UPLINK SYNCHRONIZATION REQUEST METHOD IN MOBILE COMMUNICATION SYSTEM, CDMA ALLOCATION IE THEREOF, AND APPARATUS USING THE SAME

• US 20090190560A1
• Filed: 03/20/2007
• Published: 07/30/2009
• Est. Priority Date: 06/14/2006
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Ahn, Jee-Hwan, Yoon, Chul-Sik, Lim, Kwang-Jae, Kim, Sung-Kyung
• Granted Patent: US 8,503,404 B2
• Time in Patent Office: Days
• US Class Current: 370/335
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 56/0075 based on arrival time vs. expected arrival time

Abstract

The present invention relates to an uplink synchronization request method in a mobile communication system, a CDMA allocation information element structure thereof, and an apparatus using the same. For this purpose the uplink synchronization request method includes: when up-link traffic is generated, determining whether an uplink synchronization error occurs; when the uplink synchronization error occurs, calculating a timing adjustment value; and transmitting a bandwidth request code including the calculated timing adjustment value to a base station and performing a band-width request. According to the present invention, the PSS compares a reference adjustment value and an arrival time of a downlink preamble to calculate uplink synchronization timing and synchronize an uplink of the PSS that requests bandwidth allocation through a bandwidth request ranging process to thereby maximize resource use efficiency in the uplink synchronization.

Claims

1. A method for requesting uplink synchronization in a mobile communication system, the method comprising:

determining whether an uplink synchronization error occurs if uplink traffic is generated;

calculating a timing adjustment value if the uplink synchronization error occurs; and

transmitting a bandwidth request code including the calculated timing adjustment value to a base station to request a bandwidth.

2. The method of claim 1, wherein the method further comprises performing initial ranging with the base station and storing an initial timing value.

3. The method of claim 2, wherein the initial timing value corresponds to a reference adjustment value of a data frame for the base station to perform initial ranging with a plurality of portable subscriber stations (PSSs).

4. The method of claim 3, wherein when a time gap between an uplink arrival time of the n-th data frame and an arrival time of a downlink preamble of the (n+1)-th frame is set to a “

time gap before movement”

before the PSS moves and a time gap between an uplink arrival of the n-th data frame and an arrival time of a downlink preamble of the (n+1)-th frame is set to a “

time gap after movement”

after the PSS moves, a difference between the time gap before movement and the time gap after movement corresponds to the timing adjustment value (where n is a natural number).

5. The method of claim 1, wherein the method further comprises:

receiving a code division multiplex access (CDMA) allocation information element (CDMA_Allocation_IE) from the base station;

correcting uplink synchronization by using transmission parameter values include in the received CDMA allocation information element; and

transmitting data to the base station by using a bandwidth allocated from the base station through the received CDMA allocation information element.

6. The method of claim 5, wherein the CDMA allocation information element including:

a transmission opportunity including information on an interval of time when a particular PSS has the right to initiate data transmission through an uplink;

a timing adjustment including information on a timing adjustment value included in the bandwidth request code transmitted to the base station from the PSS for uplink synchronization; and

a power adjustment including information on transmit power among the transmission parameters adjusted by the PSS.

7. The method of claim 6, wherein correcting the uplink synchronization comprises correcting the uplink synchronization by using predetermined values of the transmission opportunity and the timing adjustment as the transmission parameter values.

8. The method of claim 6, wherein the CDMA allocation further includes:

a duration for indicating the number of slots allocated to the PSS;

an uplink interval usage (UIUC) for indicating a code used in the uplink;

a repetition code indication for indicating a repetition code used for the uplink traffic;

a frame number index for indicating the number of frames to be used for transmission of the uplink traffic;

a ranging code for indicating a code, a symbol, and a sub-channel for the ranging; and

a bandwidth (BW) request mandatory for indicating an identifier for the bandwidth request.

9. The method of claim 8, wherein receiving the CDMA allocation information element comprises receiving the CDMA allocation information element where the BW request mandatory included in the CDMA allocation information element is set to “

0”

.

10. The method of claim 5, wherein the method further comprises requesting an additional uplink bandwidth by transmitting a Grant_Management_Subheader message to the base station when the bandwidth allocated from the base station is insufficient.

11. A code division multiplex access (CDMA) allocation information element (CDMA_Allocation_IE) structure of an uplink MAP transmitted to a portable subscriber station (PSS) from a base station for uplink synchronization in a mobile communication system, the CDMA allocation information element structure comprising:

a transmission opportunity including information on an interval of time when a particular PSS has the right to initiate data transmission through an uplink;

a timing adjustment including information on a timing adjustment value included in the bandwidth request code transmitted to the base station from the PSS for uplink synchronization; and

a power adjustment including information on transmit power among the transmission parameters adjusted by the PSS.

12. The CDMA allocation information element structure of claim 11, further comprising:

a duration for indicating the number of slots allocated to the PSS;

an uplink interval usage (UIUC) for indicating a code used in the uplink;

a repetition code indication for indicating a repetition code used for the uplink traffic;

a frame number index for indicating the number of frames to be used for transmission of the uplink traffic;

a ranging code for indicating a code, a symbol, and a sub-channel for the ranging; and

a bandwidth (BW) request mandatory for indicating an identifier for the bandwidth request.

13. A portable subscriber station (PSS) that performs uplink synchronization through a ranging process using a bandwidth request code in a mobile communication system, the PSS comprising:

means for performing initial ranging with a base station and storing an initial timing value;

means for determining whether uplink traffic is generated;

means for determining whether an uplink synchronization error occurs when the uplink traffic is generated;

means for calculating a timing adjustment value when the uplink synchronization error occurs; and

means for transmitting a bandwidth request code including the calculated timing adjustment value to the base station and performing a bandwidth request.

14. The PSS of claim 13, further comprising:

means for receiving a code division multiplex access (CDMA) allocation information element (CDMA_Allocation_IE) from the base station;

means for correcting uplink synchronization by using transmission parameter values included in the received CDMA allocation information element; and

transmitting data to the base station by using a bandwidth allocated from the base station through the received CDMA allocation information element.

15. The PSS of claim 14, wherein the CDMA allocation information element comprises:

a transmission opportunity including information on an interval of time when a particular PSS has the right to initiate data transmission through an uplink;

a timing adjustment including information on a timing adjustment value included in the bandwidth request code transmitted to the base station from the PSS for uplink synchronization; and

a power adjustment including information on transmit power among the transmission parameters adjusted by the PSS.