Transmission timing in a carrier group
Transmission timing of a random access preamble in an uplink carrier of a carrier group being determined employing a synchronization signal transmitted on a downlink carrier of the carrier group. The wireless device receives a time alignment command from the base station. The time alignment command comprises a time adjustment value and an index identifying the carrier group. The wireless device applies the time adjustment value to uplink signals transmitted on all activated uplink carriers in the carrier group.
1. A wireless device comprising:
a) one or more processors; and
b) memory storing instructions that, when executed by said one or more processors, cause said wireless device to:
i) receive at least one radio resource control message comprising:
(1) configuration parameters of a first carrier and at least one second carrier; and
(2) a carrier group index for a second carrier in said at least one second carrier, said carrier group index identifying a carrier group, said carrier group being one of a plurality of carrier groups, said carrier group comprising a subset of said at least one second carrier;
ii) receive a control command causing said wireless device to transmit a random access preamble on said second carrier;
iii) transmit said random access preamble on said second carrier, transmission timing of said random access preamble being determined, at least in part, employing a synchronization signal transmitted on a downlink carrier in said carrier group, uplink transmissions in said carrier group employing said synchronization signal as timing reference;
iv) receive a time alignment command comprising a time adjustment value and said-carrier group index; and
v) apply said time adjustment value to uplink signals transmitted on all activated uplink carriers in said carrier group.
2. The wireless device of claim 1 , wherein said control command is received on a scheduling carrier of said second carrier.
3. The wireless device of claim 2 , wherein said control command further comprises a carrier index identifying said second carrier.
4. The wireless device of claim 1 , wherein said control command further comprises a power control command.
5. The wireless device of claim 1 , wherein said control command is scrambled using an identifier of said wireless device.
6. The wireless device of claim 1 , wherein said control command is received in response to said wireless device transmitting a buffer status report to said base station, said buffer status report comprising a buffer size, said buffer size indicating an amount of data available for transmission in buffers of said wireless device.
7. The wireless device of claim 1 , wherein said control command further comprises a mask index employed by said wireless device to determine transmission timing or transmission resources of said random access preamble.
8. A method for use in a wireless device, said method comprising:
a) receiving at least one radio resource control message comprising:
i) configuration parameters of a first carrier and at least one second carrier; and
ii) a carrier group index for a second carrier in said at least one second carrier, said carrier group index identifying a carrier group, said carrier group being one of a plurality of carrier groups, said carrier group comprising a subset of said at least one second carrier;
b) receiving a control command causing said wireless device to transmit a random access preamble on said second carrier;
c) transmitting said random access preamble on said second carrier, transmission timing of said random access preamble being determined, at least in part, employing a synchronization signal transmitted on a downlink carrier in said carrier group, uplink transmissions in said carrier group employing said synchronization signal as timing reference;
d) receiving a time alignment command comprising a time adjustment value and said carrier group index; and
e) applying said time adjustment value to uplink signals transmitted on all activated uplink carriers in said carrier group.
9. The method of claim 8 , wherein said control command is received on a scheduling carrier of said second carrier.
10. The method of claim 9 , wherein said control command further comprises a carrier index identifying said second carrier.
11. The method of claim 8 , wherein said control command further comprises a power control command.
12. The method of claim 8 , wherein said control command is scrambled using an identifier of said wireless device.
13. The method of claim 8 , wherein said control command is received in response to said wireless device transmitting a buffer status report to said base station, said buffer status report comprising a buffer size, said buffer size indicating an amount of data available for transmission in buffers of said wireless device.
14. The method of claim 8 , wherein said control command further comprises a mask index employed by said wireless device to determine transmission timing or transmission resources of said random access preamble.
15. A base station comprising:
a) one or more processors; and
b) memory storing instructions that, when executed by said one or more processors, cause said base station to:
i) transmit at least one radio resource control message comprising:
(1) configuration parameters of a first carrier and at least one second carrier; and
(2) a carrier group index for a second carrier in said at least one second carrier, said carrier group index identifying a carrier group, said carrier group being one of a plurality of carrier groups, said carrier group comprising a subset of said at least one second carrier;
ii) transmit a control command causing said wireless device to transmit a random access preamble on said second carrier;
iii) receive said random access preamble on said second carrier, transmission timing of said random access preamble being determined, at least in part, employing a synchronization signal transmitted on a downlink carrier in said carrier group, uplink transmissions in said carrier group employing said synchronization signal as timing reference; and
iv) transmit a time alignment command comprising a time adjustment value and said carrier group index; and
wherein said time alignment command causes substantial alignment of reception timing of uplink signals in frames and subframes of said carrier group.
16. The base station of claim 15 , wherein said control command is transmitted on a scheduling carrier of said second carrier.
17. The base station of claim 16 , wherein said control command further comprises a carrier index identifying said second carrier.
18. The base station of claim 15 , wherein said control command further comprises a power control command.
19. The base station of claim 15 , wherein said control command is scrambled using an identifier of said wireless device.
20. The base station of claim 15 , wherein said control command is transmitted in response to said base station receiving a buffer status report from said wireless device, said buffer status report comprising a buffer size, said buffer size indicating an amount of data available for transmission in buffers of said wireless device.