Push-to-talk capacity enhancement

• US 9,232,365 B1
• Filed: 08/27/2013
• Issued: 01/05/2016
• Est. Priority Date: 08/27/2013
• Status: Expired due to Fees

• Current Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Original Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Inventors: Mansour, Nagi
• Primary Examiner(s): Orgad, Edan
• Assistant Examiner(s): Latorre, Ivan O
• Application Number:
  US14/011,583
• Time in Patent Office: 861 Days
• Field of Search: 370/312, 370/329, 370/390, 370/347, 370/342, 370/441, 455/518, 455/519, 455/90.2
• US Class Current: 1/1
• CPC Class Codes: H04J 13/10 Code generation
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04L 12/1859 adapted to provide push services, e.g. data channels
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/4061 Push-to services, e.g. push-to-talk or push-to-video
• CPC Class Codes: H04L 65/611 for multicast or broadcast systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06
• CPC Class Codes: H04W 4/08 User group management
• CPC Class Codes: H04W 4/10 Push-to-Talk [PTT] or Push-On-Call services
• CPC Class Codes: H04W 76/45 for Push-to-Talk [PTT] or Push-to-Talk over cellular [PoC] services

Abstract

Push-to-talk messages are sent via a wireless multicast channel to multiple push-to-talk groups of devices regardless of group membership. Thus, all of the devices using the multicast channel receive all of the push-to-talk messages. To separate messages bound for one push-to-talk group from those bound for another, a push-to-talk group specific orthogonal code is applied to each message. The devices in a specific group use the group specific orthogonal code to decode the received multicast messages. If a device decodes the multicast message with the correct group specific orthogonal code, then the message is decoded and the device can play the message. If a device decodes the multicast message with a different group specific code (i.e., because it is not a member of the group the message was intended for), the message is will not be properly decoded and thus will be unplayable or scrambled.

Claims

1. A method of operating a wireless device in a first push-to-talk (PTT) grouping of wireless devices, comprising:

in response to a command received from an access node, configuring a multicast session for transmission of a first encoded PTT multimedia message to the first PTT grouping of wireless devices and a second PTT grouping of wireless devices;

decoding the first encoded PTT multimedia message using a first orthogonal code, wherein validity of the first PTT multimedia message is determined based on a correlation of the first PTT multimedia message and the first orthogonal code; and

,

when the first PTT multimedia message is valid, configuring the wireless device to play the decoded PTT multimedia messages received via the multicast session.

2. The method of claim 1, wherein a decoder algorithm associated with the multicast session is used to determine whether the decoded first PTT multimedia message is valid.

3. The method of claim 1, further comprising:

receiving a second encoded PTT multimedia message from the access node via the multicast session; and

,

decoding the encoded second PTT multimedia message using the first orthogonal code to create decoded PTT multimedia message data.

4. The method of claim 3, further comprising:

determining that the second decoded PTT multimedia message data is invalid.

5. The method of claim 4, wherein a second correlation of the second decoded PTT multimedia message data and the first orthogonal code is used to determine that the second decoded PTT multimedia message data is invalid.

6. A communication system, comprising:

a push-to-talk (PTT) processing node configured to send, via a multicast session, a first encoded PTT multimedia messages to a first PTT grouping of wireless devices and a second PTT grouping of wireless devices, wherein the first PTT grouping of wireless devices is assigned a first orthogonal code and the second PTT grouping of wireless devices is assigned a second orthogonal code; and

,

a wireless access node configured to receive the first encoded PTT multimedia messages and forward, via a multicast channel, the first encoded PTT multimedia messages to at least one wireless device of the first PTT grouping of wireless devices and to a second wireless device of the second PTT grouping of wireless devices,

wherein the at least one wireless device of the first PTT grouping of wireless devices is configured to decode the first encoded PTT multimedia messages using first orthogonal code and determine, based on a first correlation of the first PTT multimedia message and the first orthogonal code, whether the first decoded PTT multimedia messages are valid, and

when the first PTT multimedia messages are valid, play the first decoded PTT multimedia messages received via the multicast session.

7. The communication system of claim 6, wherein the first encoded PTT multimedia messages are addressed by the PTT processing node to the first PTT grouping of wireless devices and a second encoded PTT multimedia messages is addressed to the second PTT grouping of wireless devices, and the wireless access node is also configured to encode, before forwarding via the multicast channel, the first PTT multimedia messages using the first orthogonal code and the second PTT multimedia messages using the second orthogonal code.

8. A method of operating a wireless communication system, comprising:

establishing a first push-to-talk (PTT) grouping of wireless devices and a second PTT grouping of wireless devices within a sector served by a first access node, wherein the first PTT grouping of wireless devices is assigned a first orthogonal code and the second PTT grouping of wireless devices is assigned a second orthogonal code in a same family of orthogonal codes;

transmitting, via a multicast session, a first PTT multimedia message over a specified channel, wherein the first PTT multimedia message is encoded with the first orthogonal code and received by each of the wireless devices in both the first PTT grouping of wireless devices and the second PTT grouping of wireless devices;

decoding, at the first PTT grouping of wireless devices, the encoded first PTT multimedia message using the first orthogonal code;

determining that the decoded first PTT multimedia message is valid based on a first correlation of the first PTT multimedia message and the first orthogonal code;

playing the decoded first PTT multimedia message to at least one wireless device in the first PTT grouping;

decoding, at the second PTT grouping of wireless devices, the first encoded PTT multimedia message using the second orthogonal code; and

determining that the decoded first PTT multimedia message is invalid based on a second correlation of the first PTT multimedia message and the second orthogonal code.

9. The method of claim 8, further comprising:

encoding a second PTT multimedia message addressed to the second PTT grouping of wireless devices by applying the second orthogonal code of to the second PTT multimedia message to create a second encoded PTT multimedia message; and

,

transmitting, via the multicast session, the second encoded PTT multimedia message to the first PTT grouping of wireless devices and the second PTT grouping of wireless devices.

10. The method of claim 8, further comprising:

configuring the first PTT grouping of wireless devices to decode the first PTT multimedia messages received via the multicast session using the first orthogonal code.

11. The method of claim 9, further comprising:

configuring the second PTT grouping of wireless devices to decode the second PTT multimedia messages received via the multicast session using the second orthogonal code.

12. The method of claim 8, further comprising:

receiving, by the first access node, the first PTT multimedia message addressed to the first PTT grouping of wireless devices, the first PTT multimedia message being unencoded when received by the access node.

13. The method of claim 8, wherein the at least one wireless device in the second PTT grouping of wireless devices determines the decoding of the first encoded PTT multimedia message using the second orthogonal code was unsuccessful.