Preamble sequence sending method and apparatus

• US 10,420,032 B2
• Filed: 06/29/2017
• Issued: 09/17/2019
• Est. Priority Date: 01/30/2015
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Hu, Wenquan, Hua, Meng
• Primary Examiner(s): Masur, Paul H
• Application Number:
  US15/637,505
• Publication Number:
  US 20170303204A1
• Time in Patent Office: 810 Days
• CPC Class Codes: H04W 52/06 TPC algorithms
• CPC Class Codes: H04W 52/10 Open loop power control
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/242 taking into account path loss
• CPC Class Codes: H04W 52/28 using user profile, e.g. mobile speed, priority or network state, e.g. standby, idle or non transmission
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/38 TPC being performed in particular situations
• 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

Abstract

A preamble sequence sending method and apparatus are provided. The method includes sending, by user equipment (UE), a first preamble sequence according to a first transmit power and using a repetition factor N₁; if the UE fails to receive, in a preset time period after the first preamble sequence is sent, a response message that is sent by a network-side device and that is corresponding to the first preamble sequence, switching, by the UE, to a next repetition factor N₂, where a quantity of consecutive sending times indicated by the next repetition factor N₂ is greater than a quantity of consecutive sending times indicated by the repetition factor N₁; and sending, by the UE, a second preamble sequence according to a second transmit power and using the next repetition factor N₂.

Claims

1. A preamble sequence sending method, comprising:

sending, by user equipment (UE), a first preamble sequence according to a first transmit power and using a repetition factor N₁;

switching, by the UE, to a next repetition factor N₂ when the UE fails to receive, in a preset time period after the first preamble sequence is sent, a response message from a network-side device and corresponding to the first preamble sequence, wherein a quantity of consecutive sending times indicated by the next repetition factor N₂ is greater than a quantity of consecutive sending times indicated by the repetition factor N₁;

determining, by the UE, a second transmit power using the following formula;

P_PRACH1=min{P_MAX,PREAMBLE_RECEIVED_TARGET_POWER1+PL},

wherein PREAMBLE_RECEIVED_TARGET_POWER1=preambleInitialReceivedTargetPower+DELTA_PREAMBLE+(PREAMBLE_TRANSMISSION_COUNTER−

1)*(powerRampingStep)+delta(N_l+1),

wherein P_PRACH1 is the second transmit power, min{ } is a MIN operation,

wherein P_MAX is a maximum permissible transmit power of the UE,

wherein PREAMBLE_RECEIVED_TARGET_POWER1 is a target preamble received power corresponding to a second preamble sequence,

wherein PL is an estimation value obtained by the UE by estimating a downlink path loss of a cell in which the UE is located,

wherein preambleInitialReceivedTargetPower is an initial target preamble received power,

wherein DELTA_PREAMBLE is a preamble sequence format offset value,

wherein PREAMBLE_TRANSMISSION_COUNTER is a preamble transmission counter,

wherein powerRampingStep is a power adjustment step, N_l+1 is the next repetition factor N₂, and

wherein delta (N_l+1) is a decreasing function of the next repetition factor N₂; and

sending, by the UE, the second preamble sequence according to the second transmit power and using the next repetition factor N₂.

2. The method according to claim 1, wherein switching, by the UE, to the next repetition factor N₂ comprises:

determining, by the UE, a third transmit power, wherein the third transmit power is greater than the first transmit power; and

switching to the next repetition factor N₂ when the third transmit power exceeds the maximum permissible transmit power of the UE.

3. The method according to claim 1, wherein when the first preamble sequence is the first preamble sequence in a random access procedure, the method further comprises:

obtaining, by the UE, a target preamble received power corresponding to the first preamble sequence;

obtaining, by the UE, an offset constant offset (N₁) corresponding to the repetition factor N₁; and

determining, by the UE, the first transmit power according to the maximum permissible transmit power of the UE, the target preamble received power corresponding to the first preamble sequence, the offset constant offset (N₁) corresponding to the repetition factor N₁, and an estimation value obtained by the UE by estimating the downlink path loss of the cell in which the UE is located.

4. The method according to claim 1, wherein before sending, by the UE, the first preamble sequence according to the first transmit power and using the repetition factor N₁, the method further comprises obtaining, by the UE, a group of sending information corresponding to the repetition factor N₁, wherein the sending information comprises a preamble index and a physical random access channel (PRACH) resource, and wherein sending, by the UE, the first preamble sequence according to the first transmit power and using the repetition factor N₁ comprises sending, by the UE and on the PRACH resource, according to the first transmit power and using the repetition factor N₁, the first preamble sequence corresponding to the preamble index.

5. The method according to claim 1, wherein when the repetition factor N₁ is an initial repetition factor, before sending, by the UE, the first preamble sequence according to the first transmit power and using the repetition factor N₁, the method further comprises:

determining, by the UE, preamble sequence powers separately corresponding to a first repetition factor and a second repetition factor;

determining that the first repetition factor is the repetition factor N₁ when a preamble sequence power corresponding to the first repetition factor is less than or equal to a difference between the maximum permissible transmit power of the UE and a specific constant and a preamble sequence power corresponding to the second repetition factor is greater than the difference between the maximum permissible transmit power of the UE and the specific constant; and

determining that the first repetition factor is the repetition factor N₁ when a preamble sequence power corresponding to the first repetition factor is less than a difference between the maximum permissible transmit power of the UE and a specific constant and a preamble sequence power corresponding to the second repetition factor is greater than or equal to the difference between the maximum permissible transmit power of the UE and the specific constant, wherein the second repetition factor is less than the first repetition factor and is adjacent to the first repetition factor among repetition factors.

6. The method according to claim 1, wherein the repetition factor N₁ is corresponding to a first coverage enhancement level of the UE, wherein the next repetition factor N₂ is corresponding to a second coverage enhancement level of the UE, and wherein the second coverage enhancement level is higher than the first coverage enhancement level.

7. The method according to claim 1, wherein before switching, by the UE, to the next repetition factor N₂, the method comprises obtaining, by the UE, the next repetition factor N₂ by adding a repetition factor step to the repetition factor N₁, wherein the repetition factor N₁ is corresponding to a first coverage enhancement level of the UE, wherein the next repetition factor N₂ is corresponding to the first coverage enhancement level when the next repetition factor N₂ is less than or equal to a maximum repetition factor corresponding to the first coverage enhancement level, wherein the next repetition factor N₂ is corresponding to a second coverage enhancement level of the UE when the next repetition factor N₂ is greater than the maximum repetition factor, and wherein the second coverage enhancement level is higher than the first coverage enhancement level.

8. The method according to claim 1, wherein delta (N_l+1) is −

10 log (N_l+1).

9. A preamble sequence sending apparatus, comprising:

a memory configured to store software instructions; and

a processor coupled to the memory and configured to execute the software instructions to perform;

sending a first preamble sequence according to a first transmit power and using a repetition factor N₁;

switching to a next repetition factor N₂ when no response message from a network-side device and corresponding to the first preamble sequence is received in a preset time period after the first preamble sequence is sent, wherein a quantity of consecutive sending times indicated by the next repetition factor N₂ is greater than a quantity of consecutive sending times indicated by the repetition factor N₁;

determining a second transmit power using the following formula;

P_PRACH1=min{P_MAX,PREAMBLE_RECEIVED_TARGET_POWER1+PL}, wherein

PREAMBLE_RECEIVED_TARGET_POWER1=preambleInitialReceivedTargetPower+DELTA_PREAMBLE+(PREAMBLE_TRANSMISSION_COUNTER−

1)*(powerRampingStep)+delta(N_l+1),

wherein P_PRACH1 is the second transmit power, min{ } is a MIN operation,

wherein P_MAX is a maximum permissible transmit power of user equipment (UE),

wherein PREAMBLE_RECEIVED_TARGET_POWER1 is a target preamble received power corresponding to a second preamble sequence,

wherein PL is an estimation value obtained by the UE by estimating a downlink path loss of a cell in which the UE is located,

wherein preambleInitialReceivedTargetPower is an initial target preamble received power,

wherein DELTA_PREAMBLE is a preamble sequence format offset value,

wherein PREAMBLE_TRANSMISSION_COUNTER is a preamble transmission counter,

wherein powerRampingStep is a power adjustment step,

wherein N_l+1 is the next repetition factor N₂, and

wherein delta (N_l+1) is a decreasing function of the next repetition factor N₂; and

sending the second preamble sequence according to the second transmit power and using the next repetition factor N₂.

10. The apparatus according to claim 9, wherein the processor is further configured to perform:

determining a third transmit power, wherein the third transmit power is greater than the first transmit power; and

switching to the next repetition factor N₂ when the third transmit power exceeds the maximum permissible transmit power of the UE.

11. The apparatus according to claim 9, wherein the processor is further configured to perform:

obtaining a target preamble received power corresponding to the first preamble sequence when the first preamble sequence is the first preamble sequence in a random access procedure;

obtaining an offset constant offset (N₁) corresponding to the repetition factor N₁; and

determining the first transmit power according to the maximum permissible transmit power of the UE, the target preamble received power corresponding to the first preamble sequence, the offset constant offset (N₁) corresponding to the repetition factor N₁, and an estimation value obtained by estimating the downlink path loss of the cell in which the UE is located.

12. The apparatus according to claim 9, wherein before sending the first preamble sequence according to the first transmit power and using the repetition factor N₁, the processor is further configured to perform:

obtaining a group of sending information corresponding to the repetition factor N₁, wherein the sending information comprises a preamble index and a physical random access channel (PRACH) resource; and

sending, on the PRACH resource, according to the first transmit power and using the repetition factor N₁, the first preamble sequence corresponding to the preamble index.

13. The apparatus according to claim 9, wherein the processor is further configured to perform:

determining, before sending the first preamble sequence according to the first transmit power and using the repetition factor N₁, preamble sequence powers separately corresponding to a first repetition factor and a second repetition factor when the repetition factor N₁ is an initial repetition factor;

determining that the first repetition factor is the repetition factor N₁ when a preamble sequence power corresponding to the first repetition factor is less than or equal to a difference between the maximum permissible transmit power of the UE and a specific constant and a preamble sequence power corresponding to the second repetition factor is greater than the difference between the maximum permissible transmit power of the UE and the specific constant; and

determining that the first repetition factor is the repetition factor N₁ when a preamble sequence power corresponding to the first repetition factor is less than a difference between the maximum permissible transmit power of the UE and a specific constant and a preamble sequence power corresponding to the second repetition factor is greater than or equal to the difference between the maximum permissible transmit power of the UE and the specific constant, wherein the second repetition factor is less than the first repetition factor and is adjacent to the first repetition factor among repetition factors.

14. The apparatus according to claim 9, wherein the repetition factor N₁ is corresponding to a first coverage enhancement level of the UE, wherein the next repetition factor N₂ is corresponding to a second coverage enhancement level of the UE, and wherein the second coverage enhancement level is higher than the first coverage enhancement level.

15. The apparatus according to claim 9, wherein the processor is further configured to perform obtaining the next repetition factor N₂ by adding a repetition factor step to the repetition factor N₁, wherein the repetition factor N₁ is corresponding to a first coverage enhancement level of the UE, wherein the next repetition factor N₂ is corresponding to the first coverage enhancement level when the next repetition factor N₂ is less than or equal to a maximum repetition factor corresponding to the first coverage enhancement level, wherein the next repetition factor N₂ is corresponding to a second coverage enhancement level of the UE when the next repetition factor N₂ is greater than the maximum repetition factor, and wherein the second coverage enhancement level is higher than the first coverage enhancement level.

16. The apparatus according to claim 9, wherein delta (N_l+1) is −

10 log (N_l+1).