Medium access control layer for packetized wireless systems

• US 6,532,225 B1
• Filed: 07/27/1999
• Issued: 03/11/2003
• Est. Priority Date: 07/27/1999
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Sollenberger, Nelson R., Chawla, Kapil K., Chuang, Justin C., Chang, Li Fung, Qiu, Xiaoxin
• Primary Examiner(s): Yao, Kwang Bin
• Assistant Examiner(s): JONES, PRENELL P
• Application Number:
  US09/361,572
• Time in Patent Office: 1,323 Days
• Field of Search: 370/341-349, 370/331-338, 370/403, 370/294-296, 370/524, 370/525, 370/432, 370/276, 370/312, 370/478, 370/337, 370/466-468, 370/392, 455/12.1, 455/442, 455/434-436, 455/458, 455/426-428, 455/503, 455/403, 455/433, 455/466, 455/517, 455/552
• US Class Current: 370/341
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 72/00 Local resource management
• CPC Class Codes: H04W 74/00 Wireless channel access
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An arrangement where, in addition to the control channels that are used to set up sessions, there is a logically and physically separate and independent set of control channels that can be used as session control channels. Illustratively, the physical GSM frame arrangement that employs 8 logical slots is used, with one slot both in the uplink and downlink dedicated to these separate control channels. In the downlink, such a control channel provides channel grant information, requests to make and transmit power measurements, poll mobile units, etc. In the uplink, such a control channel can be used to request access to a traffic channel, to report on power measurements, to request special hand-off handling, to respond to polling, etc. Because the uplink session control channel does not need to carry a significant amount of information, the GSM slot can be divided into minislots, with each minislot constituting a session control channel for a group of mobile units.

Claims

1. A method for a mobile unit to communicate with a base station over a wireless medium comprising the steps of:

sending a call set-up request message to the base station over a first control channel between said mobile unit and said base station, for said base station to enable two-way packet communication between said mobile unit and said base station over a traffic channel,

receiving information pertaining to a session control channel, established by said base station, that is logically distinct from said first control channel and also physically and logically distinct from said traffic channel, and

said mobile unit sending a request over said session control channel for access to said traffic channel for said session to enable said mobile unit to send said packet traffic to said base station over said traffic channel, where said request identifies the call that requests a packet traffic channel by a traffic flow identifier that was provided to said mobile unit over said first control channel.

7. The method of claim 1 further comprising a step of receiving control information over said session control channel, and said mobile unit analyzing whether control information received in said step of receiving is a packet traffic channel grant message or some other control message from a preselected set of control messages.

8. The method of claim 1 further comprising a step of sending packet data over said traffic channel when said control information corresponds to a packet traffic channel grant message.

9. The method of claim 8 where, in response to an end of a session, said mobile unit proceeds with different actions, based on whether said session is a “

best effort”

data communications session, a delay-sensitive data communications session, or a real-time communications application.

10. The method of claim 9 where said different actions also depend on whether access by said mobile unit to said session control channel is via a random access protocol, a fixed dedicated channel, or a dynamically assignable dedicated channel.

11. The method of claim 1 further comprising a step of receiving a polling message from said base station over said session control channel.

12. The method of claim 11 where said polling message requests power measurement information.

13. The method of claim 11 further comprising a step of sending information in response to said polling message.

14. The method of claim 13 where said information in response to said polling message is a request for a traffic channel.

15. The method of claim 11 further comprising a step of sending information in response to said polling message only when information responsive to said polling message is available.

2. A method for a mobile unit to communicate with a base station over a wireless medium comprising the steps of:

sending a call set-up request message to the base station over a first control channel between said mobile unit and said base station, for said base station to enable two-way packet communication between said mobile unit and said base station over a traffic channel, and

receiving information pertaining to a session control channel, established by said base station, that is logically distinct from said first control channel and also physically and logically distinct from said traffic channel, where said information regarding a session control channel informs said mobile unit that in order to gain access to said session control channel said mobile unit is to employ a random access protocol.

3. A method for a mobile unit to communicate with a base station over a wireless medium comprising the steps of:

sending a call set-up request message to the base station over a first control channel between said mobile unit and said base station, for said base station to enable two-way packet communication between said mobile unit and said base station over a traffic channel, and

receiving information pertaining to a session control channel, established by said base station, that is logically distinct from said first control channel and also physically and logically distinct from said traffic channel, where said information regarding a session control channel informs said mobile unit that in order to gain access to said session control channel said mobile unit is to employ a contention-based protocol.

4. A method for a mobile unit to communicate with a base station over a wireless medium comprising the steps of:

sending a call set-up request message to the base station over a first control channel between said mobile unit and said base station, for said base station to enable two-way packet communication between said mobile unit and said base station over a traffic channel, and

receiving information pertaining to a session control channel, established by said base station, that is logically distinct from said first control channel and also physically and logically distinct from said traffic channel, where said information regarding a session control channel fixedly assigns a fast-packet data access channel, over which said mobile unit can request fast access for a traffic channel, that is valid for duration of said call.

6. The method of claim 4 further comprising a step of receiving control information over said session control channel.

5. A method for a mobile unit to communicate with a base station over a wireless medium comprising the steps of:

sending a call set-up request message to the base station over a first control channel between said mobile unit and said base station, for said base station to enable two-way packet communication between said mobile unit and said base station over a traffic channel, and

receiving information pertaining to a session control channel, established by said base station, that is logically distinct from said first control channel and also physically and logically distinct from said traffic channel, where said information regarding a session control channel dynamically assigns a fast-packet data access channel, over which said mobile unit can request fast access for a traffic channel, that is valid until said mobile unit enters a state in which a packet traffic channel from said mobile unit to said base station is relinquished.

16. A method for a mobile unit to communicate with a base station over a wireless medium comprising the steps of:

sending a call set-up request message to the base station over a first control channel between said mobile unit and said base station, for said base station to enable two-way packet communication between said mobile unit and said base station over a traffic channel, and

receiving information pertaining to a session control channel, established by said base station, that is logically distinct from said first control channel and also physically and logically distinct from said traffic channel, where said communication is passed by said medium in frames said session control channel is positioned in one or more channels of said frames, each frame having N logical channels, where N is an integer, and other logical channels of said N logical channels are used for packet traffic channels.

17. The method of claim 16 where said one or more channels are one or more time slots, and said N channels are N time slots.

18. The method of claim 16 where said one logical channel is divided into two minislots, and each of said minislots is available for sending control messages.

19. The method of claim 16 where said mobile unit interacts over said session control channel and, concurrently, is participating in an ongoing data transfer over a packet traffic channel.

20. The method of claim 16 where said mobile unit is adapted to interact over said session control channel during said one or more channels of other than consecutive frames, and to interact over a packet traffic channel of other than consecutive frames, where said other than consecutive frames for interaction over said session control channel are distinct from said other than consecutive frames for interaction over said packet traffic channel.

21. A method for a mobile unit to communicate with a base station over a wireless medium comprising the steps of:

sending a call set-up request message to the base station over a first control channel between said mobile unit and said base station, for said base station to enable two-way packet communication between said mobile unit and said base station over a traffic channel, and

receiving information pertaining to a session control channel, established by said base station, that is logically distinct from said first control channel and also physically and logically distinct from said traffic channel, where said session control channel is positioned in one logical time slot of other than consecutive frames having N logical time slots, where N is an integer and in another logical time slot in other frames, where other logical time slots of said N logical time slots are used for packet traffic channels.

22. The method of claim 21 where said mobile unit is adapted to select whether to interact over said session control channel during said one logical time slot of alternating frames, or during said another logical time slot in other frames.