Preamble transmission method and apparatus

• US 10,536,973 B2
• Filed: 08/05/2016
• Issued: 01/14/2020
• Est. Priority Date: 08/07/2015
• Status: Active Grant

• Current Assignee: ZTE Corporation
• Original Assignee: ZTE Corporation
• Inventors: Yang, Ling, Gou, Wei, Zhao, Yajun, Peng, Focai, Bi, Feng, Li, Xincai
• Primary Examiner(s): Brockman, Angel T
• Application Number:
  US15/750,993
• Publication Number:
  US 20190124687A1
• Time in Patent Office: 1,257 Days
• Field of Search: 370329
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 27/0006 Assessment of spectral gaps suitable for allocating digitally modulated signals, e.g. for carrier allocation in cognitive radio for spectrum sharing between different networks H04W16/14
• CPC Class Codes: H04L 27/26 Systems using multi-frequency codes H04L27/32 takes precedence
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

Provided are a preamble transmission method and apparatus. The method comprises: a UE executing LBT on a first time frequency resource of an unlicensed carrier until a right to use the unlicensed carrier is acquired, wherein the LBT comprises LBT executed for transmitting a preamble; and after a right to use the access to the unlicensed carrier is acquired, the UE transmitting the preamble on a second time frequency resource located behind the first time frequency resource, wherein the second time frequency resource is a pre-configured PRACH time frequency resource at a fixed position, or a PRACH time frequency resource determined according to an LBT execution position. By means of the present disclosure, the problem in the relevant art of intra-cell interference caused by uplink data transmission over an unlicensed carrier is solved, and the uplink data transmission quality is improved.

Claims

1. A preamble transmission method comprising:

performing, by a user equipment UE, a Listen Before Talk LBT on a first time-frequency resource of an unlicensed carrier until obtaining a right to use the unlicensed carrier, the LBT comprising a LBT performed for transmitting a preamble; and

after obtaining the right to use the unlicensed carrier, transmitting, by the UE, at least one of the preamble, a SRS, and a PUSCH on a second time-frequency resource located after the first time-frequency resource;

or

after obtaining the right to use the unlicensed carrier, transmitting by the UE the preamble in a specific manner in frequency domain according to at least one of;

the preamble being transmitted by each user equipment in frequency domain, and a specified frequency domain interval being reserved between two second time-frequency resources or preambles,

the preamble being repeatedly transmitted N times in the frequency domain, and N preamble or second time-frequency resources in the frequency domain continuously,

the preamble being repeatedly transmitted N times in the frequency domain and a specified frequency domain interval being provided between two second time-frequency resources or preamble,

the user equipment transmitting the preamble according to a specified frequency domain pattern,

the preamble being transmitted according to modifying a subcarrier interval, and

a new preamble sequence being transmitted in the frequency domain, wherein the new preamble sequence is generated in a specific manner.

2. The method according to claim 1, wherein the first time-frequency resource comprises one of:

one orthogonal frequency division multiplexing OFDM symbol or multiple OFDM symbols before the second time-frequency resource; and

one sub-frame or multiple sub-frames before the second time-frequency resource;

wherein the second time-frequency resource comprises one sub-frame or multiple sub-frames or one OFDM symbol or multiple OFDM symbols.

8. The method according to claim 1, wherein the performing, by the UE, the LBT on the first time-frequency resource of the unlicensed carrier comprises one of:

performing, by the UE, one Clear Channel Assessment CCA detection on the first time-frequency resource;

performing, by the UE, multiple CCA detections on the first time-frequency resource;

directly performing, by the UE, Evolution Clear Channel Assessment eCCA detection on the first time-frequency resource; and

after performing one CCA detection on the first time-frequency resource, performing, by the UE, eCCA detection.

9. The method according to claim 1, wherein a physical resource block PRB occupied by the second time-frequency resource in the frequency domain is transmitted on a preset frequency domain resource, wherein the preset frequency domain resource occupies no less than a predetermined ratio of frequency domain resources of the total bandwidth of the unlicensed carrier.

10. The method according to claim 9, wherein,

the PRB occupied by the second time-frequency resource in the frequency domain and the PRBs occupied by time-frequency resources for transmitting preambles of other UEs than the UE in the frequency domain occupy the entire preset frequency domain resource at a first predetermined frequency domain interval;

or

the PRB occupied by the second time-frequency resource in the frequency domain is duplicated into multiple copies, and the multiple copies of the PRB occupy the entire preset frequency domain resource at a second frequency domain interval;

or

the PRB occupied by the second time-frequency resource in the frequency domain is duplicated into multiple copies, and the multiple copies of the PRB occupy the entire preset frequency domain resource continuously;

or

an interval of subcarriers of the PRB is modified to cause the PRB occupied by the second time-frequency resource in the frequency domain to occupy the entire preset frequency domain resource;

or

the preamble is encoded according to a specific encoding rule to cause the PRB occupied by the second time-frequency resource for transmitting the preamble in the frequency domain to occupy the entire preset frequency domain resource.

11. The method according to claim 1, wherein the first time-frequency resource or the second time-frequency resource is determined by at least one of:

high-layer RRC signaling, physical layer DCI signaling, a predefined manner, previously determined by the base station and the UE; and

the LBT completed time.

12. The method according to claim 1, wherein the subcarrier interval comprises one of:

1.25 kHz, 2.5 kHz, 3.75 kHz, 5 kHz, 7.5 kHz, 10 kHz, 15 kHz, 20 kHz, 30 kHz, 60 kHz and 120 kHz.

14. The method according to claim 1, wherein at least one of the preamble, the SRS, and the PUSCH being transmitted on a second time-frequency resource comprises one of:

if there is a certain priority for at least one of the preamble, the SRS and the PUSCH being transmitted on a second time-frequency resource, the position of one Clear Channel Assessment CCA detection corresponding to at least one of preamble, SRS and PUSCH on the first time-frequency resource can be determined according to the priority of at least one of the preamble, the SRS and the PUSCH.

15. The method according to claim 2, wherein the performing, by the UE, the LBT on the first time-frequency resource of the unlicensed carrier comprises one of:

in the case that the first time-frequency resource is one OFDM symbol, performing, by the UE, a first LBT over a first time period within said one OFDM symbol;

in the case that the first time-frequency resource is multiple OFDM symbols, performing, by the UE, the first LBT over a first time period within the first OFDM symbol of the multiple OFDM symbols or within the multiple OFDM symbols;

in the case that the first time-frequency resource is one sub-frame, performing, by the UE, the first LBT over a first time period within the first OFDM symbol of said one sub-frame or within said one sub-frame; and

in the case that the first time-frequency resource is multiple sub-frames, performing, by the UE, the first LBT over a first time period within the first OFDM symbol of the multiple sub-frames or within the first sub-frame of the multiple sub-frames or within the multiple sub-frames.

16. The method according to claim 15, wherein the performing, by the UE, the LBT on the first time-frequency resource of the unlicensed carrier further comprises at least one of:

in the case that the first time-frequency resource is one OFDM symbol, performing, by the UE, a second LBT over a second time period within said one OFDM symbol;

in the case that the first time-frequency resource is one OFDM symbol, performing, by the UE, a third LBT over a third time period within said one OFDM symbol;

in the case that the first time-frequency resource is multiple OFDM symbols, performing, by the UE, the second LBT over a second time period within the second OFDM symbol of the multiple OFDM symbols or within the multiple OFDM symbols;

in the case that the first time-frequency resource is multiple OFDM symbols, performing, by the UE, the third LBT over a third time period within the third OFDM symbol of the multiple OFDM symbols or within the multiple OFDM symbols;

in the case that the first time-frequency resource is one sub-frame, performing, by the UE, the second LBT over a second time period within the second OFDM symbol of said one sub-frame or within said one sub-frame;

in the case that the first time-frequency resource is one sub-frame, performing, by the UE, the third LBT over a third time period within the third OFDM symbol of said one sub-frame or within said one sub-frame;

in the case that the first time-frequency resource is multiple sub-frames, performing, by the UE, the second LBT over a second time period within the second OFDM symbol of the multiple sub-frames or within the second sub-frame of the multiple sub-frames or within the multiple sub-frames; and

in the case that the first time-frequency resource is multiple sub-frames, performing, by the UE, the third LBT over a third time period within the third OFDM symbol of the multiple sub-frames or within the third sub-frame of the multiple sub-frames or within the multiple sub-frames.

17. The method according to claim 16, wherein LBTs performed on different time periods comprise at least one of:

a LBT performed for transmitting a preamble, a LBT performed for transmitting a sounding reference signal SRS, and a LBT performed for transmitting Physical Uplink Shared Channel PUSCH, wherein the different time periods comprise at least one of a first time period, a second time period, and a third time period.

18. The method according to claim 16, wherein the first OFDM symbol is an OFDM symbol before the second OFDM symbol, and the second OFDM symbol is an OFDM symbol before the third OFDM symbol;

or, the first time period is a time period before the second time period, and the second time period is a time period before the third time period;

or, the first sub-frame is a sub-frame before the second sub-frame, and the second sub-frame is a sub-frame before the third sub-frame.

3. A preamble transmission method comprising:

performing, by a user equipment UE, a Listen Before Talk LBT on a first time-frequency resource of an unlicensed carrier until obtaining a right to use the unlicensed carrier, the LBT comprising a LBT performed for transmitting a preamble;

after obtaining the right to use the unlicensed carrier, transmitting, by the UE, the preamble on a second time-frequency resource located after the first time-frequency resource, wherein the second time-frequency resource is a time-frequency resource of a Physical Random Access Channel PRACH at a preconfigured fixed position, or a PRACH time-frequency resource determined according to the position for performing the LBT;

wherein the first time-frequency resource comprises one of;

one orthogonal frequency division multiplexing OFDM symbol or multiple OFDM symbols before the second time-frequency resource; and

one sub-frame or multiple sub-frames before the second time-frequency resource;

wherein the second time-frequency resource comprises one sub-frame or multiple sub-frames or one OFDM symbol or multiple OFDM symbols; and

wherein in the case that the first time-frequency resource is one sub-frame or multiple sub-frames before the second time-frequency resource, the first time-frequency resource comprises one of;

the last OFDM symbol or the last multiple OFDM symbols of one sub-frame before the second time-frequency resource; and

all or a part of OFDM symbols of multiple sub-frames before the second time-frequency resource.

4. A preamble transmission method according to comprising:

performing, by a user equipment UE, a Listen Before Talk LBT on a first time-frequency resource of an unlicensed carrier until obtaining a right to use the unlicensed carrier, the LBT comprising a LBT performed for transmitting a preamble;

after obtaining the right to use the unlicensed carrier, transmitting, by the UE, the preamble on a second time-frequency resource located after the first time-frequency resource, wherein the second time-frequency resource is a time-frequency resource of a Physical Random Access Channel PRACH at a preconfigured fixed position, or a PRACH time-frequency resource determined according to the position for performing the LBT;

wherein the first time-frequency resource comprises one of;

one orthogonal frequency division multiplexing OFDM symbol or multiple OFDM symbols before the second time-frequency resource; and

one sub-frame or multiple sub-frames before the second time-frequency resource;

wherein the second time-frequency resource comprises one sub-frame or multiple sub-frames or one OFDM symbol or multiple OFDM symbols; and

wherein the performing, by the UE, the LBT on the first time-frequency resource of the unlicensed carrier comprises one of;

in the case that the first time-frequency resource is one OFDM symbol, performing, by the UE, a first LBT over a first time period within said one OFDM symbol;

in the case that the first time-frequency resource is multiple OFDM symbols, performing, by the UE, the first LBT over a first time period within the first OFDM symbol of the multiple OFDM symbols or within the multiple OFDM symbols;

in the case that the first time-frequency resource is one sub-frame, performing, by the UE, the first LBT over a first time period within the first OFDM symbol of said one sub-frame or within said one sub-frame; and

in the case that the first time-frequency resource is multiple sub-frames, performing, by the UE, the first LBT over a first time period within the first OFDM symbol of the multiple sub-frames or within the first sub-frame of the multiple sub-frames or within the multiple sub-frames.

5. The method according to claim 4, wherein the performing, by the UE, the LBT on the first time-frequency resource of the unlicensed carrier further comprises at least one of:

in the case that the first time-frequency resource is one OFDM symbol, performing, by the UE, a second LBT over a second time period within said one OFDM symbol;

in the case that the first time-frequency resource is one OFDM symbol, performing, by the UE, a third LBT over a third time period within said one OFDM symbol;

in the case that the first time-frequency resource is multiple OFDM symbols, performing, by the UE, the second LBT over a second time period within the second OFDM symbol of the multiple OFDM symbols or within the multiple OFDM symbols;

in the case that the first time-frequency resource is multiple OFDM symbols, performing, by the UE, the third LBT over a third time period within the third OFDM symbol of the multiple OFDM symbols or within the multiple OFDM symbols;

in the case that the first time-frequency resource is one sub-frame, performing, by the UE, the second LBT over a second time period within the second OFDM symbol of said one sub-frame or within said one sub-frame;

in the case that the first time-frequency resource is one sub-frame, performing, by the UE, the third LBT over a third time period within the third OFDM symbol of said one sub-frame or within said one sub-frame;

in the case that the first time-frequency resource is multiple sub-frames, performing, by the UE, the second LBT over a second time period within the second OFDM symbol of the multiple sub-frames or within the second sub-frame of the multiple sub-frames or within the multiple sub-frames; and

in the case that the first time-frequency resource is multiple sub-frames, performing, by the UE, the third LBT over a third time period within the third OFDM symbol of the multiple sub-frames or within the third sub-frame of the multiple sub-frames or within the multiple sub-frames.

6. The method according to claim 5, wherein LBTs performed on different time periods comprise at least one of:

a LBT performed for transmitting a preamble, a LBT performed for transmitting a sounding reference signal SRS, and a LBT performed for transmitting Physical Uplink Shared Channel PUSCH, wherein the different time periods comprise at least one of a first time period, a second time period, and a third time period.

7. The method according to claim 5, wherein the first OFDM symbol is an OFDM symbol before the second OFDM symbol, and the second OFDM symbol is an OFDM symbol before the third OFDM symbol;

or, the first time period is a time period before the second time period, and the second time period is a time period before the third time period;

or, the first sub-frame is a sub-frame before the second sub-frame, and the second sub-frame is a sub-frame before the third sub-frame.

13. A preamble transmission apparatus, applied in a user equipment UE, comprising:

a performing module configured to perform a Listen Before Talk LBT on a first time-frequency resource of an unlicensed carrier until a right to use the unlicensed carrier is obtained; and

a transmitting module configured, after the right to use the unlicensed carrier is obtained, for the UE to transmit at least one of a preamble, SRS, and PUSCH on a second time-frequency resource located after the first time-frequency resource;

or;

after obtaining the right to use the unlicensed carrier, transmitting by the UE the preamble in a specific manner in frequency domain according to at least one of;

the preamble being transmitted by each user equipment in frequency domain, and a specified frequency domain interval being reserved between two second time-frequency resources or preambles,

the preamble being repeatedly transmitted N times in the frequency domain, and N preamble or second time-frequency resources in the frequency domain continuously,

the preamble being repeatedly transmitted N times in the frequency domain and a specified frequency domain interval being provided between two second time-frequency resources or preamble,

the user equipment transmitting the preamble according to a specified frequency domain pattern,

the preamble being transmitted according to modifying a subcarrier interval, and

a new preamble sequence being transmitted in the frequency domain, wherein the new preamble sequence is generated in a specific manner.