Uplink scrambling during random access

• US 9,949,239 B2
• Filed: 04/03/2014
• Issued: 04/17/2018
• Est. Priority Date: 08/08/2007
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Parkvall, Stefan, Dahlman, Erik, Tynderfeldt, Tobias
• Primary Examiner(s): Gidado, Rasheed
• Application Number:
  US14/244,580
• Publication Number:
  US 20140219257A1
• Time in Patent Office: 1,475 Days
• Field of Search: 370336, 370329
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• 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 74/0833 Random access procedures, e.g. with 4-step access

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.

Claims

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.

20. The user terminal according to claim 19, wherein the user terminal is configured to apply to message 3 a cyclic redundancy check, coding, a hybrid-Automatic Repeat Request, or a Discrete Fourier Transform Spread Orthogonal frequency-division multiplexing modulation.

21. The user terminal according to claim 19, wherein the user terminal is configured to apply to message 3 a cyclic redundancy check, coding, a hybrid-Automatic Repeat Request, and a Discrete Fourier Transform Spread Orthogonal frequency-division multiplexing modulation.

22. The user terminal according to claim 12, wherein the radio receiver is configured to receive a random access response message over a downlink-shared channel.

23. The user terminal according to claim 12, wherein the radio receiver is further configured to receive over a broadcast channel an indication of a set of random access preambles.

24. The user terminal according to claim 23, wherein the processing circuitry is further configured to select the random access preamble from the set of random access preambles.

25. The user terminal according to claim 24, wherein the processing circuitry is configured to select the random access preamble from the set of random access preambles randomly.

26. The user terminal according to claim 25, wherein the radio transmitter is configured to transmit the random access preamble in a random access request message and to a radio base station.

27. A radio base station configured to be associated with a cell for responding to user terminals requesting service from the base station over a radio channel, comprising circuitry configured to:

receive a random access preamble over a random access channel radio resource;

transmit 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, and wherein the temporary user terminal identifier indicates an uplink scrambling sequence that is not specifically assigned to the user terminal;

receive from the user terminal over the identified radio resource a message 3 scrambled with the uplink scrambling sequence, wherein the message 3 includes a user terminal identity that is different from the temporary user terminal identifier;

transmit a contention-resolution. message to the user terminal, which includes the user terminal identity; and

receive 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.

28. The radio base station according to claim 27, wherein the base station is part of a long term evolution radio communications network, and wherein the circuitry is configured to receive the random access preamble over a random access channel and the message 3 over an uplink shared channel.

29. The radio base station according to claim 27, wherein the random access response message further indicates a timing change.

30. The radio base station according to claim 27, wherein the temporary user terminal identifier is a Temporary Cell Radio Network Temporary Identifier.

31. The radio base station according to claim 27, wherein the user terminal identity is a Cell Radio Network Temporary Identifier.