Random Access Process in a Multicarrier Base Station and Wireless Device

• US 20130188612A1
• Filed: 01/23/2013
• Published: 07/25/2013
• Est. Priority Date: 01/25/2012
• Status: Active Grant

• Current Assignee: Comcast Cable Communications LLC (Comcast Corporation)
• Original Assignee: Ofinno Technologies, LLC
• Inventors: Dinan, Esmael Hejazi
• Granted Patent: US 9,237,537 B2
• Time in Patent Office: Days
• US Class Current: 370/336
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/52 based on load
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal

Abstract

A Base station transmits a control command for transmission of a random access preamble on a first cell if the base station determines radio resources of the first cell are required for transmission of a portion of data and that the first cell requires a different uplink timing from all currently activated cells of the wireless device. The base station transmits at least one control packet for providing transport format information and resource allocation information for transmission of a plurality of packets of the data to be transmitted on a first data channel of the first cell.

Claims

1. A method comprising:

a) receiving, by a base station configured to communicate employing a plurality of cells with a wireless device, a buffer status report on a first cell in at least one activated cell in said plurality of cells from said wireless device, said buffer status report indicating an amount of data available for transmission in at least one uplink buffer of said wireless device, each of said at least one activated cell being assigned by said base station to a cell group in at least one first cell group;

b) transmitting, by said base station, a control command for transmission of a random access preamble on a second cell in said plurality of cells if said base station determines;

i) based at least in part on said buffer status report, that radio resources of said second cell are required for transmission of a portion of said data; and

ii) that said second cell requires a first uplink timing that is different from a second uplink timing of each of said at least one first cell group;

c) receiving, by said base station, said random access preamble on said second cell, said second cell being assigned to a second cell group, transmission timing of said random access preamble determined at least in part on a synchronization signal transmitted on an activated cell of said second cell group;

d) transmitting, a random access response on a primary cell of a primary cell group in said at least one first cell group, said random access response comprising a timing advance command for said second cell group; and

e) transmitting, by said base station, at least one control packet to provide transport format information and resource allocation information for transmission of a plurality of packets of said data to be transmitted on a first data channel of said second cell.

2. The method of claim 1, wherein said plurality of cells are assigned to a plurality of cell groups comprising:

a) said at least one first cell group; and

b) said second cell group.

3. The method of claim 1, further comprising transmitting an activation command to activate said second cell in said wireless device.

4. The method of claim 1, further comprising transmitting at least one control message configured to cause configuration of said second cell in said wireless device.

5. The method of claim 1, further comprising transmitting, by said base station, at least one control message to said wireless device, said at least one first control message configured to cause in said wireless device:

a) configuration of said second cell in said plurality of cells; and

b) assignment of said second cell to said second cell group.

6. The method of claim 1, wherein said activated cell of said second cell group is said second cell.

7. The method of claim 1, wherein control command comprises:

a) a mask index; and

b) said random access preamble identifier.

8. The method of claim 1, wherein:

a) said primary cell group comprises a first subset of said plurality of cells, said first subset comprising said primary cell, uplink transmissions by said wireless device in said primary cell group employing a first synchronization signal transmitted on said primary cell; and

b) said second cell group comprises a second subset of said plurality of cells, said second subset comprising an active secondary cell, uplink transmissions in said secondary cell group employing a second synchronization signal on said active secondary cell as a secondary timing reference.

9. A method comprising:

a) transmitting, by a base station configured to communicate employing a plurality of cells with a wireless device, at least one control message on a first cell in at least one activated cell in said plurality of cells, said at least one control message establishing at least one radio bearer, said at least one radio bearer enabling uplink data transmission with a guaranteed bit rate from said wireless device, each of said at least one activated cell being assigned by said base station to a cell group in at least one first cell group;

b) transmitting, by said base station, a control command for transmission of a random access preamble on a second cell in said plurality of cells if said base station determines;

i) based at least in part on said guaranteed bit rate, that radio resources of said second cell are required for transmission of a portion of said uplink data; and

ii) that said second cell requires a first uplink timing that is different from a second uplink timing of each of said at least one first cell group;

c) receiving, by said base station, said random access preamble on said second cell, said second cell being assigned to a second cell group, transmission timing of said random access preamble determined at least in part on a synchronization signal transmitted on an activated cell of said second cell group;

d) transmitting, by said base station, a random access response, said random access response comprising a timing advance command for said second cell group; and

e) transmitting, by said base station, at least one control packet to provide transport format information and resource allocation information for transmission of a plurality of packets of said uplink data to be transmitted on a first data channel of said second cell.

10. The method of claim 9, wherein said at least one control message is further configured to modify a radio bearer.

11. The method of claim 9, wherein said random access preamble is received on uplink random access resources of said second cell.

12. The method of claim 11, further comprising transmitting at least one control message by said base station to said wireless device, said control message causing configuration of said uplink random access resources.

13. The method of claim 12, wherein said at least one control message comprises a plurality of random access resource parameters, said plurality of random access resource parameters comprise an index, a frequency offset, and a plurality of sequence parameters.

14. The method of claim 9, further comprising transmitting, by said base station, at least one timing advance command to said wireless device, said timing advance command comprising:

a) a time adjustment value; and

b) an index identifying said second cell group; and

wherein said at least one timing advance command causes substantial alignment of reception timing of uplink signals in frames and subframes of said second cell group at said base station.

15. A base station, configured to communicate employing a plurality of cells with a wireless device, comprising:

a) one or more communication interfaces;

b) one or more processors; and

c) memory storing instructions that, when executed, cause said base station to;

i) receive a buffer status report indicating an amount of data available for transmission in at least one uplink buffer of said wireless device;

ii) transmit a control command for transmission of a random access preamble on a secondary cell in said plurality of cells if said base station determines;

(1) based at least in part on said buffer status report, that radio resources of said secondary cell are required for transmission of a portion of said data; and

(2) that said secondary cell requires a different uplink timing from currently activated and synchronized cells of said wireless device;

iii) receive said random access preamble on said secondary cell, said secondary cell being assigned to a secondary cell group in a plurality of cell groups, transmission timing of said random access preamble determined at least in part on a synchronization signal transmitted on an activated cell of said secondary cell group;

iv) transmit a random access response, said random access response comprising a timing advance command for said secondary cell group; and

v) transmit at least one control packet for providing transport format information and resource allocation information for transmission of a plurality of packets of said data to be transmitted on a first data channel of said second cell.

16. The base station of claim 15, wherein said instructions further cause said base station to transmit an activation command to activate said second cell in said wireless device.

17. The base station of claim 15, wherein said instructions further cause said base station to transmit at least one control message configured to cause configuration of said second cell in said wireless device.

18. The base station of claim 15, wherein said instructions further cause said base station to receive a second plurality of packets of said data on said currently activated and synchronized cells.

19. The base station of claim 15, wherein said at least one control message comprises at least one radio resource control message.

20. The base station of claim 15, wherein said control command further comprises an index identifying said secondary cell if said control command is not transmitted on a downlink carrier of said secondary cell.