Handoff

Part 14

Handoff
1 2 3 Introduction . . . . . . . . . . . . . . . . . . 1.1 Reason for Reissue . . . . . . . . . . . . Background & Application . . . . . . . . . . . . . . . . . . . 14-3 14-3 14-3 14-4 14-4 14-4 14-6 14-6 14-8 14-9 14-9 14-10 14-11 14-11 14-11 14-12 14-12 14-12 14-14 14-14 14-14 14-16 14-16 14-19 14-20 14-23 14-24 14-25

Technical Description . . . . . . . . . . . . . 3.1Digital Hand-Off Criteria . . . . . . . . . 3.1.1 Mobile Assisted Hand-Off . . . . . . . . 3.1.2 Digital Call Supervision . . . . . . . . . 3.1.3 MS Presence Verification with Consistency Check . . . . . . . . . . . . . . . . . 3.1.4 Hand-Off Order . . . . . . . . . . . . . 3.2 Analog Hand-Off Criteria . . . . . . . . 3.2.1 Call Supervision . . . . . . . . . . . . 3.2.2 Locating . . . . . . . . . .. . . . . . 3.2.3 MS Presence Verification . . . . . . . . 3.2.4 Voice Channel Seizure . . . . . . . . . 3.2.5 Hand-Off Order . . . . . . . . . . . . . 3.3 Intracell Hand-Off . . . . . . . . . . . . 3.3.1 Digital Intracell Hand-Off . . . . . . . . 3.3.2 Analog Intracell Hand-Off . . . . . . . . 3.3.3 Intratransceiver and Intertransceiver Hand-Off . . . . . . . . . . . . . . . . 3.4 Intercell andIntralayer Hand-Off . . . . . 3.4.1 Digital Intercell Hand-Off . . . . . . . . 3.4.2 Analog Intercell Hand-Off . . . . . . . . 3.4.3 Overlay and Underlay Hand-Offs . . . . . 3.5 HCS Hand-Off . . . . . . . . . . . . . 3.5.1 Digital Interlayer Hand-Off by Neighbor Type . . . . . . . . . . . . . . . . . . 3.5.2 Analog Interlayer Hand-Off by Neighbor Type . . . . . . . . . . . . . . . . . . 3.6Interexchange Hand-Off . . . . . . . . . 3.7 Interhyperband Hand-Off . . . . . . . .

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1

Introduction
This document is a part of the Radio Network Design volume of the CMS 8800 RF Module. The information in this document is independent of Application System (AS )and can be used with any AS or system equipment. The document is intended for readers who have an understanding of Ericsson’s implementation of wireless telephone technology and an understanding of the basic principles of the analog and digital wireless standards, the Advanced Mobile Phone System (AMPS) and the Time Division Multiple Access ( TDMA) system, respectively.

1.1

Reason for ReissueThis document is reissued to incorporate technical changes to equation Equation 14-7 on page 14-15.

2

Background & Application
The hand-off feature allows an MS to change serving cells when the conditions warrant. A hand-off is initiated when the MS crosses a cell border or speech quality on an AVC or DTC is reduced to an unacceptable level. The system can initiate a hand-off any timeafter the voice path is established. If the called party is a mobile subscriber in the same exchange with call transfer active, hand-off for the calling party cannot occur before terminating. Hand-offs for DTC and AVC are categorized as interexchange, between two cooperating exchanges or as intra-exchange, within the same exchange. Both interexchange and intra-exchange can be categorized asinterhyperband if handing off between frequency bands. Interexchange is briefly described and more information can be found in the Cell Structure document of the Radio Network Design volume of this RF Module. Intra-exchange includes the following types of hand-offs: • • Intracell hand-off: within the serving cell Intercell hand-off: between serving cell and neighbor cells – – Intralayer hand-off: betweencells of the same layer Interlayer hand-off: between two different layers (HCS)

A hand-off attempt is executed according to a list of cells prioritized through an evaluation process called locating. The list may include the current serving cell, neighbor cells, overlay and underlay cells, and outer neighbor

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cells. See the Cell...