# US 8,787,315 B2 · Method and device for handing off between base stations

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- Number: US 8,787,315 B2
- Document ID: US8787315B2
- Status: Granted
- Kind: B2
- Application number: 13/257,869
- Filed: 2009-09-24
- Published: 2012-03-22
- Granted: 2014-07-22
- Earliest claimed: 2009-06-12
- Assignees: Zte Corporation
- Applicants: Boqiu Huang; Yu Liu; Yankun Zou; Qiang Wan; Wei Wang
- Inventors: Boqiu Huang; Yu Liu; Yankun Zou; Qiang Wan; Wei Wang
- Web page: https://patentgrep.com/patent/US8787315B2

## CPC

- H04W 36/0072: {of resource information of target access point}
- H04W 36/249: {according to timing information}
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

The present invention discloses a method and apparatus for handoff between base stations. A target base station bears its PILOT_INC information into a handoff request acknowledge message to inform a source base station when sending a handoff request acknowledge message to the source base station after receiving a handoff request from the source base station, thus, even if a UE requesting handoff reports PILOT_PN_PHASE under the target BS in a residual set, the source BS can determine PILOT_PN corresponding to the PILOT_PN_PHASE through the PILOT_INC information of the target base station, thereby completing cell handoff between the base stations successfully. The present invention is a supplement to the existing handoff between the base stations with configurations of the PILOT_INC information being different, and augments the success rate of handoff between the base stations of the UE, thereby improving the traffic service quality of a CDMA system.

## Claims

### Claim 1

A method for handoff between Code Division Multiple Access (CDMA) base stations comprising:
a target base station configuring a dedicated information unit bearing the PILOT_INC information in the handoff request ACK message, and bearing the PILOT_INC information into the dedicated information unit;
the target base station informing a source base station of Pilot pseudo noise sequence offset index increment (PILOT_INC) information of the target base station through a handoff request ACK message after receiving a handoff request message sent by the source base station, wherein the PILOT_INC of the source base station and the PILOT_INC of the target base station is different;
the source base station receiving the PILOT_INC information of the target base station, and according to the PILOT_INC information from the target base station to calculate pilot pseudo noise (PILOT_PN) corresponding to the pilot pseudo noise phase (PILOT_PN_PHASE) of the target base station reported by a user equipment that requests handoff between the base stations, thereby making the handoff between the base stations successful;
wherein an equation for calculating the pilot pseudo noise is:
PILOT_PN
=
⌊
PILOT_PN
⁢
_PHASE
+
32
×
PILOT_INC
64
×
PILOT_INC
⌋
×
PILOT_INC
,
where PILOT_PN means the pilot pseudo noise, PILOT_PN_PHASE means the pilot pseudo noise phase, and “└ ┘” means rounding down calculation.

### Claim 2 (depends on 1)

The method according to claim 1, before the step of the target base station informing the source base station of the PILOT_INC information through the handoff request ack message, the method further comprising:
the target base station bearing the PILOT_INC information into an existing information unit in the handoff request ack message.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the existing information unit in the handoff request ack message comprises a neighbor information unit in a neighbor list or extended neighbor list.

### Claim 4

An apparatus for handoff between Code Division Multiple Access (CDMA) base stations comprising:
a configuration unit configured to configure a dedicated information unit bearing the PILOT_INC information in the handoff request ACK message; and
a first bearing unit configured to bear the PILOT_INC information into the dedicated information unit;
a first receiving unit configured to receive a handoff request message sent by a source base station; and
an informing unit configured to inform the source base station of Pilot pseudo noise sequence offset index increment (PILOT_INC) information of a target base station; wherein the PILOT_INC of the source base station and the PILOT_INC of the target base station is different;
a second receiving unit configured to receive the PILOT_INC information of the target base station and a pilot pseudo noise phase (PILOT_PN_PHASE) of the target base station reported by a user equipment requesting handoff between the base stations; and
a calculating unit configured to calculate pilot pseudo noise (PILOT_PN) corresponding to the pilot pseudo noise phase using the PILOT_INC information of the target base station;
wherein the calculating unit is further configured to calculate the pilot pseudo noise by using the following formula:
PILOT_PN
=
⌊
PILOT_PN
⁢
_PHASE
+
32
×
PILOT_INC
64
×
PILOT_INC
⌋
×
PILOT_INC
,
where PILOT_PN means the pilot pseudo noise, PILOT_PN_PHASE means the pilot pseudo noise phase, and “└ ┘” means rounding down calculation.

### Claim 5 (depends on 4)

The apparatus according to claim 4, further comprising:
a second bearing unit configured to bear the PILOT_INC information into an existing information unit in the handoff request ack message.

### Claim 6 (depends on 5)

The apparatus according to claim 5, wherein the existing information unit in the handoff request ack message comprises a neighbor information unit in a neighbor list or extended neighbor list.