Methods and apparatus for random access in multi-carrier communication systems

• US 10,390,369 B2
• Filed: 02/06/2017
• Issued: 08/20/2019
• Est. Priority Date: 03/09/2004
• Status: Active Grant

• Current Assignee: Neo Wireless LLC (f/k/a CFIP NCF LLC) (SoftBank Group Corp.)
• Original Assignee: Neocific Incorporated
• Inventors: Li, Xiaodong, Lo, Titus, Li, Kemin, Huang, Haiming
• Primary Examiner(s): Wei, Siren
• Application Number:
  US15/425,735
• Publication Number:
  US 20170374685A1
• Time in Patent Office: 925 Days
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

Methods and apparatus in a multi-carrier cellular wireless network with random access improve receiving reliability and reduce interference of uplink signals of a random access, while improving the detection performance of a base station receiver by employing specifically configured ranging signals.

Claims

1. A method for signal transmission by a mobile station in a cell in an orthogonal frequency division multiple access (OFDMA) cellular system, the method comprising:

transmitting a ranging signal containing a full ranging sequence in a ranging time slot containing multiple Orthogonal Frequency Division Multiplexing (OFDM) symbols, wherein;

the full ranging sequence is composed of multiple concatenated shorter sequence segments, each sequence segment of the full ranging sequence being carried on a block of contiguous subcarriers in an OFDM symbol in the multiple-OFDM-symbol ranging time slot; and

the full ranging sequence is segment-wise orthogonal to other full ranging sequences used in the cell containing the mobile station; and

transmitting data over a data subchannel.

2. The method of claim 1, wherein each sequence segment of the full ranging sequence is a Hadamard sequence.

3. The method of claim 1, wherein the full ranging sequence is a non-binary sequence.

4. The method of claim 1, wherein different cells have different blocks of subcarrier configurations.

5. The method of claim 1, wherein the number of multiple concatenated shorter sequence segments is four.

6. The method of claim 1, further comprising controlling a power level for the transmission of the full ranging sequence using an open-loop power control scheme.

7. A mobile station in a cell in an orthogonal frequency division multiple access (OFDMA) cellular system, the mobile station comprising a transmitter configured to transmit:

a ranging signal containing a full ranging sequence in a ranging time slot containing multiple Orthogonal Frequency Division Multiplexing (OFDM) symbols, wherein;

the full ranging sequence is composed of multiple concatenated shorter sequence segments, each sequence segment of the full ranging sequence being carried on a block of contiguous subcarriers in an OFDM symbol in the multiple-OFDM-symbol ranging time slot; and

the full ranging sequence is segment-wise orthogonal to other full ranging sequences used in the cell containing the mobile station; and

data over a data subchannel.

8. The mobile station of claim 7, wherein each sequence segment of the full ranging sequence is a Hadamard sequence.

9. The mobile station of claim 7, wherein the full ranging sequence is a non-binary sequence.

10. The mobile station of claim 7, wherein different cells have different blocks of subcarrier configurations.

11. The mobile station of claim 7, wherein the number of multiple concatenated shorter sequence segments is four.

12. The mobile station of claim 7, further comprising a controller configured to control a transmission power level of the full ranging sequence using an open-loop power control scheme.