System and method for efficient push-to-talk communications

• US 20060116149A1
• Filed: 11/29/2004
• Published: 06/01/2006
• Est. Priority Date: 11/29/2004
• Status: Active Grant

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: Chang, Henry, Dunn, Doug
• Granted Patent: US 7,437,170 B2
• Time in Patent Office: Days
• US Class Current: 455/518
• CPC Class Codes: H04W 4/10 Push-to-Talk [PTT] or Push-On-Call services
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 76/45 for Push-to-Talk [PTT] or Push-to-Talk over cellular [PoC] services
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

A system and method are provided for efficient push-to-talk (PTT) communications in a cellular network of wireless telephones. The method comprises the steps of: receiving a PTT session initiation in a cellular wireless telephone network; identifying a plurality of common PTT session mobile stations in close proximity as a group; assigning a shared forward link channel to the group; and transmitting a PTT statement on the shared channel via the forward link. The shared channel can be a shared traffic channel or a common channel, such as a broadcast channel, forward common control channel, or paging channel. The shared forward link channel may be in either a circuit-switched or IP packet data system. Further, the shared forward link channel, in addition to including a shared forward fundamental channel, may also include a shared forward supplemental channel.

Claims

1. In a cellular network of wireless telephones, a method for efficient push-to-talk (PTT) communications, the method comprising:

receiving a cellular wireless telephone network PTT session initiation;

identifying a plurality of common PTT session mobile stations in close proximity as a common PTT group in response to the cellular wireless telephone network PTT session initiation;

assigning a shared forward link channel to the common PTT group; and

transmitting a PTT statement on the shared channel via the shared forward link channel.

2. The method of claim 1 wherein identifying the plurality of common PTT session mobile stations in close proximity comprises identifying the plurality of common PPT session mobile stations in a sector.

3. The method of claim 1 wherein assigning the shared forward link channel comprises assigning at least one of a shared traffic channel and a common channel.

4. The method of claim 3 wherein assigning the common channel comprises assigning at least one of a broadcast channel, a control channel, and a paging channel.

5. The method of claim 1 wherein assigning the shared forward link channel comprises assigning a shared forward fundamental channel and a shared forward supplemental channel.

6. The method of claim 1 wherein assigning the shared forward link channel comprises assigning a shared Walsh code and a shared Public Long Code Mask (PLCM).

7. The method of claim 1 wherein identifying the plurality of common PTT session mobile stations comprises:

transmitting a PTT service parameters message;

receiving a Registration from a plurality of registering mobile stations; and

identifying the registering mobile stations as the plurality of common PTT session mobile stations.

8. The method of claim 1 wherein assigning the shared forward link channel comprises assigning at least one of a common time slot and a common frequency.

9. The method of claim 1 further comprising encrypting the PTT statement.

10. The method of claim 1 further comprising:

comparing a number of members in the common PTT group to an overall number of mobile stations using forward link traffic channels in a sector to establish a PTT forward call ratio;

comparing the PTT forward call ratio to a threshold; and

if the PTT forward call ratio exceeds the threshold, permitting higher data rates in the forward link to requesting mobile stations in the sector.

11. The method of claim 1 further comprising:

comparing a number of members in the common PTT group to an overall number of mobile stations using reverse link traffic channels in a sector to establish a PTT reverse call ratio;

comparing the PTT reverse call ratio to a threshold; and

if the PTT reverse call ratio exceeds the threshold, permitting higher data rates in the reverse link to requesting mobile stations in the sector.

12. The method of claim 11 wherein permitting higher data rates in the reverse link comprises setting a Reverse Activity Bit (RAB) to zero.

13. The method of claim 1 further comprising:

receiving a second PTT statement after the PTT statement transmission;

wherein identifying the plurality of common PTT session mobile stations further comprises re-identifying a second plurality of common PTT session mobile stations as a re-identified common PTT group;

wherein assigning the shared forward link channel comprises assigning a second shared forward link channel to the re-identified common PTT group; and

wherein transmitting the PTT statement comprises transmitting the second PTT statement on the second shared forward link channel.

14. In a cellular network of wireless telephones, a system for efficient push-to-talk (PTT) communications, the system comprising:

a base station (BS) having an air interface to support a common PTT session with a plurality of mobile stations;

a base station controller (BSC) having an interface with the BS, the BSC configured to identify a plurality of common PTT session mobile stations in close proximity as a common PTT group, and to send a PTT message to the BS; and

wherein the BS is configured to assign a shared forward link channel to the common PTT group, and to transmit a PTT statement including the PTT message on the shared forward link channel.

15. The system of claim 14 wherein the plurality of common PPT session mobile stations are located in a common sector.

16. The system of claim 14 wherein the shared forward link channel comprises at least one of a shared traffic channel and a common channel.

17. The system of claim 16 wherein the common channel comprises at least one of a broadcast channel, a control channel, and a paging channel.

18. The system of claim 14 wherein the shared forward link channel comprises a shared forward fundamental channel and a shared forward supplemental channel.

19. The system of claim 14 wherein the shared forward link channel comprises a shared Walsh code and a shared Public Long Code Mask (PLCM).

20. The system of claim 14 wherein the shared forward link channel comprises at least one of a common time slot and a common frequency.

21. The system of claim 14 wherein the BS is further configured to encrypt the PTT statement.

22. A mobile station operating in cellular network including a base station, the mobile station comprising:

an antenna;

a transceiver coupled to the antenna for communicating with the base station via an air interface, the mobile station further configured to;

receive a shared forward link channel assignment;

receive a PTT statement on the shared forward link channel; and

decode the PTT statement.

23. The mobile station of claim 22 wherein the shared forward link channel assignment is transmitted by the base station to a second mobile station.

24. The mobile station of claim 22 wherein the shared forward link channel comprises at least one of a shared traffic channel and a common channel.

25. The mobile station of claim 24 wherein the common channel comprises at least one of a broadcast channel, a control channel, and a paging channel.

26. The mobile station of claim 22 wherein the shared forward link channel comprises a shared forward fundamental channel and a shared forward supplemental channel.

27. The mobile station of claim 22 wherein the shared forward link channel comprises a shared Walsh code and a shared Public Long Code Mask (PLCM).

28. The mobile station of claim 22 wherein the shared forward link channel comprises at least one of a common time slot and a common frequency.

29. The mobile station of claim 22 wherein the mobile station is further configured to decrypt the PTT statement.

30. The mobile station of claim 22 wherein the mobile station is further configured to:

receive a PTT service parameters message; and

transmit Registration in response to the PTT service parameter message, the shared forward link channel assignment based at least in part on the Registration.