Uplink scrambling during random access

Patent metadata

Field	Value
Publication number	US-9949239-B2
Application number	US-201414244580-A
Country	US
Kind code	B2
Filing date	Apr 3, 2014
Priority date	Aug 8, 2007
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

The technology described in this case facilitates random access by a user terminal with a radio base station. A user terminal determines one of a first type of uplink scrambling sequences and generates a random access message using the determined one of the first type of uplink scrambling sequences. The random access message is transmitted to the base station. The user terminal receives from the base station a second, different type of uplink scrambling sequence and uses it for subsequent communication with the radio base station. For example, the first uplink scrambling sequences may be specifically associated with the radio base station's cell area or a random access radio channel associated with the radio base station, but they are not specifically assigned to any user terminal, and the second uplink scrambling sequence may be selected from a second set of uplink scrambling sequences specifically assignable to individual user terminals.

First claim

The invention claimed is:

1. A method implemented in a user terminal for accessing a radio channel, the method comprises:
transmitting a random access preamble using a random access channel radio resource;
receiving a random access response message from the radio base station, wherein the random access response message indicates an identified radio resource and a temporary user terminal identifier indicating a scrambling sequence that is not specifically assigned to a user terminal;
determining an uplink scrambling sequence based on the temporary user terminal identifier included in the random access response message;
transmitting a message 3 to the radio base station, wherein the message 3 includes a user terminal identity that is different from the temporary user terminal identifier, and wherein the message 3 is transmitted over the identified radio resource, and wherein the message 3 is scrambled using the determined uplink scrambling sequence;
receiving a contention-resolution message from the radio base station, which includes the user terminal identity; and
transmitting a subsequent data transmission in the uplink scrambled with an uplink scrambling sequence based on the user terminal identity in the received contention-resolution message.

2. The method according to claim 1 , wherein the user terminal communicates with a long term evolution radio communications network, and wherein the random access preamble is transmitted over a random access channel and wherein the message 3 is transmitted over an uplink-shared channel.

3. The method according to claim 1 , wherein the random access response message further indicates a timing change and wherein the method further comprises:
adjusting a timing at the user terminal for transmitting signals to the radio base station based on the timing change received in the random access response message; and
wherein the message 3 is transmitted based on the adjusted timing.

4. The method according to Claim 1 , wherein the temporary user terminal identifier is a Temporary Cell Radio Network Temporary identifier.

5. The method according to claim 1 , wherein the user terminal identity is a Cell Radio Network Temporary Identifier.

6. The method according to claim 1 , wherein determining an uplink scrambling sequence based on the temporary user terminal identifier included in the random access response message comprises:
establishing a one-to-one mapping between the temporary user terminal identifier and the uplink scrambling sequence.

7. A method implemented in a base station associated with a cell for responding to user terminals requesting service from the base station over a radio channel, the method comprising:
receiving a random access preamble over a random access channel radio resource;
transmitting a random access response message to the user terminal, wherein the random access response message indicates an identified radio resource and a temporary user terminal identifier, wherein the temporary user terminal identifier indicates an uplink scrambling sequence that is not specifically assigned to the user terminal;
receiving over the identified radio resource a message 3 from the user terminal including a user terminal identity that is different from the temporary user terminal identifier, wherein the message 3 is scrambled with an uplink scrambling sequence as indicated in the random access response message;
transmitting a contention-resolution message to the user terminal which includes the user terminal identity; and
receiving a subsequent data transmission from the user terminal scrambled with an uplink scrambling sequence based on the user terminal identity in the transmitted contention-resolution message.

8. The method according to claim 7 , wherein the base station is part of a long term evolution radio communications network, and wherein the random access preamble is received over a random access channel and wherein the message 3 is received over an uplink-shared channel.

9. The method according to claim 7 , wherein the random access response message further indicates a timing change.

10. The method according to claim 7 , wherein the temporary user terminal identifier is a temporary Cell Radio Network Temporary Identifier.

11. The method according to claim 7 , wherein the user terminal identity is a Cell Radio Network Temporary Identifier.

12. A user terminal for requesting service from a base station having a cell area where the base station offers radio communications service, the user terminal comprising:
a radio transmitter configured to transmit a random access preamble using a random access channel radio resource;
a radio receiver configured to receive a random access response message from the radio base station, wherein the random access response message indicates an identified radio resource and a temporary user terminal identifier indicating a scrambling sequence that is not specifically assigned to a user terminal;
processing circuitry configured to determine an uplink scrambling sequence based on the temporary user terminal identifier included in the random access response message;
wherein the radio transmitter is configured to transmit a message 3 to the radio base station, wherein the message 3 includes a user terminal identity that is different from the temporary user terminal identifier, the message 3 is transmitted over the identified radio resource, and the message 3 is scrambled using the determined uplink scrambling sequence;
wherein the radio receiver is configured to receive a contention-resolution message from the radio base station, which includes the user terminal identity; and
wherein the radio transmitter is configured to transmit a subsequent data transmission in the uplink scrambled with an uplink scrambling sequence based on the user terminal identity in the received contention-resolution message.

13. The user terminal according to claim 12 , wherein the user terminal is configured to communicate with a long term evolution radio communications network, and
wherein the radio transmitter is configured to transmit the random access preamble over a random access channel and the message 3 over an uplink shared channel.

14. The user terminal according to claim 12 , wherein the random access response message further indicates a timing change, and wherein the processing circuitry is configured to adjust a timing at the user terminal for transmitting signals to the radio base station based on the timing change received in the random access response message, and wherein the radio transmitter is configured to transmit the message 3 based on the adjusted timing.

15. The user terminal according to claim 12 , wherein the temporary user terminal identifier is a Temporary Cell Radio Network Temporary Identifier.

16. The user terminal according to claim 12 , wherein the user terminal identity is a Cell Radio Network Temporary Identifier.

17. The user terminal according to claim 12 , wherein the processing circuitry is configured to determine the uplink scrambling sequence by establishing a one-to-one mapping between the temporary user terminal identifier and the uplink scrambling sequence.

18. The user terminal according to claim 12 , wherein the user terminal is configured to be assigned the user terminal identity prior to the transmission of the random access preamble.

19. The user terminal according to claim 12 , wherein the radio transmitter is configured to transmit the message 3 over an uplink-shared channel.

Assignees

• Ericsson Telefon Ab L M

Inventors

• Parkvall Stefan
• Dahlman Erik
• Tynderfeldt Tobias

Classifications

• H04W72/21 Primary

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

• H04W72/02 Primary

  Selection of wireless resources by user or terminal · CPC title

• H04W74/004

  in the uplink, i.e. towards network · CPC title

• H04W72/0413 Primary

  Electricity · mapped topic

• H04W74/0833 Primary

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