Method and apparatus for transmitting/receiving preamble of random access channel in a broadband wireless communication system

• US 9,014,103 B2
• Filed: 08/21/2007
• Issued: 04/21/2015
• Est. Priority Date: 08/21/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Moon, Hi-Chan, Hong, Seung-Chul
• Primary Examiner(s): PARK, JUNG H
• Application Number:
  US11/842,833
• Publication Number:
  US 20080043671A1
• Time in Patent Office: 2,800 Days
• Field of Search: 370/328, 370/329, 370/330, 370/335, 370/336, 370/342, 370/345, 375/343, 415/450, 415/512
• US Class Current: 370/329
• 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
• CPC Class Codes: H04W 74/0866 using a dedicated channel for access

Abstract

A method for transmitting a preamble over a Random Access CHannel (RACH) in a wireless communication system is provided. The method includes generating a preamble having a length longer than a basic transmission unit, and dividing the preamble into preambles having a length less than the basic transmission unit; and sequentially transmitting the divided preambles over the RACH using different antennas.

Claims

1. A method for transmitting a preamble over a Random Access CHannel (RACH) in a wireless communication system, the method comprising:

generating one preamble having a length greater than a length of a sub-frame, and dividing the one preamble into preambles, each of the preambles having a length less than the length of the sub-frame;

setting different guard times, during which no preamble is transmitted, between the divided preambles; and

sequentially transmitting the divided preambles over the RACH using different antennas,

wherein each guard time is longer than a round-trip delay time of the sub-frame.

2. The method of claim 1, wherein each guard time is determined depending on a system parameter received from a base station.

3. The method of claim 1, wherein the length of the one preamble is determined depending on a system parameter received from a base station.

4. The method of claim 3, wherein the length of the one preamble is set in proportion to a cell size of the base station.

5. The method of claim 1, wherein the divided preambles are equal in length to each other.

6. The method of claim 1, wherein the divided preambles are different in length from each other.

7. The method of claim 1, wherein the one preamble further comprises an IDentifier (ID) of a mobile terminal.

8. A method for receiving a preamble over a Random Access CHannel (RACH) in a wireless communication system, the method comprising:

receiving samples of preambles divided and transmitted for basic transmission units of the RACH, and storing the received samples in a memory;

comparing a size of a correlation value determined by performing synchronous and asynchronous accumulation on the stored samples, with a predetermined threshold; and

if the correlation value is greater than the threshold, determining that the preamble is received,

wherein the comparing comprises;

independently performing synchronous accumulation on the samples of the preambles for the individual basic transmission units; and

independently squaring the synchronous-accumulated result values, converting the squared values into energy values, and accumulating the energy values.

9. An apparatus for transmitting a preamble over a Random Access CHannel (RACH) in a wireless communication system, the apparatus comprising:

a signature generator for generating one preamble longer than a sub-frame, setting, as a guard time, a time longer than a round-trip delay time of the sub-frame, and generating a signature of the one preamble,

wherein the signature generator divides a sequence of the one preamble into at least two preambles, and sets different guard times, during which no preamble is transmitted, between the at least two divided preambles; and

a modulator for amplifying the signature of the one preamble, performing an Radio Frequency (RF) modulation thereon, and outputting a radio signal.

10. The apparatus of claim 9, wherein multiple modulators are provided to perform an RF modulation on the divided preambles, and the divided preambles are transmitted via multiple antennas.

11. The apparatus of claim 9, further comprising:

at least two antennas for transmitting the divided preambles; and

a switch for switching the divided preambles to one of the antennas.

12. An apparatus for receiving a preamble over a Random Access CHannel (RACH) in a wireless communication system, the apparatus comprising:

a memory for receiving samples of preambles divided and transmitted for basic transmission units of the RACH, and storing the received samples for a slot interval;

a searcher for generating a correlation value determined by performing synchronous and asynchronous accumulation on the stored samples;

a decider for comparing a size of the correlation value with a predetermined threshold, and if the correlation value is greater than the threshold, determining that the preamble is received; and

a controller for controlling a length of the synchronous and asynchronous accumulation,

wherein the decider independently performs synchronous accumulation on the samples of the preambles for the individual basic transmission units, independently squares the synchronous-accumulated result values, converts the squared values into energy values, and accumulates the energy values.

13. A method for determining a preamble of a Random Access CHannel (RACH) and providing the preamble to a mobile terminal in a wireless communication system, the method comprising:

determining a length of the preamble such that the preamble has a length longer than a basic transmission unit, and determining a guard time taking into account a signal coverage of a base station;

providing information on the length and guard time of the preamble to the mobile terminal; and

determining a size in which the preamble is to be divided for a transmission of the divided preambles via at least two antennas, determining a guard time between the divided preambles, and providing the preamble to the mobile terminal.