Method for hand-over of terminal, network element, base station, and communication system
View Patent ↗The invention provides a method for hand-over of a terminal from a first base station to a second base station, radio network element, terminal, base station and a communication system. The method for hand-over of a terminal from a first base station to a second base station, wherein said first base station is EV-DO enabled in an access network and said second base station is not EV-DO enabled, said method comprising: transmitting an EV-DO pilot signal from said second base station to said terminal; sending a route update message including an EV-DO pilot strength from said terminal if said EV-DO pilot strength is above a predetermined threshold; calculating a CDMA pilot strength based on said EV-DO pilot strength; and performing the hand-over of said terminal to said second base station when CDMA pilot strength is above the hand-over threshold.
1. A method for hand-over of a terminal from a first base station to a second base station, wherein said first base station is EV-DO enabled in an access network and said second base station is not EV-DO enabled, said method comprising:
transmitting an EV-DO pilot signal from said second base station which is not EV-DO enabled to said terminal;
sending a route update message including an EV-DO pilot strength from said terminal if said EV-DO pilot strength is above a predetermined threshold;
calculating a CDMA pilot strength based on said EV-DO pilot strength; and
performing the hand-over of said terminal to said second base station when said CDMA pilot strength is above the hand-over threshold.
2. The method for hand-over of a terminal according to claim 1 , further comprising:
maintaining a pilots mapping table including at least a pilot code of CDMA and a pilot code of EV-DO for each border cell.
3. The method for hand-over of a terminal according to claim 1 , said pilot code comprises pseudo noise code.
4. The method for hand-over of a terminal according to claim 1 , wherein said step of calculating CDMA pilot strength based on said EV-DO pilot strength comprises:
calculating CDMA pilot strength based on said EV-DO pilot strength and a ratio of a pilot power to overall power at antenna port in CDMA cell.
5. The method for hand-over of a terminal according to claim 4 , wherein said ratio of a pilot power to overall power at antenna port in CDMA cell is defined as:
f
*
(
P
OH
+
P
T
)
P
OH
+
β
max
*
P
T
,
in which f is a ratio of a pilot power to a CDMA cell's maximum transmitter power, P OH is a power of overhead channel of the CDMA cell, P T is a total traffic power available for the CDMA cell, βmax is the maximum call load factor for the neighbor cells.
6. The method for hand-over of a terminal according to claim 1 , said step of transmitting an EV-DO pilot signal comprises:
generating an EV-DO pilot signal at said second base station.
7. The method for hand-over of a terminal according to claim 6 , said step of generating an EV-DO pilot signal comprises:
generating pseudo noise sequences of EV-DO for I and Q channel respectively based on an offset of pilot pseudo noise and transmitting time advance (Tx) provided by a controller of said second base station;
baseband filtering said PN sequences for I and Q channel respectively; and
Carrier modulating the PN baseband sequences for I and Q channel to obtain real signal from PN sequences for I and Q channel.
8. The method for hand-over of a terminal according to claim 7 , said step of generating an EV-DO pilot signal further comprises:
gating said sequences for passing 96 chips of 1024 chips within half slot and setting the remainder 0 for I and Q channel respectively.
9. The method for hand-over of a terminal according to claim 7 , said step of generating pseudo noise sequences uses two phase-shift registers for I and Q channels respectively.
10. The method for hand-over of a terminal according to claim , said step of generating pseudo noise sequences comprises:
judging the PN sequences for I and Q channel respectively based on system clock to output 96 chips of 1024 chips within half slot.
11. The method for hand-over of a terminal according to claim 7 , said step of generating pseudo noise sequences comprises:
multiplying said real signal with pilot gain after the step of carrier modulating.
12. A network element for controlling hand-over from a first base station to a second base station, wherein said first base station is EV-DO enabled in an access network and said second base station is not EV-DO enabled, comprising:
calculating unit configured to calculate a CDMA pilot strength based on an EV-DO pilot strength of said second base station which is not EV-DO enabled;
determining unit configured to determine whether said CDMA pilot strength is above a hand-over threshold; and
performing unit configured to perform the hand-over of a terminal from said first base station to said second base station when said CDMA pilot strength is above the hand-over threshold.
13. The network element according to claim 12 , further comprising:
maintaining unit configured to maintain a pilot mapping table including at least a pilot code of CDMA and a pilot code of EV-DO for each border cell.
14. The network element according to claim 13 , said pilot code comprises pseudo noise code.
15. The network element according to claim 12 , wherein said calculating unit calculates CDMA pilot strength based on said EV-DO pilot strength and a ratio of a pilot power to overall power at antenna port in CDMA cell.
16. The network element according to claim 15 , wherein said ratio of a pilot power to overall power at antenna port in CDMA cell is defined as:
f
*
(
P
OH
+
P
T
)
P
OH
+
β
max
*
P
T
,
in which f is a ratio of a pilot power to a CDMA cell's maximum transmitter power, P OH is a power of overhead channel of the CDMA cell, P T is a total traffic power available for the CDMA cell, βmax is the maximum call load factor for neighbor cells.
17. A hybrid terminal for use in a CDMA system and an EV-DO system, wherein said hybrid terminal is configured to receive an EV-DO pilot signal from said CDMA system via a base station which in not EV-DO enabled.
18. A device for generating a pilot signal, which is to be equipped with a non-EV-DO enabled base station in a CDMA system, wherein said device is configured to generating a EV-DO pilot signal.
19. The device for generating a pilot signal according to claim 18 , wherein said device comprises:
generating module configured to generate pseudo noise(PN) sequences of EV-DO for I and Q channel respectively based on an offset of pilot pseudo noise and transmitting time (Tx) advance provided by a controller of said second base station;
baseband filters individually configured to baseband filter the PN sequences for I or Q channel; and
Carrier modulating module configured to obtain real signal from PN sequences for I and Q channel.
20. The device for generating a pilot signal according to claim 19 , wherein said device further comprises:
gating modules configured to gate said sequences for passing 96 chips of 1024 chips within half slot and setting the remainder 0 for I and Q channel respectively.
21. The device for generating a pilot signal according to claim 19 , wherein said generating module comprises phase-shift registers for I and Q channel respectively.
22. The device for generating a pilot signal according to claim 19 , wherein said device further comprises:
multiplier configured to multiply the real signal provided by said QPSK modulating module with pilot gain.
23. The device for generating a pilot signal according to claim 19 , wherein said generating module comprises
output judging modules for I and Q channel respectively, configured to judge the PN sequences for I or Q based on system clock for outputting 96 chips of 1024 chips within half slot.
24. A device according to claim 18 implemented in a base station in a CDMA system, which is not EV-DO enabled.
25. A network element according to claim 12 implemented in a communication system comprising a hybrid terminal configured to receive an EV-DO pilot signal from a CDMA system and a base station in the CDMA system, which is not EV-DO.