RANDOM ACCESS METHOD AND APPARATUS FOR USE IN WIRELESS COMMUNICATION SYSTEM SUPPORTING DUAL CONNECTIVITY

• US 20150271768A1
• Filed: 03/18/2015
• Published: 09/24/2015
• Est. Priority Date: 03/21/2014
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: JANG, Jaehyuk, KIM, Soenghun, VAN LIESHOUT, Gert-Jan, KIM, Youngbum
• Granted Patent: US 9,854,619 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/244 Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]
• CPC Class Codes: H04W 52/30 using constraints in the total amount of available transmission power
• CPC Class Codes: H04W 52/34 TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/365 Power headroom reporting
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff
• CPC Class Codes: H04W 52/48 during retransmission after error or non-acknowledgment
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 76/15 Setup of multiple wireless link connections

Abstract

A random access method and an apparatus of a terminal for performing random access procedure to multiple base stations in parallel in a Long Term Evolution (LTE) system supporting dual connectivity are provided. The method includes determining whether a first preamble transmission to a first cell of a first base station is overlapped with a second preamble transmission to a second cell of a second base station in a time domain, determining, when the first preamble transmission is overlapped with the second preamble transmission in the time domain, whether a sum of transmit powers calculated for the first and second preamble transmissions is greater than a maximum allowed transmit power of the terminal, and controlling, when the sum of the first and second preamble transmit powers is greater than the maximum allowed transmit power, the transmit power calculated for the second preamble transmission.

Claims

1. A communication method of a terminal capable of communicating with two base stations in parallel, the method comprising:

determining whether a first preamble transmission to a first cell of a first base station is overlapped with a second preamble transmission to a second cell of a second base station in a time domain;

determining, when the first preamble transmission is overlapped with the second preamble transmission in the time domain, whether a sum of transmit powers calculated for the first and second preamble transmissions is greater than a maximum allowed transmit power of the terminal; and

controlling, when the sum of the first and second preamble transmit powers is greater than the maximum allowed transmit power, the transmit power calculated for the second preamble transmission.

2. The method of claim 1, wherein the first base station comprises a master base station, and the second base station comprises a slave base station.

3. The method of claim 1, wherein the first cell comprises a Primary cell (PCell), and the second cell comprises one of a primary Secondary cell (pSCell) and a Secondary cell (SCell).

4. The method of claim 1, further comprising maintaining, when the sum of the transmit powers is greater than the maximum allowed transmit power, the transmit power calculated for the first preamble transmission.

5. The method of claim 1, wherein the controlling of the transmit powers comprises dropping, when the sum of the transmit powers calculated for the first and second preamble transmissions is greater than the maximum allowed transmit power of the terminal, the second preamble transmission.

6. The method of claim 5, further comprising:

retransmitting, when at least one of the first and second preamble transmissions is dropped, the transmission-failed preamble at the preamble transmit power calculated based on a number of retransmissions.

7. The method of claim 6, further comprising skipping, when the second preamble transmission is dropped, an increase of the number of retransmissions of the second preamble.

8. The method of claim 1, wherein the controlling of the transmit powers comprises adjusting, when the sum of the first and second preamble transmit powers is greater than the maximum allowed transmit power, the transmit power calculated for the second preamble transmission.

9. The method of claim 8, wherein the controlling of the transmit powers comprises adjusting the transmit power of the second preamble to maintain the sum of the first and second preamble transmit powers below the maximum allowed transmit power.

10. The method of claim 8, further comprising retransmitting, when at least one of the first and second preamble transmissions is dropped, the transmission-failed preamble at the preamble transmit power calculated based on a number of retransmissions.

11. The method of claim 10, further comprising skipping, when the transmit power calculated for the second preamble transmission is adjusted, an increase of the number of retransmissions of the second preamble.

12. A terminal capable of communicating with two base stations in parallel, the terminal comprising:

a transceiver configured to transmit and receive signals to and from a first and a second base stations; and

a controller configured;

to determine whether a first preamble transmission to a first cell of a first base station is overlapped with a second preamble transmission to a second cell of a second base station in a time domain,

to determine, when the first preamble transmission is overlapped with the second preamble transmission in the time domain, whether a sum of transmit powers calculated for the first and second preamble transmissions is greater than a maximum allowed transmit power of the terminal, and

to control, when the sum of the first and second preamble transmit powers is greater than the maximum allowed transmit power, the transmit power calculated for the second preamble transmission.

13. The terminal of claim 12, wherein the first base station comprises a master base station, and the second base station comprises a slave base station.

14. The terminal of claim 13, wherein the first cell is a Primary cell (PCell), and the second cell is one of a primary Secondary cell (pSCell) and a Secondary cell (SCell).

15. The terminal of claim 12, wherein the controller is further configured to control maintaining, when the sum of the transmit powers is greater than the maximum allowed transmit power, the transmit power calculated for the first preamble transmission.

16. The terminal of claim 12, wherein the controller is further configured to control dropping, when the sum of the transmit powers calculated for the first and second preamble transmissions is greater than the maximum allowed transmit power of the terminal, the second preamble transmission.

17. The terminal of claim 16, wherein the controller is further configured to control retransmitting, when at least one of the first and second preamble transmissions is dropped, the transmission-failed preamble at the preamble transmit power calculated based on a number of retransmissions.

18. The terminal of claim 17, wherein the controller is further configured to control skipping, when the second preamble transmission is dropped, an increase of the number of retransmissions of the second preamble.

19. The terminal of claim 12, wherein the controller is further configured to adjust, when the sum of the first and second preamble transmit powers is greater than the maximum allowed transmit power, the transmit power calculated for the second preamble transmission.

20. The terminal of claim 19, wherein the controller is further configured to adjust the transmit power of the second preamble to maintain the sum of the first and second preamble transmit powers below the maximum allowed transmit power.

21. The terminal of claim 19, wherein the controller is further configured to control retransmitting, when at least one of the first and second preamble transmissions is dropped, the transmission-failed preamble at the preamble transmit power calculated based on a number of retransmissions.

22. The terminal of claim 21, wherein the controller is further configured to control skipping, when the transmit power calculated for the second preamble transmission is adjusted, an increase of the number of retransmissions of the second preamble.