Method for synchronizing reverse link and transmission method using synchronous reverse link

• US 6,516,007 B1
• Filed: 05/10/1999
• Issued: 02/04/2003
• Est. Priority Date: 07/23/1998
• Status: Active Grant

• Current Assignee: SK Telecom Co., Ltd.
• Original Assignee: SK Telecom Co., Ltd.
• Inventors: Hong, Een Kee, Lee, Dong Do, Lee, Sang Yon, Koo, Jun Mo, Lee, Sung Jae
• Primary Examiner(s): Patel, Ajit
• Assistant Examiner(s): SHAH, CHIRAG G
• Application Number:
  US09/307,745
• Time in Patent Office: 1,366 Days
• Field of Search: 370/431, 370/441, 370/464, 370/508, 370/342, 370/343, 370/335, 370/320, 370/324, 370/328-330, 370/350, 455/502
• US Class Current: 370/515
• CPC Class Codes: H04B 7/2681 Synchronisation of a mobile station with one base station
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks

Abstract

A transmission method using synchronous reverse links establishes synchronization by controlling transmission times of mobile stations according to synchronization control messages received through a control channel and then controlling the transmission times according to synchronization control bits received through a traffic channel.

Claims

1. A method of establishing reverse channel synchronization, comprising the steps of:

a) transmitting, from a mobile station, a reverse access signal to a base station through a control channel;

b) receiving, at the base station, the reverse access signal, calculating the difference in time between a reference time and the receiving time of the reverse access signal, and, based on the calculated time difference, generating and transmitting a synchronization control message to the mobile station through a control channel; and

c) adjusting, at the mobile station, a reverse transmission time according to the synchronization control message, and transmitting a reverse link signal to the base station;

wherein the reference time is a median value between the maximum and the minimum round trip delays associated with a cell radius of the base station.

2. The method as claimed in claim 1, wherein the base station repeatedly performs steps b) and c) if the synchronization has not been established.

3. A transmission method using synchronous reverse channels in a wireless communication system, said method comprising the steps of:

a) transmitting, from a mobile station, a reverse access signal to a base station through a control channel;

b) receiving, at the base station, the reverse access signal, calculating the difference in time between a reference time and the receiving time of the reverse access signal, and, based on the calculated time difference, generating and transmitting a synchronization control message to the mobile station through the control channel;

c) adjusting, at the mobile station, a reverse transmission time according to the synchronization control message, and establishing reverse channel synchronization by transmitting a reverse link signal to the base station;

d) transmitting, from the base station, a traffic channel start command to the mobile station through a traffic channel;

e) transmitting, from the mobile station, data to the base station through the traffic channel;

f) periodically comparing, at the base station, the receiving time of the data with the reference time, and, based on the comparison, generating and transmitting a synchronization control bit to the mobile station through the traffic channel; and

g) controlling, at the mobile station, a subsequent transmission time according to the synchronization control bits;

wherein the reference time is a median value between the maximum and the minimum round trip delays associated with a cell radius of the base station.

4. The method as claimed in claim 3, wherein multiple channels connecting multiple said mobile stations, which are located in the cell or sector associated with said base station, to said base station share an identical pseudo noise code, and each of the channels in the sector or the cell is discriminated by an uniquely assigned orthogonal code and transmits a reverse signal.

5. The method as claimed in claim 3, wherein the step e) includes the steps of assigning another pseudo noise code, and generating and transmitting a reverse signal when all available orthogonal codes have already been assigned and more channels are necessary to be discriminated.

6. The method as claimed in claim 3, wherein the synchronization control bit is transmitted on the traffic channel instead of a power control bit.

7. The method as claimed in claim 3, wherein the reverse synchronization control bit is inserted before channel coding to enable the mobile station to accurately extract the synchronization control bit.

8. A transmission method using synchronous reverse channels in a wireless communication system, said method comprising the steps of:

a) transmitting, from a mobile station, a reverse access signal to a base station through a control channel;

b) receiving, at the base station, the reverse access signal, calculating the difference in time between a reference time and the receiving time of the reverse access signal, and, based on the calculated time difference, generating and transmitting a synchronization control message to the mobile station through the control channel;

c) adjusting, at the mobile station, a reverse transmission time according to the synchronization control message, and establishing reverse channel synchronization by transmitting a reverse link signal to the base station;

d) transmitting, from the base station, a traffic channel start command to the mobile station through a traffic channel;

e) transmitting, from the mobile station, data to the base station through the traffic channel;

f) periodically comparing, at the base station, the receiving time of the data with the reference time, and, based on the comparison, generating and transmitting a synchronization control bit to the mobile station through the traffic channel; and

g) controlling, at the mobile station, a subsequent transmission time according to the synchronization control bits;

wherein multiple channels connecting multiple said mobile stations, which are located in the cell or sector associated with said base station, to said base station share a common identical pseudo noise code, and each of the channels in the sector or the cell is discriminated by an uniquely assigned orthogonal code.

9. The method as claimed in claim 8, wherein another pseudo noise code is assigned to at least one of the channels when the number of channels in the cell or sector is larger than the number of available orthogonal codes and all of the available orthogonal codes have already been assigned.