Broadcasting of two generation cellular system control channel information over a three generation control channel to support roaming and handover to two generation cellular networks

• US 6,594,242 B1
• Filed: 01/14/1999
• Issued: 07/15/2003
• Est. Priority Date: 01/14/1999
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Kransmo, Jan L.
• Primary Examiner(s): LEGREE, TRACY MICHELLE
• Application Number:
  US09/231,844
• Time in Patent Office: 1,643 Days
• Field of Search: 370/831-834, 370/352, 370/342, 455/552, 455/553, 455/436-444, 455/450-452, 455/434, 455/517
• US Class Current: 370/331
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

A method, node and wireless communication terminal for providing handover and roaming from a 3G communication system to a 2G communication system. A dual-mode wireless terminal operating in a 3G communication system may obtain control channel information regarding a 2G communication system, and switch service as a function of the control channel information received. The method includes the step of providing control channel information for the 2G communication system over a downlink control channel of the 3G communication system to the wireless terminal. The node includes a means to communicate with the wireless communication terminal and a means providing control channel information of a second generation (2G) communication network over a downlink control channel at the 3G communication network. The wireless communication terminal includes a transceiver capable of communicating with a node of both a third generation (3G) wireless communication network and a second generation (2G) wireless communication network, and a control means coupled to the receiver for receiving and identifying control channel information indicative of the 2G communication network from a downlink control channel at the 3G communication network.

Claims

1. A method of supporting handover and roaming of a wireless terminal from a third generation (3G) communication system to a second generation (2G) communication system, comprising the steps of:

providing control channel information for said 2G communication system over a downlink control channel of the 3G communication system to the wireless terminal;

performing measurements on said 2G communication system bandwidth utilizing said control channel information;

determining a synchronization signal in said control channel information; and

synchronizing said 2G communication system with said 3G communication system utilizing said synchronization signal.

2. The method as specified in claim 1 further comprising the step of the wireless terminal monitoring the 3G communication system control channel.

3. The method as specified in claim 2 further comprising the step of switching service to the 2G communication system as a function of said control channel information received.

4. The method as specified in claim 1 wherein said control channel information is provided over a Broadcast Control Channel (BCCH).

5. The method as specified in claim 1 wherein said 2G communication system is selected from the group consisting of:

CDMA, TDMA, GSM, AMPS and D-AMPS and said 3G communication system is a WCDMA communication system.

6. The method as specified in claim 1, wherein the step of providing control channel information for said 2G communication system over a downlink control channel further comprises the step of receiving and identifying control channel information indicative of the 2G communication system for determining whether to synchronize with said 2G communication system.

7. The method as specified in claim 1, wherein said 2G communication system is a GSM communication system and said 3G communication system is a WCDMA system, said GSM communication system

generating a frequency burst to enable said dual mode wireless terminal to synchronize said terminal'"'"'s internal frequency with said GSM communication system and a synchronization burst for identifying a serving base station In said GSM network; and

said dual mode wireless terminal detecting said synchronization burst and synchronizing said terminal with said GSM communication system.

8. A wireless communication terminal, comprising:

a transceiver capable of communicating with a node of both a third generation (3G) wireless communication system and a second generation (2G) wireless communication system;

control means coupled to said transceiver for receiving and Identifying control channel information indicative of the 2G communication system from a downlink control channel at the 3G communication system;

means for performing measurements on said 2G carrier bandwidth utilizing said control channel information;

detector means for detecting a synchronization signal in said control channel information; and

synchronization means for synchronizing said wireless terminal with said 2G communication system.

9. The terminal as specified in claim 8 wherein said 2G communication system is selected from the group consisting of:

CDMA, TDMA, GSM, AMPS and D-AMPS and said 3G communication system is WCDMA.

10. The terminal of claim 8 wherein said terminal is a dual-mode wireless terminal.