METHOD AND APPARATUS FOR TRANSMITTING/RECEIVING PREAMBLE OF RANDOM ACCESS CHANNEL IN A BROADBAND WIRELESS COMMUNICATION SYSTEM

• US 20080043671A1
• Filed: 08/21/2007
• Published: 02/21/2008
• Est. Priority Date: 08/21/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Hong, Seung-Chul, MOON, Hi-Chan
• Granted Patent: US 9,014,103 B2
• Time in Patent Office: Days
• 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 a preamble having a length greater than a length of a basic transmission unit, and dividing the preamble into preambles having a length less than the length of a basic transmission unit; and

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

2. The method of claim 1, further comprising:

defining a guard time between the divided preambles during the transmission of the divided preambles.

3. The method of claim 2, wherein the guard time is longer than a round-trip delay time of the basic transmission unit.

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

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

6. The method of claim 5, wherein the length of the preamble is set in proportion to a cell size of the base station.

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

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

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

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

receiving a sample of the RACH received for at least two basic transmission units, and storing the received sample 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.

11. The method of claim 10, 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.

12. 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 a preamble longer than a basic transmission unit, setting, as a guard time, a time longer than a round-trip delay time of a sub-frame, and generating a signature of the preamble; and

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

13. The apparatus of claim 12, wherein the signature generator divides a sequence of the preamble into at least two preambles.

14. The apparatus of claim 13, wherein the signature generator sets different guard times, during which no preamble is transmitted, between the at least two divided preambles.

15. The apparatus of claim 13, wherein multiple modulators are provided to perform an RF modulation on the divided preambles, and the divided preambles are transmitted via multiple antennas.

16. The apparatus of claim 13, further comprising:

at least two antennas for transmitting the divided preambles; and

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

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

a memory for receiving a sample of the RACH received for at least two basic transmission units, and storing the received sample 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.

18. The apparatus of claim 17, 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.

19. 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; and

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

20. The method of claim 19, further comprising:

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.