Random access channel enhancement for carrier aggregation with different uplink/downlink configuration

Patent metadata

Field	Value
Publication number	US-9491781-B2
Application number	US-201214375887-A
Country	US
Kind code	B2
Filing date	Feb 1, 2012
Priority date	Feb 1, 2012
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

The present invention relates to methods, apparatuses and a computer program product for random access channel enhancement for carrier aggregation with different uplink/downlink configuration. The present invention includes detecting, at a user equipment, a downlink control channel in a specific downlink subframe on a first component carrier, receiving, at the user equipment, a downlink shared channel on the first component carrier, and transmitting, after a predetermined period, a random access channel in a specific uplink subframe on a second component carrier, the specific uplink subframe overlapping the specific downlink subframe on the first component carrier.

First claim

What is claimed is:

1. An apparatus, comprising:
circuitry configured to
detect a downlink control channel in a specific downlink subframe on a first component carrier;
receive a downlink shared channel on the first component carrier; and
transmit, after a predetermined guard period that follows the reception of the downlink shared channel on the first component carrier, a random access channel within one or more symbols remaining in a specific uplink subframe on a second component carrier, the specific uplink subframe overlapping with the specific downlink subframe on the first component carrier.

2. The apparatus according to claim 1 , wherein the downlink shared channel has a short format according to a downlink pilot time slot field.

3. The apparatus according to claim 1 , wherein the random access channel has a short format according to physical random access channel format 4 for a time division duplex special subframe.

4. The apparatus according to claim 1 , wherein the overlapped specific uplink subframe and specific downlink subframe are predefined by a base station by higher layer signaling.

5. The apparatus according to claim 4 , wherein the higher layer signaling is radio resource controller (RRC) signaling.

6. The apparatus according to claim 1 , wherein the downlink control channel is a physical downlink shared channel (PDSCH).

7. The apparatus according to claim 6 , wherein the circuitry is configured to find, on the first component carrier through blind detection prior to detection of the PDSCH, a downlink grant that schedules the PDSCH in the specific downlink subframe.

8. The apparatus according to claim 1 , wherein the specific uplink subframe and the specific downlink subframe overlap by time domain multiplexing.

9. The apparatus according to claim 1 , wherein the circuitry is configured to find, on the first component carrier through blind detection prior to detection of the downlink control channel, a downlink grant that schedules the downlink control channel in the specific downlink subframe.

10. An apparatus, comprising:
circuitry configured to
determine that a random access preamble is to be transmitted to a base station in a specific uplink subframe on a first component carrier;
transmit, to a base station, in an uplink subframe on a second component carrier preceding the specific uplink subframe on the first component carrier, an indication that a random access preamble is transmitted in the specific uplink subframe on the first component carrier;
transmit the random access preamble in the specific uplink subframe on the first component carrier;
determine that a random access message 3 is to be transmitted to the base station in the specific uplink subframe on the first component carrier; and
transmit, to the base station, the random access message 3 in the specific uplink subframe on the first component carrier.

11. The apparatus according to claim 10 , wherein the indication is transmitted in an uplink control channel.

12. The apparatus according to claim 11 , wherein the uplink control channel is predefined by the base station.

13. The apparatus according to claim 10 , wherein the indication is transmitted in a Medium Access Control Control Element (MAC CE) with uplink data transmission in an uplink data channel.

14. The apparatus according to claim 13 , wherein the uplink data channel is predefined by the base station.

15. The apparatus according to claim 10 , wherein
the circuitry is of a user equipment for which the secondary component carrier is a primary component carrier and the first component carrier is a secondary component carrier, and
the circuitry is configured to be triggered by the base station for a contention based random access procedure on the secondary component carrier for uplink synchronization.

16. The apparatus according to claim 10 , wherein the indication comprises at least one of:
location of the specific uplink subframe in which the random access preamble is to be transmitted;
the random access preamble to be transmitted; and
a resource on which the random access message 3 is to be transmitted.

17. An apparatus, comprising:
circuitry configured to
receive, from a user equipment, an indication indicating that a random access preamble is transmitted to a base station in a specific uplink subframe on a first component carrier;
determine not to schedule downlink transmission in a downlink subframe on a second component carrier overlapping the specific uplink subframe on the first component carrier; and
receive, from the user equipment, a random access message 3 in the specific uplink subframe on the first component carrier.

18. The apparatus according to claim 17 , wherein the indication is received in an uplink control channel.

19. The apparatus according to claim 18 , wherein the circuitry is further configured to predefine the uplink control channel for such indications that a random access preamble is to be transmitted.

20. The apparatus according to claim 17 , wherein
the circuitry is of a base station,
the secondary component carrier is a primary component carrier for the user equipment and the first component carrier is a secondary component carrier for the user equipment, and
the circuitry is further configured to trigger the user equipment for a contention based random access procedure on the secondary component carrier for uplink synchronization, and receive the indication from the user equipment in response to the trigger.

Assignees

• Han Jing
• Bai Wei
• Zeng Erlin
• Gao Chunyan
• Wang Haiming
• Hong Wei
• Broadcom Corp

Inventors

• Han Jing
• Bai Wei
• Zeng Erlin
• Gao Chunyan
• Wang Haiming
• Hong Wei

Classifications

• H04W74/0866 Primary

  using a dedicated channel for access · CPC title

• H04W72/23

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04W72/21

  in the uplink direction of a wireless link, i.e. towards the network · CPC title

• H04W74/0833 Primary

  Random access procedures, e.g. with 4-step access · CPC title

• H04W72/042

  Electricity · mapped topic