Handover

About: Handover is a research topic. Over the lifetime, 24219 publications have been published within this topic receiving 296416 citations. The topic is also known as: handoff.

Handover procedures in a wireless communications system

Abstract: A wireless communications system having a radio access network (RAN). A wireless terminal is connected to a serving node in the RAN. The wireless terminal exchange messages with a serving node to support a handover to a target node in the RAN. The target node receives the hand over and provides to the wireless terminal the identity of one or more messages sent from the serving node to the target node that were not acknowledged by the wireless terminal. The wireless terminal provides information to the target node to prevent the retransmission of one or more stale messages following handover.

System and method for ranging for a fast handover in a mobile communication system

Abstract: A mobile communication system using an orthogonal frequency division multiplexing (OFDM)/orthogonal frequency division multiple access (OFDMA) scheme. The method for assigning ranging codes in the OFDM/OFDMA communication system includes classifying rangings between a base station and a mobile subscriber station (MSS) of the OFDM/OFDMA communication system into an initial ranging, a periodic ranging, a bandwidth request ranging, and a handover ranging. A first number of ranging codes used for the rangings are created and a second number of ranging codes selected from the first number of ranging codes are assigned as handover ranging codes used for the handover ranging.

An adaptive neuro-fuzzy based vertical handoff decision algorithm for wireless heterogeneous networks

Abstract: Currently, single wireless network technology can not satisfy all of the requirements of mobile users at anywhere and anytime. Due to such requirements as QoS provision, cost efficiency, mobility, and etc. integration of different wireless technologies is necessary and there is, in turn, an urgent demand to develop vertical handoff approaches that enable mobile terminals to seamlessly roam between wireless networks overlap with each other. In the quest for efficient handoff especially in the heterogeneous environment, various handoff decision making techniques have been proposed in the literature. In this paper, an adaptive fuzzy logic based vertical handoff decision making algorithm and an Adaptive Network Fuzzy Inference System (ANFIS) based vertical handoff decision making algorithm are developed for wireless heterogeneous networks which consist of GSM/GPRS, Wi-Fi, UMTS and WiMAX technologies. The parameters data rate, monetary cost and RSSI information are processed as inputs of the developed fuzzy based system. According to these parameters, an output value APCV which is utilized to chose the best candidate access point, is produced. Training data of ANFIS based vertical handoff decision making algorithm is obtained from the developed fuzzy based handoff algorithm and human expert. The results show that, compared to the typical fuzzy based algorithm, proposed ANFIS algorithm can provide enhanced outcomes for both user and network in terms of number of handoff, decision process time, and hardware implementation.

RAP-a novel medium access control protocol for wireless data networks

Abstract: A novel medium access control scheme, randomly addressed polling (RAP), is proposed and studied. RAP used in wireless networks allows that the base stations poll successfully only knowing the active mobile nodes via decentralized control without knowing the exact mobile nodes under coverage. Therefore, RAP can provide seemingless services for wireless (data) networks with good utilization of channel(s), transparent to multiple physical transmission, power efficiency for mobile nodes, and no handoff for data services (soft handoff for time-bounded services). In addition, the RAP protocol in infrastructured wireless (data) network architectures can be practically implemented with simple hardware and thus well suited for the medium access control protocol for wireless LANs and other personal communication systems,. >

Performance evaluation of connection rerouting schemes for ATM-based wireless networks

Abstract: Supporting mobility in asynchronous transfer mode (ATM)-based broad-band networks with wireless access links poses many technical challenges. One of the most important of these challenges is the need to reroute ongoing connections to/from mobile users as these users move among base stations. Connection rerouting schemes must exhibit low handoff latency, maintain efficient routes, and limit disruption to continuous media traffic while minimizing reroute updates to the network switches. In this paper we propose, describe an implementation for, and experimentally evaluate the performance of five different connection rerouting schemes. We show that one of these schemes, which operates in two phases, executes very fast reroutes (with a measured latency of 6.5 ms) in a real-time phase and, if necessary, reroutes again in a nonreal-time phase to maintain efficient routing. The scheme also results in negligible disruption to both audio (e.g., a 1-in-100 chance of a single packet loss at CD-quality audio rates of 128 kb/s) and low-bit-rate video (e.g., a 2-in-100 chance of a single packet loss for 1-Mb/s video) traffic during connection rerouting. Based on these results, we conclude that simple handoff schemes coupled with a connection management architecture are sufficient for supporting low-bit-rate continuous media applications over ATM-based wireless networks.