WIRELESS COMMUNICATIONS SYSTEM AND METHOD

• US 20140226558A1
• Filed: 08/09/2012
• Published: 08/14/2014
• Est. Priority Date: 08/19/2011
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: SCA IPLA Holdings Incorporated (Sony Group Corp.)
• Inventors: Speight, Timothy James, Piggin, Paul William
• Granted Patent: US 9,532,357 B2
• Time in Patent Office: Days
• US Class Current: 370/315
• CPC Class Codes: H04B 7/15 Active relay systems
• CPC Class Codes: H04B 7/155 Ground-based stations H04B7/204 takes precedence
• CPC Class Codes: H04B 7/204 Multiple access
• CPC Class Codes: H04L 67/303 Terminal profiles
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 52/221 using past power control commands
• CPC Class Codes: H04W 52/228 using past power values or information
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 56/005 compensating for timing error by adjustment in the receiver
• CPC Class Codes: H04W 72/0473 the resource being transmission power
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 74/004 in the uplink, i.e. towards network
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 84/047 using dedicated repeater stations

Abstract

A wireless communications system includes a base station, a relay device, and a terminal device. The terminal device can transmit one or more first type access request messages to request uplink resources from the base station, and if no response to the first type access request messages is received from the base station, can transmit a second type access request message. The base station is responsive to a first type access request message received from the terminal device to transmit an allocation of uplink resources to the terminal device. The relay device is responsive to a second type access request message received from the terminal device to transmit a relayed access request message to request the base station to allocate uplink resources to the terminal device. The base station is responsive to the relayed access request message to transmit an allocation of uplink resources to the terminal device.

Claims

1. A wireless communications system, comprising:

a base station;

a relay device; and

a terminal device;

wherein

the terminal device is operable

to transmit one or more access request messages of a first type to request uplink resources from the base station, and

if no response to the transmitted access request messages of the first type is received from the base station, to transmit an access request message of a second type;

the base station is responsive to an access request message of the first type received from the terminal device to transmit an allocation of uplink resources to the terminal device;

the relay device is responsive to an access request message of the second type received from the terminal device to transmit a relayed access request message to the base station to request the base station to allocate uplink resources to the terminal device; and

the base station is responsive to the relayed access request message from the relay device to transmit an allocation of uplink resources to the terminal device.

2. A wireless communications system according to claim 1, wherein

the terminal device is operable to transmit uplink data to the relay device on the allocated uplink resources;

and

the relay device is operable to relay to the base station the uplink data received from the terminal device.

3. A wireless communications system according to claim 1, wherein the terminal device is operable

to repeatedly transmit access request messages of the first type at successively higher power levels until a response is received from the base station or until a maximum power level is reached;

and

if no response to the access request message of the first type at the maximum power level is received from the base station, to transmit the access request message of the second type.

4. A wireless communications system according to claim 3, wherein the access request message of the second type is transmitted at the maximum power level.

5. A wireless communications system according to claim 3, wherein the maximum power level for transmitting the access request messages of the first type is less than the maximum transmission power of the terminal device.

6. A wireless communications system according to claim 1, wherein

the relay device is operable to determine an identifier for the terminal device from which the access request message of the second type was received and include the identifier in the relayed access request message transmitted to the base station;

and

the base station uses the identifier to transmit an allocation of uplink resources to the terminal device.

7. A wireless communications system according to claim 6, wherein

the access request messages are transmitted on a random access channel;

and

the relay device is operable to determine an identifier for the terminal device from the time and/or frequency resource within the random access channel used to transmit the access request message of the second type.

8. A wireless communications system according to claim 1, wherein

the relay device is operable

to measure a received signal power of the access request message of the second type received from the terminal device;

and

to set power control information in the relayed access request message for controlling a power level of a subsequent transmission from the terminal device to the relay device on the allocated uplink resources.

9. A wireless communications system according to claim 8, wherein the power control information specifies a power offset from the received signal power of the access request message of the second type.

10. A wireless communications system according to claim 8, wherein the allocation of uplink resources transmitted from the base station to the terminal device comprises the power control information for controlling the transmission power of the subsequent transmission from the terminal device to the relay device.

11. A wireless communications system according to claim 1, wherein

the relay device is operable

to measure a propagation time delay between the terminal device and the relay device of the access request message of the second type;

to determine, based on the propagation time delay, a required timing advance offset for a subsequent transmission from the terminal device to the relay device so that a receive time of the subsequent transmissions at the relay device is synchronised with a receive time of transmissions from other terminal devices; and

to specify said timing advance offset in the relayed access request message.

12. A wireless communications system according to claim 11, wherein the allocation of uplink resources transmitted from the base station to the terminal device comprises the timing advance offset for controlling the timing of a subsequent transmission from the terminal device to the relay device.

13. A wireless communications system according to claim 1, wherein the relayed access request message comprises an identification of the terminal device which transmitted the message.

14. A wireless communications system according to claim 1, wherein

the relay device is responsive to an access request message of the second type received from the terminal device to request the base station to allocate uplink resources to the relay device to transmit the relayed access request message;

the base station is responsive to the request from the base station to allocate uplink resources to the relay device; and

the relay device is operable to transmit the relayed access request message to the base station using the uplink resources allocated to the relay device by the base station.

15. A wireless communications system according to claim 2, wherein

the access request messages of the first type are Random Access Channel preambles selected from a first group of Random Access Channel preambles;

the access request messages of the second type are Random Access Channel preambles selected from a second group of Random Access Channel preambles;

the allocation of uplink resources transmitted from the base station to the terminal device is a Random Access Response; and

the uplink data transmitted by the terminal device on the allocated uplink resources is a Message 3.

16. A wireless communications system according to claim 2, wherein the uplink data comprises one or both of control information and data.

17. A wireless communications system according to claim 2, wherein

the relay device is operable

to measure a received signal power of the uplink data received from the terminal device;

and

to set power control information in the relayed uplink data for controlling a power level of a subsequent transmission from the terminal device to the relay device.

18. A wireless communications system according to claim 2, wherein

the relay device is operable

to measure a propagation time delay between the terminal device and the relay device of the uplink data;

to determine, based on the propagation time delay, a required timing advance offset for a subsequent transmission from the terminal device to the relay device so that a receive time of the subsequent transmission at the relay device is synchronised with a receive time of transmissions from other terminal devices; and

to specify said timing advance offset in the relayed uplink data.

19. A wireless communications system according to claim 2, wherein the relayed uplink data comprises an identification of the terminal device which transmitted the uplink data.

20. A wireless communications system according to claim 2, wherein

the relay device is responsive to the uplink data received from the terminal device to request the base station to allocate uplink resources to the relay device to transmit the relayed uplink data;

the base station is responsive to the request from the base station to allocate uplink resources to the relay device; and

the relay device is operable to transmit the relayed uplink data to the base station using the uplink resources allocated to the relay device by the base station.

21. A wireless communications system according to claim 1, wherein

the base station is responsive to receiving relayed access request messages from plural relay devices in relation to the same access request message of the second type to:

select one of the relay devices to serve the terminal device; and

to inform the selected relay device that it is to serve as the relay device for the terminal device.

22. A wireless communications system according to claim 21, wherein

the relayed access request message comprises an indication of the received power level of the access request message of the second type;

and

the base station is operable to select as the serving relay device the relay device having received the access request message of the second type at the highest power level.

23. A wireless communications system according to claim 22, wherein

if two or more of the plural relay devices received the access request message of the second type at substantially the same power level, the base station is operable to select as the serving relay device the relay device, of those having received the access request message of the second type at substantially the same power level, which is currently serving the fewest terminal devices.

24. A wireless communications system according to claim 21, wherein

the base station transmits a negative acknowledgement message to those of the plural relay devices not selected to serve the terminal device.

25. A wireless communications system according to claim 24, wherein

the negative acknowledgement message is transmitted via a group identifier to all of the plural relay devices;

and

the relay device selected as the serving relay device is responsive to being informed by the base station that it is to be the serving relay device to ignore the negative acknowledgement message.

26. A method of wirelessly communicating data from a terminal device to a base station via a relay device, comprising:

transmitting one or more access request messages of a first type from the terminal device to request uplink resources from the base station, and

if no response to the transmitted access request messages of the first type is received at the terminal device from the base station, transmitting an access request message of a second type from the terminal device to the base station;

responsive to an access request message of the first type being received at the base station from the terminal device, transmitting from the base station an allocation of uplink resources to the terminal device;

responsive to an access request message of the second type being received at the relay device from the terminal device, transmitting from the relay device a relayed access request message to the base station to request the base station to allocate uplink resources to the terminal device; and

responsive to the relayed access request message being received at the base station from the relay device, transmitting from the base station an allocation of uplink resources to the terminal device.

27. A method of receiving, at a base station, wireless communications from a terminal device via a relay device, comprising:

responsive to access request message of a first type being received from the terminal device, transmitting an allocation of uplink resources to the terminal device; and

responsive to a relayed access request message from the relay device requesting the base station to allocate uplink resources to the terminal device being received, transmitting an allocation of uplink resources to the terminal device, the relayed access request message being transmitted from the relay device to the base station in response to an access request message of a second type being received at the relay device;

wherein

the access request message of the second type is transmitted by the terminal device if no response to the transmitted access request message of the first type is received from the base station.

28. A base station for receiving wireless communications from a terminal device via a relay device, the base station comprising:

a receiver; and

a transmitter, responsive to access request message of a first type being received at the receiver from the terminal device to transmit an allocation of uplink resources to the terminal device; and

responsive to a relayed access request message from the relay device requesting the base station to allocate uplink resources to the terminal device being received at the receiver to transmit an allocation of uplink resources to the terminal device, the relayed access request message being transmitted from the relay device to the base station in response to an access request message of a second type being received at the relay device;

wherein

the access request message of the second type is transmitted by the terminal device if no response to the transmitted access request message of the first type is received from the base station.

29-34. -34. (canceled)