Link Quality Measurement and Handoff Initiation

  • Gordon L. Stüber


Cellular systems must have the ability to maintain a call while a mobile station (MS) moves throughout a cellular service area. This is accomplished by performing a handoff to an alternate base station (BS) whenever the link quality with the serving BS becomes unacceptable. A variety of parameters such as bit error rate (BER) [54], carrier-to-interference ratio (C/I) [103], distance [209], [85], traffic load, signal strength [209], [130], [132], [225], [41], [319], and various combinations of these fundamental schemes have been suggested for evaluating the link quality and deciding when a handoff should be performed. Of these, temporal averaging signal strength based handoff algorithms that measure the received carrier plus interference power (C+I) have received the most attention due to their simplicity and good performance in macrocellular systems. As a reflection of this trend, much of this chapter will be devoted to these types of handoff algorithms. However, spectrally efficient cellular systems are interference limited and a large C+I does not necessary imply a large C/I. Since radio link quality is more closely related to C/I than to C+I, it is apparent that C/I based handoff algorithms are highly desirable for microcellular systems with their characteristically erratic propagation environments. Unfortunately, C/I measurements can be quite difficult to obtain in practice [180], [348] and, hence, practical resource allocation algorithms often resort to received (C+I) measurements as a quality measure. Nevertheless, some discussion of C/I measurement techniques will be presented in this chapter.


Mobile Station Additive White Gaussian Noise Receive Signal Strength Velocity Estimate Velocity Estimator 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer Science+Business Media New York 1996

Authors and Affiliations

  • Gordon L. Stüber
    • 1
  1. 1.Georgia Institute of TechnologyUSA

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