Random access method and apparatus for use in wireless communication system supporting dual connectivity

• US 9,854,619 B2
• Filed: 03/18/2015
• Issued: 12/26/2017
• 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
• Primary Examiner(s): Wong, Warner
• Application Number:
  US14/661,459
• Publication Number:
  US 20150271768A1
• Time in Patent Office: 1,014 Days
• 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 method by a terminal communicating with two base stations, the method comprising:

identifying that a transmission of a first preamble on a primary cell (PCell) of a first base station is overlapped with a transmission of a second preamble on a secondary cell (SCell) of a second base station in a time domain and a sum of transmission powers determined for the first and the second preambles exceeds a maximum allowed transmission power of the terminal;

transmitting the first preamble on the PCell based on the transmission power determined for the first preamble;

controlling the transmission of the second preamble on the SCell such that the sum of the transmission powers determined for the first and the second preambles does not exceed the maximum allowed transmission power of the terminal; and

skipping an increase of a number of transmissions of the second preamble, the number of transmissions of the second preamble being used to determine the transmission power for the second preamble.

2. The method of claim 1,

wherein the first base station comprises a master base station, and

wherein the second base station comprises a secondary base station.

3. The method of claim 1,

wherein the SCell comprises a primary secondary cell (pSCell).

4. The method of claim 1, wherein the controlling of the transmission of the second preamble comprises dropping the transmission of the second preamble on the SCell.

5. The method of claim 1, wherein the controlling of the transmission of the second preamble comprises:

adjusting the transmission power determined for the transmission of the second preamble to maintain the sum of the transmission powers below the maximum allowed transmission power; and

transmitting the second preamble on the SCell based on the adjusted transmission power.

6. The method of claim 5, wherein the increase of the number of transmissions of the second preamble is skipped if no random access response is received within a predetermined period.

7. The method of claim 6, further comprising retransmitting the second preamble at a transmission power determined based on the number of transmissions of the second preamble.

8. A terminal communicating with two base stations, 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;

identify that a transmission of a first preamble to a primary cell (PCell) of the first base station is overlapped with a transmission of a second preamble to a secondary cell (SCell) of the second base station in a time domain and a sum of transmission powers determined for the first and the second preambles exceeds a maximum allowed transmission power of the terminal,

control the transceiver to transmit the first preamble on the PCell based on the transmission power determined for the first preamble,

control the transmission of the second preamble on the SCell such that the sum of the transmission powers determined for the first and the second preambles does not exceed the maximum allowed transmission power of the terminal, and

skip an increase of a number of transmissions of the second preamble, the number of transmissions of the second preamble being used to determine the transmission power for the second preamble.

9. The terminal of claim 8,

wherein the first base station comprises a master base station, and

wherein the second base station comprises a secondary base station.

10. The terminal of claim 9,

wherein the SCell comprises a primary secondary cell (pSCell).

11. The terminal of claim 8, wherein the controller is further configured to control dropping the transmission of the second preamble on the SCell.

12. The terminal of claim 8, wherein the controller is further configured to:

adjust the transmission power determined for the second preamble to maintain the sum of the transmission powers below the maximum allowed transmission power, and

control the transceiver to transmit the second preamble on the SCell based on the adjusted transmission power.

13. The terminal of claim 12, wherein the increase of the number of transmissions of the second preamble is skipped if no random access response is received within a predetermined period.

14. The terminal of claim 13, wherein the controller is further configured to control the transceiver to retransmit the second preamble at a transmission power determined based on the number of transmissions of the second preamble.