Dispatch mode in code division multiple access systems

• US 6,292,671 B1
• Filed: 08/03/1999
• Issued: 09/18/2001
• Est. Priority Date: 08/03/1999
• Status: Expired due to Term

• Current Assignee: Sprint Spectrum LLC (Deutsche Telekom AG)
• Original Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Inventors: Mansour, Nagi A.
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): Milord, Marceau
• Application Number:
  US09/366,609
• Time in Patent Office: 777 Days
• Field of Search: 455/518, 455/519, 455/456, 455/445, 455/517, 455/524, 455/520, 370/342, 370/335, 370/260, 370/261, 370/349, 370/338, 370/310, 370/320, 370/441, 370/479
• US Class Current: 455/518
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

A method of providing dispatch mode calling in a code division multiple access (CDMA) wireless network (10). The method includes the steps of defining at least one dispatch mode talk-group, receiving a dispatch mode call request from an originating mobile phone (48) in the talk-group, determining location information for destination mobile phones (50, 52, 54, 56) in the talk-group, and encoding and sending the voice packets to the destination phones, along with information to enable the destination phones to decipher the encoded voice packets.

Claims

1. A method of providing dispatch mode calling in a CDMA wireless telecommunications network including a plurality of base stations each providing wireless service in a telecommunications cell, the method comprising the steps of:

defining at least one talk-group consisting of a plurality of mobile phones in the CDMA network operated by users who wish to communicate with each other in a dispatch mode;

receiving a dispatch mode call request from an originating mobile phone in the talk-group operated by a user wishing to initiate communication with destination mobile phones in the talk-group operated by other users;

determining location information for the destination mobile phones in the talk-group;

receiving voice packets from the originating mobile phone;

encoding the voice packets;

providing information to the destination mobile phones that enables the destination mobile phones to decipher the encoded voice packets; and

transmitting the encoded voice packets to cells in the CDMA network in which the destination mobile phones are located so that the destination mobile phones can decipher the encoded voice packets to communicate with the user of the originating mobile phone, the transmitting step further including the steps of;

determining in which cell each of the destination mobile phones are located;

if all of the destination mobile phones are located in one cell, routing the encoded voice packets to a base station corresponding to the cell;

if the destination mobile phones are located in a plurality of cells serviced by a single mobile switching center, replicating the encoded voice packets and routing the voice packets to all base stations serviced by the single mobile switching center corresponding to the cells in which the destination mobile phones are located; and

if the destination mobile phones are located in a plurality of cells serviced by different mobile switching centers, replicating the encoded voice packets and routing the voice packets to all base stations corresponding to the cells in which the destination mobile phones are located via the mobile switching centers and a public switched telephone network coupled with the mobile switching centers.

2. The method as set forth in claim 1, wherein the CDMA wireless network transmits voice traffic to the mobile phones over forward traffic channels, the method further including the steps of assigning a firstWalsh code to a forward traffic channel for the originating mobile phone and assigning a second Walsh code to a forward traffic channel for all of the destination mobile phones.

3. The method as set forth in claim 1, wherein the user of the originating mobile phone requests a dispatch mode call by striking a dedicated key on the originating mobile phone.

4. The method as set forth in claim 1, wherein each of the mobile phones are operable to communicate both in a dispatch mode and in a conventional non-dispatch mode.

5. A wireless network using code division multiple access techniques comprising:

a plurality of first base stations each providing wireless communication to a plurality of mobile phones positioned in a first telecommunications cell;

a first base station controller coupled with the first base stations for controlling operation thereof;

a first mobile switching center coupled with the first base station controller for managing and establishing calls destined for and originating from the mobile phones in the first telecommunications cell;

a plurality of second base stations each providing wireless communication to a plurality of mobile phones positioned in a second telecommunications cell;

a second base station controller coupled with the second base stations for controlling operation thereof;

a second mobile switching center coupled with the second base station controller for managing and establishing calls destined for and originating from the mobile Dhones in the second telecommunications cell;

a dispatch mode controller operatively coupled with the first mobile switching center and coupled with the second mobile switching center via a public switched telephone network and configured for providing dispatch mode calling between a plurality of mobile phones in a pre-defined talk-group, the dispatch mode controller including a dispatch application processor operable to;

validate a dispatch mode call requested by an originating mobile phone in the talk-group;

determine location information for destination mobile phones in the talk-group;

receive voice packets from the originating mobile phone;

encode the voice packets;

provide information to the destination mobile phones that enables the destination mobile phones to decipher the encoded voice packets; and

route the encoded voice packets to the first base stations corresponding to the cells in which the destination mobile phones are located via the first mobile switching center and route the encoded voice packets to the second base stations corresponding to the cells in which the destination mobile phones are located via the public switched telephone network and the second mobile switching center.

6. The wireless network as set forth in claim 5, the dispatch mode controller further including a packet duplicator operable to duplicate the voice packets and to send the voice packets to the base stations when the destination mobile phones are being served by more than one base station.

7. A wireless network using code division multiple access techniques comprising:

a first telecommunications cell including

a plurality of base stations each providing wireless communication to a plurality of mobile phones positioned in the first telecommunications cell,

a base station controller coupled with the base stations for controlling operation thereof, and

a mobile switching center coupled with the base station controller for managing and establishing calls destined for and originating from the mobile phones in the first telecommunications cell;

a second telecommunications cell including

a plurality of base stations each providing wireless communication to a plurality of mobile phones positioned in the second telecommunications cell,

a base station controller coupled with the base stations for controlling operation thereof, and

a mobile switching center coupled with the base station controller for managing and establishing calls destined for and originating from the mobile phones in the second telecommunications cell; and

a dispatch mode controller coupled with the mobile switching center of the first telecommunications cell and indirectly coupled with the mobile switching center of the second telecommunications cell via a public switched telephone network, the dispatch mode controller being configured for providing dispatch mode calling between a plurality of mobile phones in a pre-defined talk group located in the first telecommunications cell and the second telecommunications cell.