the overview of fixed and mobile relay system is given is Section II. In Section III, the paper presents a Handoff Analysis. Section IV presents a system level simulation and results. The paper concludes with section V. II. FIXED AND MOBILE RELAY SYSTEMS OVERVIEW A. Background