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.

Call admission control for wireless networks

Abstract: Improved wireless telephone call admission methods for admitting new and/or handoff calls into a wireless telephone network having a plurality of communications channels. One such method, fractional guard channel call admission, effectively reserves a non-integral number of guard channels for handoff calls by rejecting new calls in accordance with a probability value that is dependent upon the current channel occupancy. Fractional guard channel call admission results in a significant reduction of new call blocking when a fixed constraint is placed on the handoff call blocking probability. Fractional guard channel call admission also provides improvements over the integral guard channel policy by minimizing the number of required channels when fixed constraints are placed on both the new call blocking probability and the handoff call blocking probability. In addition, methods are disclosed for computing optimized parameter settings for the fractional guard channel policy in the context of specified design objectives.

Seamless continuity of real-time video across UMTS and WLAN networks: challenges and performance evaluation

Abstract: This article addresses several challenges related to the evolution toward seamless interworking of wireless LAN and 3G cellular networks. The main objective is to evaluate the conditions and restrictions under which seamless continuity of video sessions across the two networks is feasible. For this purpose, we formulate a number of practical interworking scenarios, where UMTS subscribers with ongoing real-time video sessions hand over to WLAN, and we study the feasibility of seamless continuity by means of simulation. We particularly quantify the maximum number of UMTS subscribers that can be admitted to the WLAN, subject to maintaining the same level of UMTS QoS and respecting the WLAN policies. Our results indicate that the WLAN can support seamless continuity of video sessions for only a limited number of UMTS subscribers, which depends on the applied WLAN policy, access parameters, and QoS requirements. In addition to this study, we do address several other issues that are equally important to seamless session continuity, such as the QoS discrepancies across UMTS and WLAN, the vertical handover details, and various means of access control and differentiation between regular WLAN data users and UMTS subscribers. The framework for discussing these issues is created by considering a practical UMTS/WLAN interworking architecture.

Handbook of CDMA System Design, Engineering, and Optimization

Abstract: Preface. Foreward. 1. Introduction. References. 2. CDMA Overview. Concept. Attributes. Reference. 3. Spectrum Coordination. Spectrum Coordination. References. 4. Pilot Assignment. Introduction. Pilot Channel Model. Call Processing for a Mobile Station. PILOT_INC and Pilot Phase Offset Reuse. A Procedure for Phase Assignment. References. 5. Mobile Station Access and Paging. Description of Mobile Station Access Protocol. Average Persistence Delay for Access Request Attempt. Access Channel Capacity. Paging Channel Capacity. References. 6. Handoff. Hard Handoff. Soft and Softer Handoff. Inter-Carrier Handoffs. References. 7. Link Budgets. Derivation of the Reverse-Link Budget. Forward Link. References. 8. Capacity. Reverse-Link Capacity. Forward-Link Capacity. Reference. 9. Coverage. Reverse-Link Coverage Area. Forward-Link Coverage Area. A Derivation of Coverage Probability for Pilot Channel. Reference. 10. Traffic Engineering. Introduction. Analysis. Numerical Results. References. 11. Antennas. Introduction. Antenna Concepts. Antenna System with Interference and Cell Coverage. Diversity Antenna Systems. Antenna Isolation Guidelines for Collocated RF Stations. References. Appendix A: RF Design Process. Purpose. Process Overview. Preliminary Design Phase. Project Plan and Requirements Review. Data Preparation. Area Visits. Morphology Definition, Drive Test, and Calibration. Verify Input Parameters for Coverage Prediction. Capacity Planning. (Iterative) Engineering. Determine Search Rings. Preliminary Design Review. Final Design Phase. Candidate-Site Selection. Preliminary Evaluation of Candidate-Site Coverage. Drive Test of Candidate Sites. Drive-Test Data Analysis. Update Parameters Needed for Coverage Prediction. Capacity Planning/Traffic Studies. Final RF Candidate Site Selection and Sketch Preparation. Create Input to Cell Equipment Lists. PN Planning. Create Coverage Prediction Plots. Design Review. Appendix B: Outline of RF Optimization Procedures. Cluster Testing. System-Wide Optimization. Appendix C: RF Coverage Prediction with CE4. Overview of the CE4 Cellular Engineering Tool. Analysis Features Available for the Demo Version of CE4. System Requirements and Installation. Limitations of the Demo Version of CE4. Walk-Through of the CE4 Tool. Index.

Handoff control in an asynchronous CDMA system

Abstract: In a CDMA system in which the base stations are not each time aligned with one another, the handoff process accommodates the handoff by allowing for frame alignment. For example, frame alignment may be accomplished through the use of a selected set or may be remote unit aligned without reference to external sources. In addition, the neighbor list may included additional entries.