CN107294671B

CN107294671B - Method and device for sending random access subframe

Info

Publication number: CN107294671B
Application number: CN201610194904.1A
Authority: CN
Inventors: 苟伟; 彭佛才; 赵亚军; 毕峰
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2016-03-30
Filing date: 2016-03-30
Publication date: 2021-07-30
Anticipated expiration: 2036-03-30
Also published as: CN107294671A; WO2017167066A1

Abstract

The invention provides a method and a device for sending a random access subframe, wherein the method comprises the following steps: sending an uplink random access subframe on an unlicensed carrier, wherein the setting mode of the uplink random access subframe comprises at least one of the following modes: setting a clear channel assessment CCA in a random access subframe to be positioned in a first Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe, or positioning the CCA in first N continuous OFDM symbols of the subframe, wherein N is less than or equal to 3; and setting a Cyclic Prefix (CP) of a random access sequence to be transmitted from the second OFDM symbol of the subframe, and transmitting the random access sequence after the CP is transmitted, or starting the CP from a fixed sampling point, so that the problem that the uplink random access in the auxiliary authorization access LAA system is not complete is solved, and the uplink random access in the LAA system is completed.

Description

Method and device for sending random access subframe

Technical Field

The present invention relates to the field of communications, and in particular, to a method and an apparatus for transmitting a subframe for random access.

Background

Currently, communication networks of Long-Term Evolution (Long-Term Evolution, abbreviated as LTE) are all deployed in authorized carriers for operation, and with the development of LTE, some companies propose "to propose a topic for researching LTE deployment in unlicensed carriers", for example, the general companies in the united states consider that: with the rapid growth of data traffic, licensed carriers will not be able to withstand the enormous amount of data brought about by the rapid traffic growth in the near future. It is considered that data volume pressure caused by service growth can be solved by deploying LTE in an unlicensed carrier so as to share data traffic in a licensed carrier. Meanwhile, the unlicensed carrier has the following characteristics: on one hand, the unauthorized carrier does not need to be purchased, or the carrier resources have zero cost, so the unauthorized carrier is free or low in cost; on the other hand, because individuals and enterprises can participate in deployment and equipment of equipment manufacturers can also be used, the admission requirement of the unauthorized carrier wave is low; furthermore, the unlicensed carrier has sharing property, and when a plurality of different systems are operated in the unlicensed carrier or different operators of the same system operate in the unlicensed carrier, some resource sharing modes can be considered to improve the carrier efficiency.

In summary, although LTE deployment has obvious advantages in unlicensed carriers, problems still exist in the deployment process; the wireless access technology is multiple (different communication standards are crossed, cooperation is difficult, network topology is diverse), and the wireless access site is multiple (the number of users is large, cooperation is difficult, and centralized management overhead is large). Due to the fact that multiple wireless access technologies exist, various wireless systems exist in unauthorized carriers, coordination among the wireless systems is difficult, and interference is serious. Therefore, for LTE deployment in unlicensed carriers, it is still necessary to support regulation of unlicensed carriers, and most countries require that when systems are deployed in unlicensed carriers, a listen-before-talk mechanism needs to be supported. Interference between adjacent systems caused by simultaneous use of unlicensed carriers can be avoided through a listen-before-talk mechanism. And further introduces a contention backoff mechanism, that is, neighboring system stations (generally, neighboring transmission nodes of the same system) can avoid interference caused when neighboring transmission nodes of the same system use an unlicensed carrier at the same time through the contention backoff mechanism. In addition, regulations stipulate that devices (including a base station and User Equipment (UE)) using an unlicensed carrier need to perform a listen-before-talk mechanism (i.e., Clear Channel Assessment (CCA), also referred to as LBT) before transmission, and the devices can transmit data using the unlicensed carrier Channel only when the Channel is idle.

Due to the introduction of the LBT mechanism, the random access design in the existing LTE system needs to be modified to satisfy the requirement that the LTE system operates in the unlicensed carrier.

In LTE, fig. 1 is a schematic composition diagram of a subframe for uplink random access in the related art according to the present invention, as shown in fig. 1, the subframe includes a CP (cyclic prefix) and a sequence for random access (Tseq), and a guard interval (GT, that is, a channel remains idle and a device performing random access does not transmit a signal) exists after the sequence for random access in actual implementation. That is, the subframe sequentially includes CP, Tseq, and GT, and the sum of the CP, Tseq, and GT is the duration of one subframe (1ms or 30720 samples).

The UE establishes a connection with the cell through a Random Access Procedure (Random Access Procedure) and acquires uplink synchronization. Only if uplink synchronization is achieved, the UE can perform uplink transmission.

The main purpose of random access is: 1) obtaining uplink synchronization; 2) and allocating a unique identity C-RNTI for the UE.

The random access procedure is typically triggered by one of the following 6 types of events: (see section 10.1.5 of 36.300)

1) Establishing a radio connection (from an RRC _ IDLE state to an RRC _ CONNECTED state by the UE) at the time of initial access;

2) RRC Connection reestablishment procedure (RRC Connection Re-establishment procedure);

3) handover (handover);

4) in the RRC _ CONNECTED state, when downlink data arrives (ACK/NACK needs to be replied at the moment), the uplink is in an 'asynchronous' state;

5) in the RRC _ CONNECTED state, uplink data arrives (for example: need to report measurement report or send user data), the uplink is in "out-of-sync" state or there is no available PUCCH resource for SR transmission (at this time, the UE in uplink synchronization is allowed to use RACH to replace SR);

6) in the RRC _ CONNECTED state, timing advance is required for positioning the UE.

The random access procedure has a special purpose: the random access may also be used as one SR if no dedicated SR resource is configured on the PUCCH.

There are two different ways of random access procedure:

(1) competition based (competition based): applied to the first 5 events previously described;

(2) non-competition-based (Non-competition-based or competition-Free-based): only the three events (3), (4) and (6) described above are applied.

In the LTE system, one subframe has a duration of 1ms, and includes 14 OFDM symbols of equal length in the case of a standard cyclic prefix (12 OFDM symbols of equal length in the case of an extended CP).

The design of random access in the LTE system is:

the format of the random access and the corresponding parameters are shown in table 1.

TABLE 1

Formats 0 and 4 are suitable for use in small-coverage scenarios. The specific GT length is not given in table 1 (since after specifying the start of the CP and the length of the random sequence, the length of the outgoing GT can be pushed according to the end position of the subframe, and the GT does not need to transmit a signal), but can be pushed directly according to the specification in the relevant protocol, e.g. 36.211.

It is apparent that the random access mechanism in the related art cannot be directly used because of the lack of the LBT mechanism. To operate the random access of LTE in an unlicensed carrier, the characteristics of the LTE system need to be combined, and it is considered that LBT (or referred to as CCA mechanism) is introduced for random access, and the LBT mechanism affects the design of the existing random access, so the joint design of LBT mechanism and random access needs to be considered, so as to improve the random access efficiency under the LBT mechanism to the greatest extent.

After the LBT-based random access mechanism is designed, the usage methods and corresponding flows of the base station and the UE need to be further clarified, which is also one of the problems to be considered and solved.

The current random Access does not support the LBT mechanism, so it cannot be used in the LAA system, that is, it cannot directly transfer the random Access in the LTE system to the Assisted authorized Access (LAA) for use.

For the problem that the uplink random access in the auxiliary grant access LAA system is still incomplete in the related art, no effective solution exists at present.

Disclosure of Invention

The invention provides a method and a device for sending a random access subframe, which are used for at least solving the problem that uplink random access in an auxiliary authorization access LAA system in the related art is incomplete.

According to an aspect of the present invention, there is provided a method for transmitting a subframe for random access, including:

sending an uplink random access subframe on an unlicensed carrier, wherein the setting mode of the uplink random access subframe comprises at least one of the following modes:

setting a Clear Channel Assessment (CCA) in a random access subframe to be located in a first Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe, or the CCA is located in first N continuous OFDM symbols of the subframe, wherein N is less than or equal to 3;

and setting a Cyclic Prefix (CP) of a random access sequence to be transmitted from the second OFDM symbol of the subframe, and transmitting the random access sequence after the CP is transmitted, or starting to be transmitted from a fixed sampling point, wherein the fixed sampling point is positioned in the first M OFDM symbols, and M is a positive integer.

Further, a cyclic prefix CP of a random access sequence is set to start transmitting from a second OFDM symbol of the subframe, and after the CP is transmitted, the random access sequence is transmitted, specifically: starting to transmit at 2193 th sampling point in the subframe when the second OFDM symbol starts to transmit, wherein the length of the CP is 3168 sampling points, transmitting the random access sequence after the CP is transmitted, wherein the length of the random access sequence is 24576 sampling points, and setting the time of the subframe after the CCA, the random access sequence and the CP are removed as a guard interval GT after the random access sequence is transmitted, wherein the length of the subframe is 30720 sampling points;

or, setting a cyclic prefix CP of a random access sequence to start transmitting from a second OFDM symbol of the subframe, and after the CP is transmitted, transmitting the random access sequence, specifically: the first 2192 samples in the subframe are used for the CCA, 2072 samples after the CCA are used for the CP, 24576 samples after the CP are used for the random access sequence, the subframe excluding the CCA, the random access sequence and the remaining samples after the CP are used for a GT, and the GT is 1880 samples.

Or, setting a cyclic prefix CP of a random access sequence to start transmitting from a second OFDM symbol of the subframe, and after the CP is transmitted, transmitting the random access sequence, specifically: the first 2192 samples in the subframe are used for the CCA, 976 samples after the CCA are used for the CP, 24576 samples after the CP are used for the random access sequence, the subframe is used for the GT excluding the CCA, the random access sequence and the remaining samples after the CP, and the GT is 2976 samples.

Further, the CCA is set to be located in a first OFDM symbol in the subframe, where the CCA is detected as a single CCA, and when a duration is t, the CCA is always located within a duration t from the end of the first OFDM symbol.

Further, the CCA is arranged in a first OFDM symbol in the subframe, where the CCA is detected as a single CCA and has a time length of t, the CCA is arranged at any position in the first OFDM symbol, and when the CCA is detected successfully to obtain an unlicensed carrier usage right, an occupied signal is sent until a CP of the random access sequence starts to send a sample point.

Further, the occupancy signal is a CP of the extended random access sequence.

Further, when the random access sequence and the CP corresponding to the random access sequence are transmitted, the subcarrier interval adopted is 1.25 KHz.

Further, when the starting position of the CP corresponding to the random access sequence is set as a fixed sampling point and is located in the first OFDM symbol of the subframe, the CCA is located at a time length of t microseconds before the first OFDM symbol, the sampling point after the time length of t microseconds is a starting point of the CP, the lengths of the CP and the random access sequence are 3168 sampling point and 24576 sampling point respectively, and the remaining sampling points of the subframe excluding the CCA, the random access sequence and the CP are guard interval GT.

Further, when the CP of the sequence with the random access is set to transmit from a fixed sampling point as a starting point, when there is an interval from the starting point of the CP at a time point when the CCA successfully obtains the usage right of the unlicensed carrier, an occupied signal is transmitted at the interval.

Further, in the subframe of the uplink random access, the first K sampling points are used for CCA detection, the starting sampling point of the CP of the random access sequence is fixed from the K +1 sampling point, the length of the CP is 3168 sampling points, the sampling points after the CP are sampling points of the random access sequence, the length of the random access sequence is 24576 sampling points, and K is the duration of a single CCA detection corresponding to the uplink random access.

Further, when the value of K is 768, the guard interval GT of the subframe is 2208 samples.

Further, in the subframe of the uplink random access, the first H samples are used for CCA detection, the CP starting sample of the random access sequence is fixed from the H +1 th sample, the random access sequence is located after the CP, the length of the random access sequence is 24576 samples, the GT is located after the CP, the length of the GT is 2976 samples, where H is the duration of a single CCA detection corresponding to the uplink random access.

Further, when the value of H is 768, the length of the CP is 2400 samples.

Further, in the subframe for uplink random access, the structure of the subframe includes: the following are sequentially performed from the end of the subframe to the front: the length of the GT is Q1 sampling points, the length of the random access sequence is 24576 sampling points, the length of the CP is Q2 sampling points, and after the GT, the random access sequence and the CP are removed from the subframe, the remaining sampling points of the subframe are CCA execution intervals.

Further, Q1 takes the value 288, Q2 takes the value 288, and the CCA execution interval is:

30720-288-24576-5568 samples.

Further, in the subframe of the uplink random access, a CP starting sample point corresponding to the random access sequence is fixed to be a Q3+1 th sample point, and the random access sequence is arranged after the CP, wherein the length of the CP is Q4 sample points, the length of the random access sequence is 24576 sample points, and the remaining sample points excluding the CCA, the random access sequence and the CP in the sample points of the subframe are GT, wherein Q3 is determined according to a duration reserved for the CCA execution position.

Further, Q4 takes the value 288, the CCA is placed at the front of the subframe, the duration of the CCA execution position is 5568 samples, and Q3 is 5568.

Further, in the subframe of the uplink random access, a CP starting sample point corresponding to the random access sequence is fixed to be Q5+1, and the random access sequence is located after the CP, wherein the length of the CP is Q6 sample points, the length of the random access sequence is 24576 sample points, and after the CCA, the random access sequence and the CP are removed from the subframe, the remaining sample points are GT.

Further, the GT is 576 samples, the CCA is located at the first 2400 samples in the subframe, the value of Q5 is 2400, and the value of Q6 is 3168.

According to another aspect of the present invention, there is also provided a transmission apparatus of a subframe for random access, including:

a sending module, configured to send an uplink random access subframe on an unlicensed carrier, where a setting manner of the uplink random access subframe includes at least one of:

The method and the device send the uplink random access subframe on the unlicensed carrier, wherein the setting mode of the uplink random access subframe comprises at least one of the following modes: setting a clear channel assessment CCA in a random access subframe to be positioned in a first Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe, or positioning the CCA in first N continuous OFDM symbols of the subframe, wherein N is less than or equal to 3; and setting a Cyclic Prefix (CP) of a random access sequence to be transmitted from the second OFDM symbol of the subframe, and transmitting the random access sequence after the CP is transmitted, or starting the CP to be transmitted from a fixed sampling point, wherein the fixed sampling point is positioned in the first M OFDM symbols, and M is a positive integer, so that the problem that the uplink random access in the auxiliary authorization access LAA system is not complete is solved, and the uplink random access in the LAA system is completed.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

fig. 1 is a schematic composition diagram of a subframe for uplink random access according to a related art of the present invention;

fig. 2 is a flow chart of transmission of a subframe for random access according to an embodiment of the present invention;

fig. 3 is a block diagram of a transmitting apparatus of a subframe for random access according to an embodiment of the present invention;

fig. 4 is a first schematic subframe structure of uplink random access designed for the LAA system according to the preferred embodiment of the present invention;

fig. 5 is a second schematic subframe structure of uplink random access designed for the LAA system according to the preferred embodiment of the present invention;

fig. 6 is a third schematic subframe structure of uplink random access designed for the LAA system according to the preferred embodiment of the present invention;

fig. 7 is a fourth schematic subframe structure of uplink random access designed for the LAA system according to the preferred embodiment of the present invention;

fig. 8 is a fifth schematic subframe structure of uplink random access designed for the LAA system according to the preferred embodiment of the present invention;

fig. 9 is a sixth schematic subframe structure of uplink random access designed for the LAA system according to the preferred embodiment of the present invention;

fig. 10 is a seventh schematic subframe structure of uplink random access designed for the LAA system according to the preferred embodiment of the present invention;

fig. 11 is a first diagram illustrating an uplink-downlink timing relationship in accordance with a preferred embodiment of the present invention;

fig. 12 is a diagram illustrating uplink-downlink timing relationship according to a preferred embodiment of the present invention.

Detailed Description

The invention will be described in detail hereinafter with reference to the accompanying drawings in conjunction with embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

In this embodiment, a method for sending a subframe for random access is provided, and fig. 2 is a flowchart for sending a subframe for random access according to an embodiment of the present invention, and as shown in fig. 2, the flowchart includes the following steps:

step S202, the setting mode of setting the uplink random access subframe includes at least one of the following: setting a clear channel assessment CCA in a random access subframe to be positioned in a first Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe, or positioning the CCA in first N continuous OFDM symbols of the subframe, wherein N is less than or equal to 3; setting a Cyclic Prefix (CP) of random access to transmit from the second OFDM symbol of the subframe, and after the CP is transmitted, transmitting a random access sequence, or starting to transmit from a fixed sampling point, wherein the fixed sampling point is positioned in the first M OFDM symbols, and M is a positive integer;

step S204, sending the uplink random access subframe on the unauthorized carrier.

Through the steps, the subframe of the uplink random access is sent on the unlicensed carrier, wherein the setting mode of the subframe of the uplink random access comprises at least one of the following modes: setting a clear channel assessment CCA in a random access subframe to be positioned in a first Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe, or positioning the CCA in first N continuous OFDM symbols of the subframe, wherein N is less than or equal to 3; and setting a Cyclic Prefix (CP) of a random access sequence to be transmitted from the second OFDM symbol of the subframe, and transmitting the random access sequence after the CP is transmitted, or starting the CP to be transmitted from a fixed sampling point, wherein the fixed sampling point is positioned in the first M OFDM symbols, and M is a positive integer, so that the problem that the uplink random access in the auxiliary authorization access LAA system is not complete is solved, and the uplink random access in the LAA system is completed.

In the embodiment of the present invention, a cyclic prefix CP of a random access sequence is set to start sending from a second OFDM symbol of the subframe, and after the CP is sent, the random access sequence is sent, specifically: starting to transmit at 2193 th sampling point in the subframe when the second OFDM symbol starts to transmit, wherein the length of the CP is 3168 sampling points, transmitting the random access sequence after the CP is transmitted, wherein the length of the random access sequence is 24576 sampling points, and setting the time of the subframe after the CCA, the random access sequence and the CP are removed as a guard interval GT after the random access sequence is transmitted, wherein the length of the subframe is 30720 sampling points;

In the embodiment of the present invention, the CCA is set to be located in a first OFDM symbol in the subframe, where the CCA detection is single CCA detection, and when a duration is t, the CCA is always located within a duration t from the end of the first OFDM symbol.

In the embodiment of the present invention, the CCA is set to be located in a first OFDM symbol in the subframe, where the CCA is detected as a single CCA and has a time length of t, the CCA is located at any position in the first OFDM symbol, and when the CCA is detected successfully to obtain an unlicensed carrier usage right, an occupied signal is sent until a CP of the random access sequence starts to send a sample point.

In an embodiment of the present invention, the occupancy signal is a CP of an extended random access sequence.

In the embodiment of the present invention, when the random access sequence and the CP corresponding to the random access sequence are transmitted, the subcarrier interval adopted is 1.25 KHz.

In the embodiment of the present invention, when a starting position of a CP corresponding to the random access sequence is set as a fixed sampling point and is located in a first OFDM symbol of the subframe, the CCA is located at a time length of t microseconds before the first OFDM symbol, a sampling point after the time length of t microseconds is a starting point of the CP, lengths of the CP and the random access sequence are 3168 sampling point and 24576 sampling point respectively, and remaining sampling points of the subframe excluding the CCA, the random access sequence and the CP are guard interval GT.

In the embodiment of the invention, when the CP of the sequence with the random access is set to be sent from a fixed sampling point as a starting point, when an interval exists between the time point when the CCA successfully obtains the use right of the unauthorized carrier and the starting point of the CP, an occupation signal is sent at the interval.

In the embodiment of the present invention, in the subframe of uplink random access, the first K samples are used for CCA detection, the sample is fixed as a CP starting sample of the random access sequence from the K +1 th sample, and the length of the CP is 3168 samples, the samples after the CP are samples of the random access sequence, and the length of the random access sequence is 24576 samples, where K is a duration of a single CCA detection corresponding to the uplink random access.

In the embodiment of the present invention, when K is 768, the guard interval GT of the subframe is 2208 samples.

In the embodiment of the present invention, in the subframe of the uplink random access, the first H samples are used for CCA detection, a CP starting sample of the random access sequence is fixed from an H +1 th sample, the CP is followed by the random access sequence, the length of the random access sequence is 24576 samples, the CP is followed by a GT, the length of the GT is 2976 samples, where H is a duration of a single CCA detection corresponding to the uplink random access.

In the embodiment of the present invention, when the value of H is 768, the length of the CP is 2400 samples.

In the embodiment of the present invention, in the subframe for setting uplink random access, the structure of the subframe includes: the following are sequentially performed from the end of the subframe to the front: the length of the GT is Q1 sampling points, the length of the random access sequence is 24576 sampling points, the length of the CP is Q2 sampling points, and after the GT, the random access sequence and the CP are removed from the subframe, the remaining sampling points of the subframe are CCA execution intervals.

In the embodiment of the present invention, the value of Q1 is 288, the value of Q2 is 288, and the CCA execution interval is:

30720-288-24576-5568 samples.

In the embodiment of the present invention, in the subframe in which the uplink random access is set, a CP starting sample point corresponding to the random access sequence is fixed to be a Q3+1 th sample point, and the random access sequence is set after the CP, where the length of the CP is Q4 sample points, the length of the random access sequence is 24576 sample points, and the remaining sample points excluding the CCA, the random access sequence and the CP in the sample points of the subframe are GT, where Q3 is determined according to a duration reserved for a CCA execution position.

In the embodiment of the present invention, Q4 takes the value 288, the CCA is placed at the front of the subframe, the duration of the CCA execution position is 5568 samples, and Q3 is 5568.

In the embodiment of the present invention, in the subframe where the uplink random access is set, a CP starting sample point corresponding to the random access sequence is fixed to be a Q5+1 th sample point, and the random access sequence is located after the CP, where the length of the CP is Q6 sample points, the length of the random access sequence is 24576 sample points, and after the CCA, the random access sequence, and the CP are removed from the subframe, the remaining sample points are GT.

In the embodiment of the present invention, the GT has 576 samples, the CCA is located at the first 2400 samples in the subframe, the value of Q5 is 2400, and the value of Q6 is 3168.

In this embodiment, a sending apparatus of a random access subframe is further provided, and the apparatus is used to implement the foregoing embodiments and preferred embodiments, and the description already made is omitted for brevity. As used below, the term "module" may be a combination of software and/or hardware that implements a predetermined function. Although the means described in the embodiments below are preferably implemented in software, an implementation in hardware, or a combination of software and hardware is also possible and contemplated.

Fig. 3 is a block diagram of a transmitting apparatus of a random access subframe according to an embodiment of the present invention, and as shown in fig. 3, the apparatus includes:

a setting module 32, configured to set a setting mode of the uplink random access subframe, where the setting mode includes at least one of: setting a clear channel assessment CCA in a random access subframe to be positioned in a first Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe, or positioning the CCA in first N continuous OFDM symbols of the subframe, wherein N is less than or equal to 3; setting a Cyclic Prefix (CP) of random access to transmit from the second OFDM symbol of the subframe, and after the CP is transmitted, transmitting a random access sequence, or starting to transmit from a fixed sampling point, wherein the fixed sampling point is positioned in the first M OFDM symbols, and M is a positive integer;

a sending module 34, configured to send the uplink random access subframe on the unlicensed carrier.

By the above apparatus, the setting module 32 is configured to set a setting mode of the uplink random access subframe, including at least one of: setting a clear channel assessment CCA in a random access subframe to be positioned in a first Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe, or positioning the CCA in first N continuous OFDM symbols of the subframe, wherein N is less than or equal to 3; a cyclic prefix CP for random access is set to start sending from the second OFDM symbol of the subframe, and after the CP is sent, a random access sequence is sent, or the CP starts sending from a fixed sampling point, where the fixed sampling point is located in the first M OFDM symbols, M is a positive integer, a sending module 34 is configured to send an uplink random access subframe on an unlicensed carrier, which solves the problem that uplink random access in an assisted-grant access LAA system is still incomplete, and improves uplink random access in the LAA system.

The present invention will be described in detail with reference to preferred examples and embodiments.

Example 1

In one embodiment, the structure of uplink random access with CCA mechanism and the corresponding subframe structure are illustrated. At this time, the CCA is limited to the first symbol of the subframe where the random access sequence transmission is performed, and the CCA mode at this time may be a single CCA or a CCA with a random backoff window having a small value range, for example, the sum of the maximum value of the random backoff window and the first single CCA (CCA detection in a delay period) does not exceed the total duration of one OFDM symbol.

Fig. 4 is a first schematic subframe structure of uplink random access designed in the LAA system according to the preferred embodiment of the present invention, and the subframe structure includes (also represents a time sequence): gap, CCA, CP (CP corresponding to the Tseq sequence), Tseq and GT, and the total duration is one subframe duration. The CP maps from the second symbol. When the equipment determines that uplink random access needs to be executed and the subframes of the uplink random access arrive, the equipment sequentially executes corresponding operations of different functions according to the subframe structure composition sequence, so that the sending of the random access sequence in the unlicensed carrier is completed. When CCA detection is idle, the equipment sends an uplink random access sequence, otherwise, the equipment cannot send the uplink random access sequence.

If a single CCA is performed, for example, the duration of performing the single CCA is 25us, then there are several specific embodiments of performing the single CCA at this time, and one of the following may be selected to perform:

1) the specific location of the CCA is not limited within the first symbol as long as it is within the first symbol.

2) The CCA is restricted to always be located at the end of the first OFDM symbol, e.g. 25us at the end. Fig. 5 is a second subframe structure of uplink random access designed in the LAA system according to the preferred embodiment of the present invention, as illustrated in fig. 5. (in a specific implementation, if the device cannot understand the transition from the receiving state to the transmitting state after the device finishes the CCA, the starting point of the CCA is moved forward by a time t, where t is the time required for the device to transition from the receiving state to the transmitting state.)

In fig. 4, the CP length at this time is maintained as the CP length of the current LTE random access format 0, for example, the CP is duration of 3168 samples (Ts), and Tseq is 24576 samples. Ts is defined by the Ts duration of the reference LTE system. Then, the duration of the first symbol, the CP duration, and the Tseq duration are subtracted from the duration of 1ms (corresponding to 30720 samples), and the remaining duration is the duration of the guard interval GT (the number of samples is 30720 and 3168 and 24576, respectively, i.e. the stations in these samples do not transmit data). Each OFDM symbol corresponds to 1/14ms in duration, and the number of corresponding samples is defined as 2192 samples. CP is always transmitted starting with the second symbol, followed by Tseq and using a subcarrier spacing of 1.25 Khz.

Alternatively, the scheme in fig. 4 may also be described as that, in the subframe of the uplink random access, the starting time of the uplink random access sequence (including the corresponding CP) transmission is calculated from the end of the subframe to the front. For example, 784+24576+3168 samples are estimated from the end of the subframe forward as the transmission start samples of the uplink random access sequence.

The non-declared part is made with reference to the design of existing LTE systems (e.g. Release 13).

The design of the above embodiment 1 is beneficial to determining the starting sampling point of the uplink random access sequence, because the starting sampling point is exactly located at the symbol boundary, which is beneficial to implementation. Meanwhile, the whole process is finished in one subframe, and the number of the reserved sampling points for the GT is large enough, so that the coverage requirement of the LAA as a small cell can be met.

Example 2

In another preferred embodiment, fig. 6 is a schematic three of a subframe structure of uplink random access designed for the LAA system according to the preferred embodiment of the present invention, as illustrated in fig. 6. As shown in fig. 6, at this time, the CCA is limited to the first symbol of the subframe where the random access sequence transmission is performed, and the CCA mode may be a single CCA or a CCA with a random backoff window having a small value range, for example, the maximum value of the random backoff window plus the first single CCA (CCA detection for a delay period) does not exceed the total duration of one OFDM symbol.

The subframe structure in fig. 6 includes (also representing a time sequence) CCA, CP (CP corresponding to Tseq sequence), Tseq, and GT, and the total duration is one subframe duration. The CP performs transmission immediately after the CCA is successful, or the transmission of the CP is at a fixed sample point. When the equipment determines that uplink random access needs to be executed and the subframes of the uplink random access arrive, the equipment sequentially executes corresponding operations of different functions according to the subframe structure composition sequence, so that the sending of the random access sequence in the unlicensed carrier is completed. When CCA detection is idle, the equipment sends an uplink random access sequence, otherwise, the equipment cannot send the uplink random access sequence.

1) the specific location of the CCA is not limited within the first symbol as long as it is within the first symbol and before the specified CP starting point.

2) The CCA is restricted to always be located at the beginning of the first OFDM symbol, e.g., the first 25us of the beginning.

Assuming that the CCA detection determined for the uplink random access is 25us (corresponding to 768 samples) for a single CCA, the CCA may be fixed in the first 25us of the first symbol of the subframe of the uplink random access (in order to account for a certain time error in the time direction, a time duration slightly longer than 25us, for example, 34us, may be allocated by the base station, and only 25us of CCA detection needs to be performed in the time duration, and it is sufficient that the time duration is idle), so that the position of the starting point (sample) of the CP may be determined, that is, the starting sample of the CP starts to be transmitted after 25, that is, the starting sample of the CP is 768+ 1.

In another embodiment, fig. 7 is a fourth schematic subframe structure of uplink random access designed for an LAA system according to a preferred embodiment of the present invention, as shown in fig. 7, a starting sample point of a fixed CP is a time reserved for CCA detection between a starting point of a subframe and a starting sample point of a CP (the time period has a larger redundant duration, and the larger duration is favorable for a device to continue to perform a next CCA after a first CCA detection fails, so that a preemption opportunity of the device is actually increased). The occupied signal at this time can be an extended CP, that is, a part of the CP corresponding to Tseq is cut and repeated to be used as the occupied signal, which means that the length of the CP is increased, and the coverage is favorably expanded.

Within the first symbol, a duration sufficient for the device to perform CCA a number of times, for example 2 times, i.e. 50us, is reserved, after which the starting sample of the CP is fixed.

Each OFDM symbol corresponds to 1/14ms in duration, and the number of corresponding samples is defined as 2192 samples. CP is always transmitted starting with the second symbol, followed by Tseq and using a subcarrier spacing of 1.25 Khz.

Example 3

In another preferred embodiment, fig. 8 is a fifth schematic diagram of a subframe structure of uplink random access designed for an LAA system according to a preferred embodiment of the present invention, where, as shown in fig. 8, the CCA is limited to the first symbol of a subframe where random access sequence transmission is performed, and the CCA mode may perform single CCA or CCA with a random backoff window with a small value range, for example, the maximum value of the random backoff window plus the first single CCA (CCA detection for a delay period) does not exceed the total duration of one OFDM symbol.

The subframe structure in fig. 8 includes (also representing a time sequence) CCA, CP (CP corresponding to Tseq sequence), Tseq, and GT, and the total duration is one subframe duration. The CP performs transmission immediately after the CCA is successful, or the transmission of the CP is at a fixed sample point. When the equipment determines that uplink random access needs to be executed and the subframes of the uplink random access arrive, the equipment sequentially executes corresponding operations of different functions according to the subframe structure composition sequence, so that the sending of the random access sequence in the unlicensed carrier is completed. When CCA detection is idle, the equipment sends an uplink random access sequence, otherwise, the equipment cannot send the uplink random access sequence.

If a single CCA is performed, for example, the duration of performing the single CCA is 25us, then the following specific ways of performing the single CCA may exist at this time:

referring to fig. 8, the reserved device performs CCA a plurality of times, for example, 4 times, i.e., 100us, in the first few symbols of the subframe, and then fixes the starting sample point of the CP. The remaining duration in the subframe at this time: a sufficient duration of Tseq is required (here Tseq for LTE system random access format 0) as well as the duration of the CP and the GT (the respective duration of the CP and the GT at least satisfies a radius covering 1.4km, scaled to about at least 288 samples). That is to say that the duration of time left for a device to perform CCA detection is at most: 181.25us (about 30720-. 181.25us is larger than the CCA detection allowed to be performed 7 times, that is, 7 contention opportunities are continuously provided for the device, which is beneficial to the transmission of the uplink random access sequence. Based on the example here, the starting sampling point of the CP corresponding to the fixed Tseq at this time is 5568+1 th sampling point in the subframe.

Obviously, the duration of performing CCA detection reserved in a subframe may be determined according to the GT, CP determined in advance. This example also gives a method of determining the CCA execution duration in a subframe. In this example, if the CCA is successful and the end point is spaced from the fixed CP starting point, an occupied signal needs to be transmitted. The occupancy signal may be an extended CP.

Example 4

In another preferred embodiment, fig. 9 is a six schematic diagram of a subframe structure of uplink random access designed for an LAA system according to a preferred embodiment of the present invention, as illustrated in fig. 9, this way is based on the minimized modification of the existing LTE uplink random access format 0, so that it is better combined with CCA to meet the requirement of unlicensed carrier.

In fig. 9, only the GT length in format 0 of the existing uplink random access is modified, which is derived from the coverage requirement of the LAA cell, for example, the length of a given GT is b samples (for example, considering the actual coverage requirement, it can be set to 18.7 us/576 samples per month, and the coverage radius is about 2.8 km). The Tseq sequence and CP keep the length of the existing format 0, and then the starting sample point of CP is calculated from the end of the subframe forward, taking the above example as an example, at this time, the number of the samples remaining in the subframe is 30720-. The UE starts the CP transmission of the random access sequence at the agreed starting sample point of the CP (the same is true for the above embodiment), and then the base station considers that the CP of the random access sequence is the CP of the random access sequence that the UE starts to transmit from 2400+1 sample points. At this time, the execution interval of the sub-frame CCA is 0 to 2400 sampling points, a specific CCA execution position may be limited in the interval, or may not be limited, when the UE executes CCA and detects that the channel is idle, the UE needs to determine whether the initial sampling point of the CP arrives, and if the initial sampling point of the CP arrives, the CP is directly sent, otherwise, the UE needs to send an occupation signal to occupy the channel until the initial sampling point of the CP arrives.

Example 5

In another preferred embodiment, fig. 10 is a seventh schematic diagram of a subframe structure of uplink random access designed in an LAA system according to a preferred embodiment of the present invention, as shown in fig. 10, which is based on a minimum modification to the existing LTE uplink random access format 0, so that it is better combined with CCA to meet the requirement of an unlicensed carrier.

In fig. 10, a random access subframe structure is: the position interval of CCA execution is given, and according to the sequence of CCA execution, for example, when a single CCA detection is performed and the duration is 25us, 768 samples are corresponded (other values may also be, only similar calculation needs to be performed). The CP is then sent immediately after, but the length of the CP is reduced by 768 samples, in this case 2400 samples. Then follows the sequence of random access, 24576 samples, followed by GT, 2976 samples.

If the size of the CCA execution location interval is further changed, for example, it becomes larger, and provides more than 2 CCA opportunities, then the CP samples need to be further reduced, but in consideration of coverage, the CP has a minimum of 288 samples (this is determined according to the coverage radius of the LAA cell, and if other types of cells correspond to other values); if it is then necessary to further increase the interval for CCA performance, it is necessary to reduce the duration of GT, which is also related to coverage, by a minimum of 288 (with CP). The interval of CCA execution is increased, the device may try a plurality of CCA opportunities in the interval, and may send uplink random access if any CCA detection is successful.

Example 6

As shown in table 2, the preferred random access subframe structure in the present application, the CP of the uplink random access of the LAA system, and the length of the random access sequence are given in the form of a table below (including but not limited thereto). The number of samples of one subframe describes:

TABLE 2

Description of the drawings: the CCA interval is always located in front of the subframe. And the CCA execution interval means: for example 2192. multidot.T_sIndicating that the 1 st sampling point to the 2192 th sampling point in the subframe are all CCA execution intervals. GT is always located at the end of a subframe, e.g. GT is 2208Ts in length, meaning that the last 2208 samples in the subframe are GT.

The above embodiments are not specifically described, and all of them are considered to adopt the same sequence and transmission scheme as the uplink random access format 0 in LTE 36.211, for example, the subcarrier interval is 1.25KHz, and the CP corresponding to the uplink random sequence is included. If the device successfully performs CCA in the first OFDM symbol in the subframe, the device starts to transmit the extended CP from the CCA successful time until the start point of the CP corresponding to the specified random access sequence, and then starts to transmit the corresponding CP, all using 1.25KHz subcarrier intervals. The extended CP may be considered to be a time-domain extension or repetition of the corresponding CP.

Example 7

In LTE in the related art, a sequence and CP of uplink random access are transmitted from a subframe boundary, and a corresponding N is calculated_TA(for the definition in the existing LTE, refer to 36.211vd00), fig. 11 is a schematic diagram of uplink-downlink timing relationship according to the preferred embodiment of the present invention, and the relevant parameters in fig. 11 refer to 36.211vd00 protocol.

However, it is considered that a sequence of actual uplink random access and a CP transmission time point have an interval N with respect to a subframe start boundary due to the CCA located in the first symbol of the subframe_TAFS3(the number of samples from the time point of actually sending the CP (excluding the extended CP or the occupied signal) corresponding to the random access sequence to the starting time point of the subframe) is several samples. Then N is calculated_TAWhen the base station needs to obtain N in the existing measurement_TAAfter the value, subtract 2 × N_TAFS3(or subtracting N again)_TAFS3)。

Example 8

Embodiment 8 provides a PRACH subframe determination method due to arbitrary configuration in UL/DL subframes in an unlicensed carrier.

In the LAA system, the PRACH radio frame and subframe configuration in the existing LTE is used, for example, the subframe configuration Table (for example, Table 5.7.1-2 in 36.211vd00) in the existing FDD mode is used, and only the configuration related to the format 0 in the Table is used here.

The specific PRACH subframe is determined as follows:

when the UE receives DCI signaling of a PDCCH triggering a PRACH sent by a base station, the UE (or the base station) follows one or more of the following:

1) and the System frame number is used for determining the frame number of the Pcell corresponding to the unauthorized carrier if the frame number cannot be determined in the unauthorized carrier. And if the LAA carrier has the determined frame number signaling transmission, using the frame number determination in the non-authorization.

2) In the unlicensed carrier, when a certain subframe is determined to be configured as a PRACH resource subframe according to the table and the subframe is not configured as a downlink subframe by the base station (during occupied transmission), the subframe can be used for PRACH sequence transmission (or reception).

When it is determined that the subframe is configured as a PRACH resource subframe but has been configured as a downlink subframe by the base station (during an occupied transmission), then the subframe is determined as a downlink subframe, not used for PRACH sequence transmission (or reception).

The downlink subframe includes a subframe for transmitting a PDSCH, or a subframe for transmitting a downlink discovery signal DRS (or multiple candidate subframes in a period for transmitting a DRS), or a partial downlink subframe (for format 0).

3) In an unlicensed carrier, when it is determined that a subframe is configured as a PRACH resource subframe according to the table and the subframe is a last downlink subframe of a transmission period occupied by a base station, a UE determines whether the subframe is used for transmitting a PRACH according to the following manner: and the UE receives a DCI signaling triggering the PRACH, and if the last downlink subframe is determined to be a partial subframe and the number of the remaining symbols exceeds 2, the UE considers that the subframe is configured with the transmission of the PRACH format 4.

Fig. 12 is a diagram illustrating a second uplink-downlink timing relationship according to a preferred embodiment of the present invention, and as shown in fig. 12, the second uplink-downlink timing relationship is when an example is an unlicensed carrier, a CCA is located in a first symbol of a random access subframe, and a sequence of uplink random access and a CP start transmission from a fixed sampling point after the CCA is successful.

Through the above description of the embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but the former is a better implementation mode in many cases. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium (e.g., ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal device (e.g., a mobile phone, a computer, a server, or a network device) to execute the method according to the embodiments of the present invention.

It should be noted that, the above modules may be implemented by software or hardware, and for the latter, the following may be implemented, but not limited to: the modules are all positioned in the same processor; alternatively, the modules are respectively located in a plurality of processors.

The embodiment of the invention also provides a storage medium. Alternatively, in the present embodiment, the storage medium may be configured to store program codes for performing the following steps:

s1, setting the subframe of the uplink random access, wherein the setting mode includes at least one of the following: setting a clear channel assessment CCA in a random access subframe to be positioned in a first Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe, or positioning the CCA in first N continuous OFDM symbols of the subframe, wherein N is less than or equal to 3; setting a Cyclic Prefix (CP) of random access to transmit from the second OFDM symbol of the subframe, and after the CP is transmitted, transmitting a random access sequence, or starting to transmit from a fixed sampling point, wherein the fixed sampling point is positioned in the first M OFDM symbols, and M is a positive integer;

and S2, sending the uplink random access subframe on the unlicensed carrier.

Optionally, the storage medium is further arranged to store program code for performing the method steps of the above embodiments:

optionally, in this embodiment, the storage medium may include, but is not limited to: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.

Optionally, in this embodiment, the processor executes the method steps of the above embodiments according to the program code stored in the storage medium.

Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments and optional implementation manners, and this embodiment is not described herein again.

It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for transmitting a subframe for random access, comprising:

and setting a Cyclic Prefix (CP) of a random access sequence to be transmitted from the second symbol of the subframe, and transmitting the random access sequence after the CP is transmitted, or starting to be transmitted from a fixed sampling point, wherein the fixed sampling point is positioned in the first M OFDM symbols, and M is a positive integer.

2. The method according to claim 1, wherein a Cyclic Prefix (CP) of a random access sequence is set to be transmitted from a second OFDM symbol of the subframe, and after the CP is transmitted, the random access sequence is transmitted, specifically: starting to transmit at 2193 th sampling point in the subframe when the second OFDM symbol starts to transmit, wherein the length of the CP is 3168 sampling points, transmitting the random access sequence after the CP is transmitted, wherein the length of the random access sequence is 24576 sampling points, and setting the time of the subframe after the CCA, the random access sequence and the CP are removed as a guard interval GT after the random access sequence is transmitted, wherein the length of the subframe is 30720 sampling points;

or, setting a cyclic prefix CP of a random access sequence to start transmitting from a second OFDM symbol of the subframe, and after the CP is transmitted, transmitting the random access sequence, specifically: the first 2192 sampling points in the subframe are used for the CCA, 2072 sampling points after the CCA are used for the CP, 24576 sampling points after the CP are used for the random access sequence, the CCA, the random access sequence and the remaining sampling points after the CP are removed from the subframe are used for a GT, and the GT is 1880 sampling points;

3. The method of claim 2,

and setting the CCA to be located in a first OFDM symbol in the subframe, wherein the CCA detection is single CCA detection, and when the duration is t, the CCA is always located in the t duration at the tail of the first OFDM symbol.

4. The method of claim 2,

and setting the CCA to be located in a first OFDM symbol in the subframe, wherein the CCA is detected as single CCA and is located at any position in the first OFDM symbol when the duration is t, and after the CCA is successfully detected and the use right of an unauthorized carrier is obtained, an occupation signal is sent until a CP of the random access sequence starts to send samples.

5. The method of claim 4,

the occupancy signal is a CP of the extended random access sequence.

6. The method of claim 1,

and when the random access sequence and the CP corresponding to the random access sequence are sent, the interval of the adopted subcarriers is 1.25 KHz.

7. The method of claim 1,

when the starting position of the CP corresponding to the random access sequence is set to be a fixed sampling point and is located in the first OFDM symbol of the subframe, the CCA is located in the first t microseconds of the first OFDM symbol, the sampling point after the time of the t microseconds is the starting point of the CP, the lengths of the CP and the random access sequence are 3168 sampling point and 24576 sampling point respectively, and the remaining sampling points after the CCA, the random access sequence and the CP are removed from the subframe are guard interval GT.

8. The method of claim 1,

when the CP of the sequence of the random access is set to be sent from a fixed sampling point as a starting point, when an interval exists between the time point when the CCA successfully obtains the use right of the unauthorized carrier and the starting point of the CP, an occupation signal is sent at the interval.

9. The method of claim 1,

in the subframe of uplink random access, the first K sampling points are used for CCA detection, the K +1 sampling point is fixed as a CP starting sampling point of the random access sequence, the length of the CP is 3168 sampling points, the sampling points behind the CP are sampling points of the random access sequence, the length of the random access sequence is 24576 sampling points, and K is the duration of single CCA detection corresponding to the uplink random access.

10. The method of claim 9,

and when the value of K is 768, the guard interval GT of the subframe is 2208 sampling points.

11. The method of claim 1,

and setting the first H sampling points in the subframe of uplink random access for CCA detection, fixing the first H +1 sampling points as CP starting sampling points of the random access sequence, wherein the CP is followed by the random access sequence, the length of the random access sequence is 24576 sampling points, the CP is followed by a GT, the length of the GT is 2976 sampling points, and H is the duration of single CCA detection corresponding to the uplink random access.

12. The method of claim 11,

and when the H value is 768, the length of the CP is 2400 sampling points.

13. The method of claim 1,

in the subframe for uplink random access, the structure of the subframe comprises: the following are sequentially performed from the end of the subframe to the front: the length of the GT is Q1 sampling points, the length of the random access sequence is 24576 sampling points, the length of the CP is Q2 sampling points, and after the GT, the random access sequence and the CP are removed from the subframe, the remaining sampling points of the subframe are CCA execution intervals.

14. The method of claim 11,

q1 takes the value 288, Q2 takes the value 288, the CCA execution interval is:

30720-288-24576-5568 samples.

15. The method of claim 1,

in the subframe of uplink random access, fixing a CP starting sampling point corresponding to the random access sequence as a Q3+1 th sampling point, and setting the CP to be followed by the random access sequence, wherein the length of the CP is Q4 sampling points, the length of the random access sequence is 24576 sampling points, and the remaining sampling points excluding the CCA, the random access sequence and the CP in the sampling points of the subframe are GT, wherein Q3 is determined according to a duration reserved for a CCA execution position.

16. The method of claim 15,

the value of Q4 is 288, the CCA is placed at the front of the subframe, the duration of the CCA execution position is 5568 samples, and Q3 is 5568.

17. The method of claim 1,

in the subframe of uplink random access, fixing a starting sample point of a CP corresponding to the random access sequence as a Q5+1 th sample point, and after the CP, determining the random access sequence, wherein the length of the CP is Q6 sample points, the length of the random access sequence is 24576 sample points, and after the CCA, the random access sequence and the CP are removed from the subframe, remaining sample points are GT.

18. The method of claim 17,

the GT is 576 samples, the CCA is located at the first 2400 samples in the subframe, the value of Q5 is 2400, and the value of Q6 is 3168.

19. A transmission apparatus of a subframe for random access, comprising: