WO2016054969A1

WO2016054969A1 - Method and system of contending for right to use unlicensed carrier, and contention fallback method

Info

Publication number: WO2016054969A1
Application number: PCT/CN2015/090175
Authority: WO
Inventors: 苟伟; 彭佛才; 赵亚军; 夏树强
Original assignee: 中兴通讯股份有限公司
Priority date: 2014-10-10
Filing date: 2015-09-21
Publication date: 2016-04-14
Also published as: CN105578609A

Abstract

A method and system of contending for the right to use an unlicensed carrier, and a contention fallback method, comprising: transmission nodes each randomly generate a serial number of a first fallback time point of respective first contention fallback windows; the respective transmission nodes simultaneously monitor an unlicensed carrier within the respective first contention fallback windows; before the serial number of the first fallback time point is reached, if the monitored unlicensed carrier is continuously idle, then the transmission nodes continue to contend for the right to use the unlicensed carrier within a second contention fallback window; if the monitored unlicensed carrier is continuously occupied, then the transmission nodes stop contending for the right to use the unlicensed carrier; a transmission node successfully obtaining the right to use the unlicensed carrier through contention within the second contention fallback window transmits data on the unlicensed carrier. In the above technical solution, transmission nodes contend for the right to use the unlicensed carrier within the first and second contention time windows, and only one transmission node can obtain the right, avoiding channel interference caused by contention conflicts; in addition, the contention for the right to use the unlicensed carrier is fair and the unlicensed carrier is rationally utilized.

Description

Method, system and competitive fallback method for realizing unlicensed carrier usage right competition

Technical field

This document relates to, but is not limited to, the field of wireless communication, and in particular, to a method, a system and a competitive fallback method for realizing competition for unauthorized carrier usage rights.

Background technique

Currently, Long Term Evolution (LTE) communication networks are deployed in licensed carriers. With the development of LTE, some companies have proposed "recommending research on LTE deployment in unlicensed carriers", such as Qualcomm in the United States. It is believed that with the rapid growth of data services, in the near future, authorized carriers will not be able to withstand the huge amount of data brought by rapid business growth. Considering that LTE is deployed in an unlicensed carrier to share the data traffic in the authorized carrier, the data volume pressure brought by the service growth can be solved. At the same time, the unlicensed carrier has the following characteristics: on the one hand, since the unlicensed carrier does not need to be purchased, or the carrier resource is zero cost, the unlicensed carrier is free or low-cost; on the other hand, since the individual and the enterprise can participate in the deployment, the device The quotient equipment is also available, so the admission requirements of the unlicensed carrier are low; in addition, when the unlicensed carrier is shared, when multiple different systems are operating or when different operators of the same system are operating, some shared resources may be considered. Way to improve carrier efficiency.

In summary, although LTE deployment has obvious advantages in unlicensed carriers, in the process of deployment, there are still problems: multiple wireless access technologies (cross-communication standards, difficult collaboration, diverse network topologies) and There are many wireless access sites (the number of users is large, the collaboration is difficult, and the centralized management overhead is large). Due to the large number of wireless access technologies, there will be various wireless systems in the unlicensed carrier, which are difficult to coordinate with each other and have serious interference. Therefore, LTE is deployed in unlicensed carriers and still needs to support the regulation of unlicensed carriers. Most countries require the system to support the listening and speaking mechanism when deployed in unlicensed carriers. By listening to the mechanism first, it is possible to avoid interference caused by the simultaneous use of unlicensed carriers between adjacent systems. And the competition back-off mechanism is further introduced, that is, the neighboring system sites (generally the neighboring transmission nodes of the same system) can avoid the interference caused by the neighboring transmission nodes of the same system simultaneously using the unlicensed carriers through the contention back-off mechanism.

For the implementation of the competitive fallback mechanism, if referring to the competitive fallback mechanism in the related art wifi system, multiple adjacent transmission nodes often compete for unlicensed carriers at the same time, and multiple adjacent transmission nodes are not clearly known at the same time. The right to use the unlicensed carrier, so that multiple adjacent transport nodes will use unlicensed carriers to send data to the target station. During the transmission process, due to interference between each other, the target site cannot correctly receive and parse the data, and the target site cannot feed back the acknowledgement message (ACK) information to the sending site, resulting in data transmission failure. At this time, multiple sites will consider There is interference in the channel (there are neighboring transmission nodes using unlicensed carriers at the same time), and the competition for unauthorized carrier usage rights will be re-executed. The competitive fallback mechanism in the Wifi system is briefly described as follows: Each access point (AP) listens to an unlicensed carrier, and when it detects that the unlicensed carrier has a continuous fixed (protocol specified) duration, these APs start. A competitive fallback mechanism is performed to determine which AP obtains the right to use the unlicensed carrier. The maximum size of the contention rewind window in Wifi is 1024 time slots. Each time slot is used as a backoff unit in a contention rewind window, and the time slots (or retracting units) in the contention retract window are numbered from 0. ~1023. Each AP participating in the competitive fallback mechanism randomly generates a value within the size of the competitive fallback window (ie, between 0 and 1023) as its own fallback time point and performs counting. The specific count is to set the initial value of a countdown counter to the value. When the value is decremented by 1, the time goes through a time slot (return unit), before the AP retreat time point arrives (before the counter is 0), if the AP listens If the unlicensed carrier is always idle, the AP obtains the unlicensed carrier usage right and uses the unlicensed carrier to transmit data. When the AP retreats the time point before the counter arrives (before the counter is 0), if the AP listens to the unlicensed carrier, it is always busy. Then, the AP cannot obtain the unlicensed carrier usage right, and ends the unlicensed carrier competition. Obviously, when a plurality of APs randomly generate the same value, the adjacent multiple APs simultaneously use the unlicensed carrier, which causes a large interference.

In summary, for the competition mechanism of LTE deployed in unlicensed carriers, referring to the competition method of the related system, it is inevitable that in the competition process, multiple neighboring transmission nodes simultaneously compete for the use rights of the unlicensed carriers, resulting in simultaneous Collisions between transmission nodes that compete to unlicensed carriers occur, causing channel interference, resulting in a problem of data transmission failure.

Summary of the invention

The following is an overview of the topics detailed in this document. This summary is not intended to limit the claims The scope of protection.

The embodiments of the present invention provide a method and system for competing for non-authorized carrier usage rights, and a method for competing for fallback, so as to solve the problem of how to achieve unfairness of unlicensed carriers, make unlicensed carriers use reasonably, and avoid channel interference caused by contention conflicts. Technical problem.

An embodiment of the present invention provides a method for implementing unlicensed carrier usage rights competition, including:

Each of the transmitting nodes randomly generates a first back-off time point number of each of the first competitive back-off windows;

Each of the transmitting nodes simultaneously listens to the unlicensed carrier in the respective first contention retreat window. Before the first retreat time point number arrives, if the unlicensed carrier is always heard to be idle, the second contention retreat is continued. Unlicensed carrier usage rights competition within the window; if the unlicensed carrier is detected to be busy, the unlicensed carrier usage right competition is stopped;

The transmission node that competes for the unlicensed carrier usage right in the second contention fallback window performs data transmission on the unlicensed carrier.

Optionally, the method further includes: before performing the unlicensed carrier usage right competition in the second contention fallback window,

And transmitting, by the unlicensed carrier, the first signal, when the first retracting time point number arrives before the arrival of the first retracting time point. Indicates that the unlicensed carrier is busy.

Optionally, the transmitting node includes: a base station site, or a cell under the base station site, or a user terminal UE;

The unlicensed carrier usage rights competition in the second contention fallback window includes:

The first backoff time point number of the transmitting node that continues the unlicensed carrier usage right competition in the second contention retreat window plus one or the first backoff time point number plus the first signal transmission duration plus one is used as the a starting number of the back-off unit of the second contention fallback window, to continue the number of the transmitting node that performs the unlicensed carrier usage right competition in the second contention rewind window as its corresponding second back-off time point number ;

Starting from the second back-off point number, starting from the countdown to the start number of the back-off unit of the second competitive fallback window, when the countdown is counted to the start number of the back-off unit of the second competitive fallback window, unauthorized The transmitting node that is idle is acquiring the unlicensed carrier usage right;

Wherein, when the transmission node is a base station site, the number of the transmission node is preset;

When the transmitting node is a cell under the base station site, the number of the transmitting node is a physical ID of the cell;

When the transmitting node is a UE, the number of the transmitting node includes: after the UE belongs to the UE, the physical ID of the virtual cell is the number of the UE, or the station to which the UE belongs is allocated to the UE. The cell radio network temporary identifier C-RNTI is the number of the UE.

Optionally, the starting number of the back-counting unit from the second back-off time point number to the second competitive back-off window includes:

After the countdown to 0 is started from the second backoff time point number, starting with the total number of the transmission nodes that perform the unlicensed carrier usage right competition, and continuing the countdown to the second competitive backoff window The starting number of the unit.

Optionally, the unlicensed carrier usage rights competition in the second contention fallback window includes:

Obtaining the number of neighboring transmission nodes actually deployed by the transmission node or the total number of back-off units in the second contention retreat window,

And when the first backoff time point number of the transmitting node that continues to compete for the unlicensed carrier usage right in the second contention retreat window is greater than the total number of back-off units in the second contention retreat window, a back-off time point number plus a pair of second competitive back-off windows, a total number of rollback units, a starting number of the back-off unit as the second competitive back-off window; or, a second competitive fallback window If the first backoff time point number of the transit node that continues to compete for the unlicensed carrier usage right is less than the total number of backoff units in the second competitive backoff window, the first backoff time point number is incremented by one. a starting number of a fallback unit as the second contention fallback window;

And the neighboring transmission node number of the transmitting node that continues the unlicensed carrier usage right competition in the second contention retreat window is used as the corresponding second backoff time point number, and the countdown to the second contention retreat window is performed. The starting number of the rollback unit, when the countdown counts to the start number of the backoff unit of the second contention fallback window, and the unlicensed carrier obtains the unauthorized carrier use right for the idle transit node;

or,

The first backoff time point number of the transmitting node that continues the unlicensed carrier usage right competition in the second contention fallback window plus the time length of sending the first signal plus one greater than the total in the second competitive backoff window If the number of units is rolled back, the first retraction time point number is added, and the total number of retreating units in the second competition retreat window is taken, and the starting number of the retreating unit as the second competition retreat window is taken. Or, the first backoff time point number of the transmitting node that continues the unlicensed carrier usage right competition in the second contention retreat window plus the time length of transmitting the first signal plus one less than the total backoff unit in the second contention retreat window The number of the first back-off time point number plus the time length of transmitting the first signal plus one, the starting number of the back-off unit as the second contention retreat window;

Forwarding the adjacent transmission node number of each transmission node that continues the unlicensed carrier usage right competition in the second contention fallback window as its corresponding second backoff time point number, and performing a countdown to the second contention retreat window The starting number of the unit is rolled back. When the countdown counts to the starting number of the back-off unit of the second contention retreat window, the unlicensed carrier acquires the unauthorized carrier usage right for the idle transmitting node.

Taking 0 as the starting number of the retreating unit of the second contention retreat window;

Forwarding the adjacent transmission node number of each transmission node that continues the unlicensed carrier usage right competition in the second contention fallback window as its corresponding second backoff time point number, and performing a countdown to the second contention retreat window The starting number of the unit is rolled back. When the countdown counts to the starting number of the back-off unit of the second contention fallback window, the unlicensed carrier acquires the unauthorized carrier usage right for the idle transmitting node.

When the second backoff time point number of the transmitting node that continues the unlicensed carrier usage right competition in the second contention fallback window is smaller than the starting number of the backing unit of the second contention fallback window, the second back After the countdown number starts to count down to 0, it starts with the total number of back-off units in the second competitive fallback window, and continues to count down to the start number of the back-off unit of the second competitive fallback window.

Optionally, the first signal comprises: an occupied signal of the unlicensed carrier, and/or an agreed sequence signal, and/or a reference signal, and/or a synchronization signal;

The first signal transmission duration includes: a back-off unit of one or more contention retreat windows.

On the other hand, the embodiment of the present invention further provides a transmission node that implements competition for unlicensed carrier usage rights, including: a random number unit, a first contention unit, a second contention unit, and a transmission unit;

a random number unit, configured to randomly generate its first backoff time point number in the first contention fallback window;

The first contention unit is configured to simultaneously listen to the unlicensed carrier in the first contention retreat window, and before the arrival of the first retreat time point number, if the unlicensed carrier is always heard to be idle, continue the second competition. Unauthorized carrier usage right competition within the window; if the unlicensed carrier is detected to be busy, the unlicensed carrier usage right competition is stopped;

a second contention unit, configured to compete for unauthorized carrier usage rights in the second contention fallback window;

The transmitting unit is configured to perform data transmission on the unlicensed carrier when competing for obtaining the unlicensed carrier usage right in the second contention retreat window.

Optionally, the transmitting node further includes a notification unit, configured to always detect the unlicensed carrier as idle before the first retreat time point arrives before the non-authorized carrier usage right competition is performed in the second contention retreat window. And transmitting, by using the unlicensed carrier, the first signal when the first retreat time point number arrives, so that other transmitting nodes can detect that the unlicensed carrier is busy;

The first signal includes an occupancy signal of an unlicensed carrier, and/or an agreed sequence signal, and/or a reference signal, and/or a synchronization signal.

Optionally, the transmission node includes: a base station site, or a cell under the base station site, or a user terminal UE;

The second contention unit is set to,

When the non-authorized carrier usage right competition is continued in the second contention retreat window, the first retreat time point number plus one or the first retreat time point number plus the first signal transmission duration plus one is used as the second competition. The starting number of the retreating unit of the rewind window, with its own number as its corresponding second retreat time point number;

Starting from the second back-off point number, starting from the countdown to the start number of the back-off unit of the second competitive back-off window, when the countdown is counted to the start number of the back-off unit of the second contention fallback window, the unlicensed carrier is Get free access to unauthorized carriers when you are free;

When the transmitting node is a base station site, the number of the transmitting node is a preset number;

Optionally, the second contention unit is further configured to

When the second back-off time point number is smaller than the start number of the back-off unit of the second contention retreat window,

Starting from the second backoff time point number and counting down to 0, starting with the total number of the transmitting nodes that compete for the unlicensed carrier usage rights, continuing the countdown to the start of the backoff unit of the second competitive backoff window Numbering;

When the countdown is counted to the start number of the backoff unit of the second contention fallback window, and the unlicensed carrier is idle, the unlicensed carrier usage right is acquired and data transmission is performed.

Optionally, the second contention unit is set to,

Obtaining the number of neighboring transport nodes actually deployed by the transport node or the total number of back-off units in the second competing backoff window,

When the first backoff time point number plus one is greater than the total number of back-off units in the second competitive back-off window, the first back-off time point number is added, and the total number of back-off units in the second competitive back-off window is taken. The starting number of the retreating unit as the second competitive retreat window; or, if the first retreat time point number plus one is less than the total number of retreating units in the second competitive retreat window, the first retreat time is taken The point number plus one is the starting number of the retreating unit of the second competitive retreat window;

The neighboring transmission node number of the transmission node itself in the second contention retreat window is used as its corresponding second backoff time point number, and the starting number of the back-off unit of the second competition back-off window is counted down, when the countdown is counted to The starting number of the back-off unit of the second contention retreat window, and the unlicensed carrier is used for the unlicensed carrier;

or,

Adding the first backoff time point number plus the number of the neighboring transmission nodes greater than the actually deployed transmission node, and taking the first backoff time point number plus a pair of second contention fallback windows The total number of units in the back-off unit is taken as the starting number of the unit of the second competitive back-off window; or the first-time back-off point number plus the length of the first signal is added plus one less than the second competitive back-off window When the total number of units is rolled back, the first back-off time point number is added, and the first signal is sent plus one time, and the starting number of the back-off unit as the second competitive back-off window is obtained;

Taking the adjacent transmission node number of the transmission node as its corresponding second backoff time point number, performing a countdown to the start number of the backoff unit of the second contention retreat window, when the countdown is counted to the second contention retreat window The starting number of the fallback unit and the unlicensed carrier are idle, and the unlicensed carrier usage right is obtained.

Optionally, the second contention unit is set to,

0 is the starting number of the fallback unit of the second competitive fallback window;

Taking the neighboring transmission node number of the transmission node as its corresponding second backoff time point number, performing a countdown to the start number of the backoff unit of the second contention retreat window, when the countdown counts back to the second contention retreat window The starting number of the retiring unit. When the unlicensed carrier is idle, the unlicensed carrier usage right is obtained.

Optionally, the second contention unit is further configured to

When the second backoff time point number of the transit node is smaller than the start number of the backoff unit of the second contention fallback window,

After the countdown to 0 is started from the second backoff time point number, starting with the total number of back-off unit numbers in the second contention retreat window, and continuing the countdown to the start number of the back-off unit of the second competition retreat window;

When the countdown is counted to the start number of the backoff unit of the second contention fallback window, and the unlicensed carrier is idle, the unlicensed carrier use right is acquired.

In a further aspect, the embodiment of the present invention further provides a competitive backoff method, where the transit node divides the time direction into a first phase, a second phase, and a third phase;

The first phase and the third phase are composed of several time units, and the time units of the first phase, the second phase and the third phase are numbered;

The transmitting node performs interception in the first phase; the first signal is sent in the second phase by the transmitting node in the first phase, and the interception is continued in the third phase; and the contention rollback is completed through the transport node in the third phase;

The first phase, the second phase, and the third phase are continuous in time, each phase lasting for a certain length of time.

Optionally, the first phase is a first contention fallback window, and the third phase is a second contention fallback window.

Optionally, the start number of the time unit number of the third stage includes: adding a first backoff time point number of the first node or a first back time point number of the first stage plus Send the first signal plus one more time; or,

When the first backoff time point number of the transmission node in the third stage is greater than the total value of the time unit included in the third stage, the start number of the time unit number of the third stage includes: taking the first The retraction time point number plus a pair of the total number of time units included in the third stage is taken; or

When the first backoff time point number of the transmission node in the third stage is greater than the total value of the time unit included in the third stage, the start number of the time unit number of the third stage includes: Retract the time point number plus one; or,

When the first back-off time point number of the transmission node in the third stage is greater than the total value of the time unit included in the third stage, the first back-off time point number is added with a pair of time unit numbers included in the third stage. The value after modulo is used as the starting number of the time unit number of the third stage; or,

When the first backoff time point number of the transmission node in the third stage is greater than or equal to the total value of the time unit included in the third stage, the first backoff time point number is incremented by one as the time unit of the third stage. The starting number of the number; or,

The start number of the time unit number of the third stage is 0.

Optionally, when the starting number of the time unit number of the third stage is the first backing time point number plus one or the first backing time point number plus the sending of the first signal duration plus one, the third stage The second backoff time point number is the number of the transmission node that performs the unlicensed carrier usage right competition in the third stage; the loop number of the third stage is the total value of the time unit included in the third stage;

When the start number of the time unit number of the third stage is the value of the first back-off time point number plus the total number of time units included in the third stage, the third stage is continued. The adjacent transmission node number of the transmission node that is not authorized by the carrier usage right is used as its corresponding second backoff time point number; the loop number of the third stage is the total value of the time unit included in the third stage;

When the first backoff time point number of the transmission node in the third stage is greater than the total value of the time unit included in the third stage, and the first backoff time point number is incremented by one, the unlicensed carrier is continued in the third stage. The neighboring transmission node number of each transmission node that uses the right to compete as its corresponding second backoff time point number; the loop number of the third stage is the total number of time units included in the third stage;

When 0 is used as the starting number of the time unit number of the third stage, the neighboring transmission node number of each transmitting node that continues the unlicensed carrier usage right competition in the third stage is taken as its corresponding second backoff time point number. ;

When the first retracted time point number plus a pair of values of the total number of time units included in the third stage is used as the starting number of the time unit number of the third stage, the second retreat time point of the third stage is used. The number of the transmission node numbered as the third phase for the unlicensed carrier usage right competition; the third phase of the cycle number is the total number of time units included in the third phase;

The first back-off time point number of the transmission node in the third stage is incremented by one or less than or equal to the total number of time units included in the third stage, and the first back-off time point number is incremented by one as the time unit number of the third stage. The starting number of the third stage is the number of the transmitting node that competes for the unlicensed carrier usage right in the third stage; the number of the third stage is the total number of time units included in the third stage. Value.

Optionally, the method further includes: when the second backoff time point number of the third stage is smaller than the start number of the time unit number of the third stage,

After counting down to 0 from the second back-off time point number, starting from the cycle number of the third stage, the countdown to the start number of the time unit number of the third stage is continued;

When the second backoff time point number of the third stage is greater than or equal to the start number of the time unit number of the third stage, the transmission node directly counts down.

Optionally, the first phase, the second phase, and the third phase are consecutively included in time: the time unit number of the first phase and the time unit number of the third phase are consecutive.

Optionally, when there are also several time units in the second phase, the first phase, the second phase, and the third phase are consecutively included in time: a time unit number of the first phase and a time unit number of the second phase Continuously, the time unit number of the third stage is continuous with the time number of the second stage.

Optionally, the numbering of the time units of the first phase and the third phase includes: independently numbering the time units of the first phase, and independently numbering the time units of the third phase.

Optionally, when the transmitting node performs a contention rollback in the first phase and the third phase, the passing includes: before the first backoff time point number of the transmission phase arrives or the transit node is from the first backoff time When the point number countdown counter counts back to 0, the transmission phase listening for unauthorized carrier usage rights is always idle.

Optionally, the contention fallback method is applied to the use right competition of the unlicensed carrier, and the unlicensed carrier use right is obtained through the third stage transmission node;

The transmitting node that passes through the third stage is the starting number of the time unit number of the third phase, and listens to the transmitting node whose unlicensed carrier is always idle.

The embodiment of the invention further provides a computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions are used to execute the above method.

Compared with the related art, the technical solution provided by the embodiment of the present invention includes: each transmitting node randomly generates a first backoff time point number of each of the first contention retreat windows; each of the transmitting nodes is in the first of each In the competition fallback window, the unlicensed carrier is simultaneously intercepted, and the unlicensed carrier usage right competition in the second contention retreat window is continued if the unlicensed carrier is always idle before the arrival of the first retreat time point number. If the unlicensed carrier is detected to be busy, the unlicensed carrier usage right competition is stopped; the transmitting node that competes for obtaining the unlicensed carrier usage right in the second contention retreat window performs data transmission on the unlicensed carrier. In the embodiment of the present invention, the transmitting node competes for the unlicensed carrier usage rights in the first contention time window and the second contention time window, so that the use rights of the unlicensed carrier may belong to only one transmission node, thereby avoiding simultaneous competition of multiple transmission nodes. The collision occurs to the unlicensed carrier usage right, causing channel interference, resulting in data transmission failure, so that the competition of the unlicensed carrier usage rights is fair and reasonable, and the unlicensed carrier is reasonably utilized.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF abstract

1 is a flowchart of a method for implementing unlicensed carrier usage right contention according to an embodiment of the present invention;

2 is a structural block diagram of a transmission node that implements competition for unauthorized carrier usage rights according to an embodiment of the present invention;

FIG. 3 is a flowchart of a method for competing for unlicensed carrier usage rights according to an embodiment of the present invention.

Embodiments of the invention

Embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other.

1 is a flowchart of a method for implementing unlicensed carrier usage right competition according to an embodiment of the present invention. As shown in FIG. 1, the method includes:

Step 100: Each transmission node randomly generates a first backoff time point number of each of the first contention retreat windows. Here, the first contention fallback window corresponds to the first phase of the unlicensed carrier usage right competition.

Step 101: Each transmitting node simultaneously listens to the unlicensed carrier in the first contention retreat window. Before the first retreat time point arrives, if the unlicensed carrier is always heard to be idle, continue to the second. Unlicensed carrier usage rights competition in the competition fallback window; if the unlicensed carrier is detected to be busy, the unlicensed carrier usage right competition is stopped;

It should be noted that the starting number of the back-off unit of the first competitive retreat window is not set, so the default setting is 0. Each of the transmitting nodes simultaneously listens to the unlicensed carrier in the first contention retreat window, that is, in the first contention retreat window, starting from the first retreat time point number and counting down to 0, while listening Unlicensed carrier.

The first backoff time point number of the transmitting node that continues the unlicensed carrier usage right competition in the second contention retreat window plus one or the first backoff time point number plus the first signal transmission duration plus one is used as the Determining a starting number of a back-off unit of the second contention fallback window, to continue the number of the transmitting node that performs the unlicensed carrier usage right competition in the second contention rewind window as its corresponding second back-off time Point number

Starting from the second back-off point number, starting from the countdown to the start number of the back-off unit of the second competitive fallback window, when the countdown is counted to the start number of the back-off unit of the second competitive fallback window, unauthorized The transmitting node that is idle is acquiring the unauthorized carrier usage right.

The transmission node includes: a base station site, or a cell under the base station site, or a user terminal UE;

When the transmitting node is a base station site, the number of the transmitting node is preset;

When the transmitting node is a cell under the base station site, the number of the transmitting node is the physical ID of the cell;

When the transmission node is a UE, the number of the transmission node includes: when the adjacency node of the transmission node configures the virtual cell physical ID for the transmission node, the physical ID of the virtual cell is the number of the transmission node; or, the transmission is performed by the belonging station. The cell radio network temporary identifier (C-RNTI) allocated by the node is the number of the transmission node.

It should be noted that the number of the transmission node that competes for the unlicensed carrier usage right here refers to the number information when the network is formed, and is generally set according to the number of transmission nodes in the network, which is a conventional incrementally arranged number. In addition, the fallback time point number is the starting point of the countdown of the competition fallback window, and the start number of the fallback unit is the fallback termination point of the competitive fallback window.

Optionally, the second backoff time point number of the transit node that continues the non-authorized carrier usage right competition in the second contention fallback window is smaller than the start number of the backoff unit of the second contention fallback window. Time,

The starting number of the back-counting unit from the second back-off time point number to the second competitive back-off window includes:

Starting from the second back-off time point number and counting down to 0, starting with the total number of the transmitting nodes that perform the unlicensed carrier usage right competition, and continuing the countdown to the back-off unit of the second competitive back-off window Start number.

And when the first backoff time point number of the transmitting node that continues the unlicensed carrier usage right competition in the second contention retreat window is greater than the total number of back-off units in the second contention retreat window, The first back-off time point number plus a pair of second competitive back-off windows, the total number of units of the back-off unit, the starting number of the unit of the back-off unit of the second contention retreat window; or, continue the second competition If the number of the first backoff time point of the transmission node that performs the unlicensed carrier usage right competition in the fallback window is less than the total number of the backoff units in the second contention retreat window, the first backoff time point number is added. 1. The starting number of the retreating unit as the second competitive retreat window;

or,

The first backoff time point number of the transmitting node that continues the unlicensed carrier usage right competition in the second contention retreat window plus the time length of sending the first signal plus one is greater than the total backoff in the second contention retreat window For the number of units, the first retraction time point number is added, and the total number of retreating units in the second competition retreat window is taken as the starting number of the retreating unit as the second competition retreat window; or, continue The first back-off time point number of the transmitting node that performs the unlicensed carrier usage right competition in the second contention retreat window plus the time length of transmitting the first signal plus one less than the total number of back-off units in the second contention retreat window, The first back-off time point number plus the time length of transmitting the first signal plus one, the starting number of the back-off unit as the second contention retreat window;

Forwarding the adjacent transmission node number of each transmission node that continues the unlicensed carrier usage right competition in the second contention fallback window as its corresponding second backoff time point number, and performing a countdown to the second The starting number of the back-off unit of the competition fallback window. When the countdown counts to the starting number of the back-off unit of the second contention fallback window, the unlicensed carrier acquires the unauthorized carrier usage right for the idle transmitting node.

When the second backoff time point number of the transit node that continues the unlicensed carrier usage right competition in the second contention fallback window is smaller than the start number of the backoff unit of the second contention fallback window,

Starting from the second back-off time point number and counting down to 0, starting with the total number of back-off unit numbers in the second contention retreat window, continuing the countdown to the start of the second competitive back-off window Numbering.

In this step, before the non-authorized carrier usage right competition is performed in the second contention retreat window, the method in the embodiment of the present invention further includes: the first retracting time point number arrives before the interception of the transmission node that the unlicensed carrier is always idle. When the first retreat point number arrives, the first signal is sent using the unlicensed carrier, so that other transmitting nodes can detect that the unlicensed carrier is busy.

Sending the first signal is essentially the second phase of unlicensed carrier usage rights competition.

The second contention fallback window is the third stage of unlicensed carrier usage rights competition.

The first signal includes an occupancy signal of the unlicensed carrier, and/or an agreed sequence signal, and/or a reference signal, and/or a synchronization signal.

The length of the first signal sent includes: a back-off unit of one or more competing back-off windows.

Step 102: Compete in a second contention retreat window to obtain a transmission node that obtains an unlicensed carrier usage right, and perform data transmission on the unlicensed carrier.

The transmission node includes: a base station station, or a cell under the base station site, or a user terminal UE.

It should be noted that in the related art, each transmission node in the network cannot implement interaction, and the use of the unlicensed carrier is extremely high in the efficiency of the allocation process, and cannot be judged and compared through the interaction setting, so The way to compete for the retreat window, the competition for the right to use.

In the embodiment of the present invention, the transmitting node competes for the unlicensed carrier usage rights in the first contention time window and the second contention time window, so that the use rights of the unlicensed carrier may belong to only one transmission node, thereby avoiding simultaneous competition of multiple transmission nodes. Collision to unauthorized carrier usage rights, causing channel interference, resulting in data transmission failure, thereby making the competition of unauthorized carrier usage rights fair and reasonable, unlicensed carrier Get a reasonable use.

2 is a structural block diagram of a transmission node that implements competition for unlicensed carrier usage rights according to an embodiment of the present invention. As shown in FIG. 2, the method includes: a random number unit, a first contention unit, a second contention unit, and a transmission unit;

The transmitting node of the embodiment of the present invention further includes a notification unit, configured to detect that the unlicensed carrier is idle before the first retreat time point arrives before the non-authorized carrier usage right competition is performed in the second contention retreat window. Then, when the first retreat time point number arrives, the first signal is sent by using the unlicensed carrier, so that other transmission nodes can detect that the unlicensed carrier is busy;

The second contention unit is set to,

Starting from the second back-off point number, starting from the countdown to the back-off unit of the second competitive back-off window The initial number, when the countdown counts to the start number of the backoff unit of the second contention fallback window, and the unlicensed carrier is idle, the unlicensed carrier use right is acquired;

When the transmission node is a base station site, the number of the transmission node is a preset number;

When the transmitting node is the UE, the number of the transmitting node includes: the location of the physical parameter of the virtual cell as the transmitting node after the physical station configures the physical ID of the virtual cell; or the cell allocated by the associated station as the transmitting node The Radio Network Temporary Identity (C-RNTI) is the number of the transmitting node.

The second contention unit is also set to,

When the second back-off time point number is smaller than the start number of the back-off unit of the second competitive fallback window,

After the countdown to 0 is started from the second backoff time point number, the number of the total number of the transmission nodes that compete for the unlicensed carrier usage rights is started, and the countdown to the start number of the backoff unit of the second contention fallback window is continued;

The second contention unit is set to,

The neighboring transmission node number of the transmission node itself in the second contention retreat window is used as its corresponding second backoff time point number, and the starting number of the back-off unit of the second competition back-off window is counted down, when the countdown is counted to The starting number of the back-off unit of the second contention retreat window, and the unlicensed carrier is used to obtain the unlicensed carrier usage right; or

The first backoff time point number plus the time length of sending the first signal plus one transmission greater than the actual deployment The number of the neighboring transit nodes of the node, taking the first backoff time point number plus a pair of second competitive backoff windows, the total number of back-off units, and the starting number of the back-off unit as the second competitive back-off window; Or, the first back-off time point number plus the first signal length plus one is less than the total number of back-off units in the second contention retreat window, and the first back-off time point number plus the first signal duration is added plus one. The starting number of the retreating unit of the second competitive retreat window;

Taking the neighboring transmission node number of the transmission node as its corresponding second backoff time point number, performing a countdown to the start number of the backoff unit of the second contention retreat window, when the countdown counts back to the second contention retreat window When the starting number of the retiring unit and the unlicensed carrier are idle, the unlicensed carrier usage right is obtained.

The second contention unit is set to,

The second contention unit is further configured to: when the second backoff time point number of the transit node is smaller than the start number of the backoff unit of the second contention fallback window,

An embodiment of the present invention further provides a competitive backoff method, where a transit node divides a time direction into a first phase, a second phase, and a third phase;

The transmitting node performs interception in the first phase; the transit node in the first phase sends in the second phase Sending the first signal, and continuing to perform the interception in the third phase; completing the competitive fallback through the transport node of the third phase;

It should be noted that the completion of the competition back-off refers to obtaining the right to use resources preferentially in the process of competitive fallback through the third-stage transmission node.

The first phase, the second phase, and the third phase are continuous in time, and each phase lasts for a certain period of time.

The first phase is a first competitive fallback window, and the third phase is a second competitive fallback window.

The starting number of the time unit number of the third stage includes: the first back-off time point number of the transmitting node through the first stage plus one or the first back-off time point number of the first stage plus the length of the first signal sent. Add one; or,

When the first backoff time point number of the transmission node in the third stage is greater than the total value of the time unit included in the third stage, the first backoff time point number is added and the total number of time units included in the third stage is added. The value after the numerical modulo is used as the starting number of the time unit number of the third stage; or,

The start number of the time unit number of the third stage is 0.

When the start number of the time unit number of the third stage is the first retreat time point number plus one or the first retreat time point number plus the first signal transmission time plus one, the second retreat moment of the third stage The point number is the number of the transmission node that competes for the unlicensed carrier usage right in the third stage; the cycle number of the third stage is the total value of the time unit included in the third stage;

When the start number of the time unit number of the third stage is, take the first retreat time point number When the value of the total number of time units included in the third phase is modulo, the neighboring transmission node number of the transmitting node that continues the unlicensed carrier usage right competition in the third phase is used as its corresponding second backoff time point number; The cycle number of the third stage is the total number of time units included in the third stage;

When the first backoff time point number of the third stage transmission node is incremented by less than the total number of time units included in the third stage, and the first backoff time point number is incremented by one, the third stage continues to use the unlicensed carrier use right. The neighboring transmission node number of each transmission node that competes as its corresponding second backoff time point number; the loop number of the third stage is the total number of time units included in the third stage;

When the second retracting time point number of the third stage is smaller than the starting number of the time unit number of the third stage, the method of the embodiment of the present invention further includes:

The first phase, the second phase, and the third phase are consecutively included in time: the time unit number of the first phase and the time unit number of the third phase are consecutive.

When there are also several time units in the second phase, the first phase, the second phase and the third phase Continuously includes in time: the time unit number of the first stage is continuous with the time unit number of the second stage, and the time unit number of the third stage is continuous with the time number of the second stage.

The numbering of time units in the first and third phases includes the independent numbering of the time units of the first phase and the independent numbering of the time units of the third phase.

When the transmitting node performs the contention rollback in the first phase and the third phase, the method includes: when the first backoff time point number of the transmission phase arrives or the transmitting node counts down from the first backoff time point countdown counter to 0 Previously, the transmission phase listening for unauthorized carrier usage rights was always idle.

The competitive fallback method is applied to the use right competition of the unlicensed carrier, and the unlicensed carrier use right is obtained through the third stage transmission node;

Through the transmission node of the third stage, for the start number of the time unit number of the third stage, the transmission node whose unlicensed carrier is always idle is detected.

The embodiments of the present invention are described in detail below by way of specific embodiments. The embodiments are not intended to limit the protection of the present invention. The following embodiments all take a base station site as an example.

Example 1

Suppose there are 10 sites (numbered as Site 1 to Site 10) and compete for the right to use the same unlicensed carrier. Assume that there are 512 time units in the first phase of the competitive backoff window, numbered from 0 to 511. The 10 sites randomly generate the first backoff time point numbers of the respective first contention retreat windows from 0 to 511, respectively, and assume that the stations 1 to 10 respectively randomly generate numbers 50, 200, 320, 404, 150, 180, 210, 50, 302, 311. According to the process of performing competition, the number randomly generated by station 1 and station 8 is 50 and the smallest, so when station 1 and station 8 count down from the first back-off point number to 0, the intercepted unlicensed carrier is always empty. Therefore, the site 1 and the site 8 are the unauthorised use rights competitions that successfully pass the first contention fallback window at the same time. When the first backoff time point number is 0, the first signal is sent by using the unlicensed carrier, and the first signal sends at least the occupied signal. At this point, other sites will hear that the unlicensed carrier is busy, and other sites stop the competition.

Suppose that the sending time of the signal sent by station 1 and station 8 is 2 back-off time units, then the second The starting number of the retracting unit of the competition retreat window is the first retreat time point number plus two retreat time units, that is, 53. In this embodiment, the second retreat time of the second competitive retreat window is assumed. The point number is the number of the node, (assuming the cell number is 504, the corresponding value is 0 to 503). Assuming that the numbers of Site 1 and Site 8 are 105 and 231, respectively, the numbers 105 and 231 of Site 1 and Site 8 are respectively used as the second backoff time point number, and the countdown is counted to 53, and the uncounted carrier is performed during the countdown process. Listening, when the countdown to 53 is that the unlicensed carrier is empty, then the station performs data transmission; when the countdown to 53 detects that the unlicensed carrier is busy, the station stops the competition. . In this embodiment, the station 1 will first fall back to 53, so the station 1 obtains the unauthorized carrier usage right, and the station 8 will stop the competition. If the number of station 1 is 10, that is, less than 53, then the station needs to count down according to the following principles, 10, 9, 8, 7, . . . 0, 503 (total number of numbers), 502, 501...55, 54, 53 That is, the cycle counts down.

Example 2

Suppose there are 10 sites (numbered as Site 1 to Site 10) and compete for the right to use the same unlicensed carrier. Assume that there are 512 time units in the first phase of the competitive backoff window, numbered from 0 to 511. The 10 sites randomly generate the first backoff time point numbers of the respective first contention retreat windows from 0 to 511, respectively, and assume that the stations 1 to 10 respectively randomly generate numbers 50, 200, 320, 404, 150, 180, 210, 50, 302, 311. According to the process of performing competition, the number randomly generated by station 1 and station 8 is 50 and the smallest, so when station 1 and station 8 count down from the first back-off point number to 0, the intercepted unlicensed carrier is always empty. Therefore, the site 1 and the site 8 are the unauthorised use rights competitions that successfully pass the first contention fallback window at the same time. When the first backoff time point counts down to 0, the first signal is sent on the unlicensed carrier, and at least the occupied signal is included. At this point, other sites will hear that the unlicensed carrier is busy, and other sites stop the competition.

The starting number of the retracting unit of the second contention retracting window is the number of the first retreat time point plus 1, which is 51. In this embodiment, the second retracting time point of the second contention retracting window is assumed to be a node. The number, (assuming the cell number is 504, the corresponding value is 0 to 503). Assuming that the numbers of station 1 and station 8 are 105 and 231, respectively, the numbers 105 and 231 of station 1 and station 8 are respectively used as the second backoff time point number, and the countdown is counted to 51, and the unauthenticated carrier is performed during the countdown process. Listening, when the countdown is 51, the interception result is that the unlicensed carrier is empty, then the station performs data transmission; when the uncounted carrier is busy before the countdown to 51, the station stops the competition. . This implementation In the example, Site 1 will fall back to 51 first, so Site 1 will gain unauthorized carrier usage rights, and Site 8 will stop this competition. If the number of station 1 is 10, that is, less than 51, the station needs to count down according to the following principles: 10, 9, 8, 7, . . . 0, 503, 502, 501...55, 54, 53 .

Example 3

Suppose there are 10 sites (numbered as Site 1 to Site 10) and compete for the right to use the same unlicensed carrier. Assume that there are 512 time units in the first phase of the competitive backoff window, numbered from 0 to 511. The 10 sites randomly generate the first backoff time point numbers of the respective first contention retreat windows from 0 to 511, respectively, and assume that the stations 1 to 10 respectively randomly generate numbers 50, 200, 320, 404, 150, 180, 210, 50, 302, 311. According to the process of performing competition, Site 1 and Site 8 are randomly generated with a number of 50 and the smallest, so when Site 1 and Site 8 count down from the first backoff point number to 0, the intercepted unlicensed carrier is always empty. Therefore, the site 1 and the site 8 are the unauthorised use rights competitions that successfully pass the first contention fallback window at the same time. When the first backoff time point number starts counting down to 0, the first signal is sent through the unlicensed carrier, and at least the occupied signal is sent. At this time, other sites will hear that the unlicensed carrier is busy, and other sites stop the competition.

Assume that the actual deployment target number of the site is the time unit included in the contention backoff time of the second contention fallback window, which is assumed to be 30. The third stage start number is determined as follows: when the first back-off time point number of the station 1 and the station 8 plus the transmission time length plus 1 is greater than the competition back-off time 30, then for the modulo 30, the obtained value is used as the back-off unit. The starting number, when less than 30, is directly used as the starting number of the retreating unit. According to the above rules, the starting number of the fallback unit of this embodiment is 23 (53 mod 30=23). Assume that the number of Site 1 and Site 8 (the number of adjacent transit nodes corresponding to the number of neighboring transit nodes) is 15 and 28. Then, Site 1 and Site 8 count down from 15 and 28 to 23, respectively, and listen to the unlicensed carrier during the countdown process. When the countdown to 23, the interception result is that the unlicensed carrier is empty, then the station sends a signal. When the undetected carrier is busy before counting down to 23, the station stops the competition. In this embodiment, the station 8 will first fall back to 23, so the station 8 obtains the unauthorized carrier usage right, and the station 1 will stop the competition.

In this embodiment, the number of the station 1 is 15 and less than 23, so the countdown process is: 15, 14, 13...0, 29, 28, 27...25, 24, 23, that is, the loop countdown.

Example 4

Suppose there are 10 sites (numbered as Site 1 to Site 10) and compete for the right to use the same unlicensed carrier. Assume that there are 512 time units in the first phase of the competitive backoff window, numbered from 0 to 511. The 10 sites randomly generate the first backoff time point numbers of the respective first contention retreat windows from 0 to 511, respectively, and assume that the stations 1 to 10 respectively randomly generate numbers 50, 200, 320, 404, 150, 180, 210, 50, 302, 311. According to the process of performing the competition, Site 1 and Site 8 randomly generate the number 50 and the smallest, so when Site 1 and Site 8 go from the first backoff time point to 0, the intercepted unlicensed carrier is always empty, so Site 1 And the site 8 is the unauthorised use right competition that successfully passes through the first contention fallback window at the same time. When the first backoff time point counts down to 0, the first signal containing at least the occupied signal is sent, and other sites will be heard. The unlicensed carrier is busy, and other sites stop this competition.

Assume that the actual deployment target number of the site is the time unit included in the contention backoff time of the second contention fallback window, which is assumed to be 30. The third stage start number is determined as follows: when the first backoff time point number of Site 1 and Site 8 is greater than 1 and the competitive backoff time is 30, then for 30 modulo, the obtained value is used as the starting number of the backoff unit. When it is less than 30, it is directly used as the starting number of the back unit. According to the above rules, the starting number of the retracting unit of this embodiment is 21 (51 mod 30 = 21). Assume that the number of Site 1 and Site 8 (the number of adjacent transit nodes corresponding to the number of neighboring transit nodes) is 15 and 28. Then, the station 1 and the station 8 count down from 15 and 28 to 23, respectively, and listen to the unlicensed carrier during the countdown process. When the countdown to 21, the interception result is that the unlicensed carrier is empty, then the station sends a signal. When the undetected carrier is busy before counting down to 21, the station stops the competition. In this embodiment, the station 8 will first fall back to 21, so the station 8 obtains the unauthorized carrier usage right, and the station 1 will stop the competition.

In this embodiment, the number of the station 1 is 15 and less than 21, so the countdown process is: 15, 14, 13...0, 29, 28, 27...23, 22, 21, that is, the loop countdown.

Example 5

Suppose there are 10 sites (numbered as Site 1 to Site 10) and compete for the right to use the same unlicensed carrier. Assume that there are 512 time units in the first phase of the competitive backoff window, numbered from 0 to 511. The 10 sites randomly generate the first backoff time point numbers of the respective first contention retreat windows from 0 to 511, respectively, and assume that the stations 1 to 10 respectively randomly generate numbers 50, 200, 320, 404, 150, 180, 210, 50, 302, 311. In accordance with the process of performing competition, the station Point 1 and station 8 are randomly generated with a number of 50 and the smallest, so when Site 1 and Site 8 count down from the first backoff point number to 0, the intercepted unlicensed carrier is always empty, so Site 1 and Site 8 It is the unlicensed use right competition that successfully passes the first contention retreat window at the same time. When the first backoff time point is 0, the first signal containing at least the occupied signal is sent, and other stations will detect that the unlicensed carrier is busy. Other sites stop this competition.

The second contention fallback window and the first contention fallback window are independent of each other, that is, the starting number of the back unit of the second competitive pushback window is independent of the first contention rewind window. This embodiment assumes that the number of neighbors in the actual deployment according to the site is the time unit included in the contention backoff time of the second contention fallback window, which is assumed to be 30. Assume that the starting number of the back-off unit of the second competitive pushback window is 0, assuming that the adjacent transit node numbers of Site 1 and Site 8 are 15 and 28. Then, station 1 and station 8 count down from 15 and 28 to 0 respectively, and listen to the unlicensed carrier during the countdown process. When the countdown to 0, the interception result is that the unlicensed carrier is empty, then the station sends a signal. The site stops the competition when it detects that the unlicensed carrier is busy before counting down to zero. Specifically, in this embodiment, the station 1 will first fall back to 0, so the station 1 obtains the unauthorized carrier usage right, and the station 8 will stop the competition.

FIG. 3 is a flowchart of a method for implementing unlicensed carrier usage right competition according to an embodiment of the present invention. As shown in FIG. 3, the method includes:

The station (including the base station, or the UE) performs the contention of the unlicensed carrier usage rights in the first contention fallback window (temporarily referred to as the first phase). When the station contends to the unlicensed carrier usage right in the first contention fallback window, the station starts to send the first signal (notification phase or second phase), and after the first signal is sent, the station enters the second contention retreat window (also It is the third stage) to perform unlicensed carrier usage rights competition and perform competition again, including one or more of the following:

In the first mode, the station calculates the second backoff time point number in the second contention fallback window according to its own number (ID), and performs a contention process to determine whether it is the right to use the unauthorized carrier alone (or eventually). ;or,

In mode 2, the station determines the second backoff time point number in the second contention fallback window according to the number used in the second second competition fallback window, and performs a contention process to determine whether it is independent (or eventually). Authorized carrier usage rights.

Optionally, the site calculates according to its own ID: the ID may be predefined or configured to the site. Optionally, when the cell subordinate to the site participates in the competition, the physical ID of the cell may be used; when the site is a UE, the UE needs to receive the virtual cell physical ID configured by the site in advance, and the UE uses the virtual cell physics. ID; or the UE uses the C-RNTI assigned by the station.

Optionally, the station performs the competition of the unlicensed carrier usage rights in the first contention retreat window, including: the station uses the first retraction time point number in the first contention rewind window to be randomly generated (adjacent retreat time point) The corresponding time difference is a back-off unit. Before the first retraction time point number arrives or the countdown is 0, the station always performs interception for the unlicensed carrier. If the interception result is that the unlicensed carrier is busy (refers to If there is a signal transmission in the carrier, and the energy value of the signal is higher than the set threshold, it is busy; if the energy value of the signal is lower than the set threshold, it is idle), then the station suspends the competition back and pauses the counter countdown. The site believes that it has failed to compete for unauthorized carrier usage rights. If the interception result is that the unlicensed carrier is idle, the station considers itself to compete for the unlicensed carrier usage right, but the station at this time may compete with the neighboring transmission node for the right to use the unlicensed carrier at the same time. This is because the contention retreat window of the adjacent transmission node competing for the unlicensed carrier usage right is time-aligned, and the generation range of the retreat time point is the same or partially overlapping, and the first retreat time point is randomly generated by the station. Therefore, it is possible that multiple sites generate the same fallback time point, so that during the execution of the competition, the countdown to 0 is simultaneously counted, and the two sites simultaneously find that the unlicensed carrier is idle.

Optionally, the station starts to send the first signal, including: the station that obtains the unlicensed carrier usage right in the first contention fallback window starts to send the first signal (including at least the occupied signal) when the first backoff time point number arrives. The duration of the continuous transmission is agreed in advance. A station that does not obtain unauthorized carrier usage rights in the first contention fallback window does not transmit a signal. This is mainly to shield the sites that are still performing the competition. After the station that obtains the right to use the signal, the other stations that are still performing the competition will hear the signal in the unlicensed carrier, thus obtaining the unlicensed carrier. Busy, thus suspending the ongoing competition.

Optionally, the station starts to send the first signal, and the duration of the continuous transmission is at least one back-off unit, and preferably one or two back-off units are continuously sent. The back unit length can be equal to the back unit in the first competitive fallback window.

The first signal may be a channel signal. In the embodiment of the present invention, the channel is designed to: after the station preempts the unauthorized use right, the channel is sent to indicate the preemption to the neighboring stations. When the unlicensed carrier is reached, the signal may include the duration information of the site occupying the unlicensed carrier usage right.

Optionally, the site calculates a second backoff time in the second contention fallback window according to the ID, including: the number of the backoff units included in the second contention fallback window is equal to the total number of site IDs, such that each The site can uniquely determine its own second fallback time point number in the competitive fallback window according to its own ID value, so that when the competition is performed in the second competitive fallback window, the site will not be generated to compete at the same time. The case of authorizing carrier usage rights.

Optionally, the station determines, according to the number used in the second contention retreat window in advance, the second backoff time number in the second contention retreat window, including: according to a signal in the vicinity of each other that can be intercepted by each other. The number of sites that determine the window length of a largest second competitive back-off window. For example, when a site is deployed, the number of sites participating in the competition in the area can be counted according to the actual deployment situation. Referring to the number of sites, a reasonable window length is set for the site in the area as a second contention fallback window. Generally, the number of back-off units included in the second contention fallback window is greater than the maximum number of stations in the statistics. In this way, when each station in the area performs competition in the second contention fallback window, each station can uniquely correspond to a second backoff time point. For example, the maximum number of neighboring transmission nodes of each station in the area is 30, and then at least the second contention retreat window includes a back-off unit of 30 (can be set to 50 to prevent the increase of subsequent stations). The number of each site in the area is numbered from 1 to 30 (0 to 29 is OK, the principle is the same, the same below). Note that the station numbers that can hear signals are different. When the site competes, each site in the second contention fallback window uses the number as the second backoff time point in the second contention fallback window.

The starting number of the fallback unit in the second contention retreat window: the number corresponding to the time point of the site retreating in the first contention retreat window; or the first retreat time of the station in the first contention retreat window The number of the point number + the number of the second-stage retreat unit; or the number corresponding to the time point of the site retreating in the first competition retreat window for 30 (the total number of retreat units of the second competition retreat window) The value obtained after the simulation (this method is used when the first-stage competition window includes the retreat unit greater than 30, the same below); or the first retraction time point number + second for the station in the first competitive retreat window The number after the rollback unit of the phase (sending the first signal phase) is the value obtained after modulo 30 (the total number of retreat units of the second competition retreat window); or 1. The different numbering methods of the retreating units in the second competitive retreat window directly affect the fairness of the third stage competition. The numbering mode (except for the mode of 1) in the embodiment of the present invention can achieve a randomized effect, thereby ensuring the fairness of the third stage competition. The last way is also Can be used, but fairness is not guaranteed.

When a site can process through a total of three phases, the site can be the only one to obtain the use rights of the unlicensed carrier, thereby avoiding the occurrence of contention conflicts and improving the efficiency of the unlicensed carrier.

The embodiment of the present invention simultaneously proposes an unlicensed carrier competition mechanism, and the mechanism includes the following composition structure. A site (which may also be a UE, generally referring to each class of nodes participating in the competition) divides the time direction into a first phase, a second phase, and a third phase. The first, second, and third phases are continuous in time, and the duration of each phase is fixed or configurable. The first phase and the third phase are each composed of several time units, and the time units of each phase are numbered. The station performs the interception in the first phase, successfully transmits the signal in the second phase through the site of the first phase, and performs the interception in the third phase, successfully passes the site of the third phase, and finally obtains the use of the unlicensed carrier. With this kind of competition mechanism, the first stage is used for each participating competition site to maintain the randomness of competition, and the duration of the first phase is changed, that is, in the first stage, when a station starts to send signals, It means that the end of the first phase has entered the second phase.

Optionally, the time unit number in the first phase is continuous with the time unit number in the third phase. In this case, the number of the second stage is excluded, so that the duration of the second stage of transmitting the signal can be freely configured or designed, and is not limited by the unit length of the first stage or the third stage. The role of the second phase is to stop the competition in the first phase of the competition and not reach the first retreat point, so that the number of sites entering the third phase is greatly reduced, thus making the third phase of the competition fall back. The duration of the window can be greatly shortened, thereby saving time resources; the other role of the second phase is also to save time resources in order to terminate the first phase of the process in time.

Optionally, if there are several time units in the design phase in the second stage, the time unit number in the first stage is consecutive with the time unit number in the second stage, and the time unit number in the third stage is in the second stage. The time unit number is continuous.

The time unit number of the third stage mentioned above is a continuation of the number from the previous stage, so as to ensure the randomness of the start number of the third stage (because the unit number of the first stage end time is random, refer to the foregoing implementation. The process of competition), and enables the site performing the third phase to have a common and randomly generated starting time unit number, which can effectively guarantee the fairness of the third phase. Certainly, the embodiment of the present invention can also support the first and third stages to be independently numbered. In this case, the fairness of the third stage is difficult to guarantee, or a complicated manner is needed to achieve fairness. Or it can be used when there is a low demand for fairness.

Optionally, the foregoing successful passing means that when the station performs competition in the competition retreat window of the first stage, the station randomly generates a first retreat time point number (equivalent to a time unit in the first competitive retreat window). Number), then the station listens to the unlicensed carrier before the arrival of the first retreat point number (the station counts down from the randomly obtained time unit number, when the countdown is 0), when listening to the unlicensed carrier If it is empty (the energy in the carrier is below the threshold), then the station successfully passes the first stage. When the unlicensed carrier is busy (the energy in the carrier is higher than the threshold), the station suspends the competition and waits for the next time. . The third stage of implementing competition is similar.

The duration of the third stage of the competitive retreat window can be designed as needed. For example, it can be set to a fixed duration, so that the total number of time units in the competition fallback window is equal to the maximum number of sites participating in each competition (the maximum number depends on the specific deployment of the network, which can be counted), and can be Assign a unique number. In this way, the point of retreat in the third stage of the second contention fallback window is unique, and no conflict occurs (ie, multiple stations simultaneously compete for the use rights of the unlicensed carrier). For another example, the duration of the second competitive retreat window of the third stage may be designed according to actual conditions. In order to save time resources, consider the number of stations that successfully reach the third stage through the first stage, that is, each time the third stage is executed. The number of stations can be counted, and the number of time units included in the third-stage competitive fallback window is designed according to the average value, for example, the average value is set to the number of time units included in the third-stage competitive fallback window. In this way, setting the third-stage competitive fallback window duration is the most effective, and the conflicts in the third-stage competitive fallback window can be completely avoided or greatly reduced.

Optionally, the starting number of the time unit of the competition back window of the third stage is the number of the time unit of the first stage or the second stage, and the time number of the end of the first stage is randomly generated by the station, and is Random numbers generated by multiple sites and the same number (or the same fallback time point), so the starting number of the time unit of the third-stage competitive fallback window is still random, and is randomly generated by multiple sites. And the same number.

The above is a further detailed description of the present invention in connection with the specific embodiments, and the specific embodiments of the present invention are not limited to the description.

One of ordinary skill in the art will appreciate that all or a portion of the steps of the above-described embodiments can be implemented using a computer program flow, which can be stored in a computer readable storage medium, such as on a corresponding hardware platform (eg, The system, device, device, device, etc. are executed, and when executed, include one or a combination of the steps of the method embodiments.

Alternatively, all or part of the steps of the above embodiments may also be implemented by using an integrated circuit. These steps may be separately fabricated into individual integrated circuit modules, or multiple modules or steps may be fabricated into a single integrated circuit module. achieve.

The devices/function modules/functional units in the above embodiments may be implemented by a general-purpose computing device, which may be centralized on a single computing device or distributed over a network of multiple computing devices.

When each device/function module/functional unit in the above embodiment is implemented in the form of a software function module and sold or used as a stand-alone product, it can be stored in a computer readable storage medium. The above mentioned computer readable storage medium may be a read only memory, a magnetic disk or an optical disk or the like.

Industrial applicability

The above technical solution avoids conflicts caused by multiple transmission nodes competing for unauthorized carrier usage rights at the same time, causing channel interference, resulting in data transmission failure, thereby making the competition of the unlicensed carrier usage rights fair and reasonable, and the unlicensed carrier is reasonably utilized.

Claims

A method for achieving unlicensed carrier usage rights competition, comprising:

Each of the transmitting nodes randomly generates a first back-off time point number of each of the first competitive back-off windows;

Each of the transmitting nodes simultaneously listens to the unlicensed carrier in the respective first contention retreat window. Before the first retreat time point number arrives, if the unlicensed carrier is always heard to be idle, the second contention retreat is continued. Unlicensed carrier usage rights competition within the window; if the unlicensed carrier is detected to be busy, the unlicensed carrier usage right competition is stopped;

The transmission node that competes for the unlicensed carrier usage right in the second contention fallback window performs data transmission on the unlicensed carrier.
The method of claim 1 further comprising:

Before the non-authorized carrier usage right competition is performed in the second contention retreat window, the first retreat time point number arrives before the non-authorized carrier is always idle, and the number arrives at the first retreat time point. And transmitting, by using the unlicensed carrier, a first signal, where the first signal is used to indicate that the unlicensed carrier is busy.
The method according to claim 1, wherein the transmission node comprises: a base station site, or a cell under a base station site, or a user terminal UE;

The unlicensed carrier usage right competition in the second contention fallback window includes:

The first backoff time point number of the transmitting node that continues the unlicensed carrier usage right competition in the second contention retreat window plus one or the first backoff time point number plus the first signal transmission duration plus one is used as the a starting number of the back-off unit of the second contention fallback window, and a number of the transmitting node that performs the unlicensed carrier usage right competition in each of the second contention retreat windows as its corresponding second back-off time point Numbering;

Starting from the second back-off time point number, starting from the countdown to the start number of the back-off unit of the second competitive back-off window, and counting the countdown to the start number of the back-off unit of the second competitive fallback window, The unlicensed carrier obtains the unlicensed carrier usage right for the idle transmitting node;

Wherein, when the transmitting node is a base station site, the number of the transmitting node is preset;

When the transmitting node is a cell under the base station site, the number of the transmitting node is a physical ID of the cell;

When the transmitting node is a UE, the number of the transmitting node includes: after the UE belongs to the UE, the physical ID of the virtual cell is the number of the UE, or the station to which the UE belongs is allocated to the UE. The cell radio network temporary identifier C-RNTI is the number of the UE.
The method of claim 3, wherein

The starting number of the back-counting unit from the second back-off time point number to the second competitive back-off window includes:

When the second backoff time point number of the transit node that continues the unlicensed carrier usage right competition in the second contention fallback window is smaller than the start number of the backoff unit of the second contention fallback window, After the second back-off time point number starts counting down to 0, the number of the total number of transmitting nodes that compete for the unlicensed carrier usage rights is started, and the countdown to the back-off unit of the second competitive back-off window is continued. Start number.
The method of claim 1, wherein the unlicensed carrier usage rights competition in the second contention fallback window comprises:

Obtaining the number of neighboring transmission nodes actually deployed by the transmission node or the total number of back-off units in the second contention retreat window,

And when the first backoff time point number of the transmitting node that continues to compete for the unlicensed carrier usage right in the second contention retreat window is greater than the total number of back-off units in the second contention retreat window, a back-off time point number plus a pair of second competitive back-off windows, a total number of rollback units, a starting number of the back-off unit as the second competitive back-off window; or, a second competitive fallback window If the first backoff time point number of the transit node that continues to compete for the unlicensed carrier usage right is less than the total number of backoff units in the second competitive backoff window, the first backoff time point number is incremented by one. a starting number of a fallback unit as the second contention fallback window;

And the neighboring transmission node number of the transmitting node that continues the unlicensed carrier usage right competition in the second contention retreat window is used as the corresponding second backoff time point number, and the countdown to the second contention retreat window is performed. The starting number of the rollback unit, when the countdown counts to the start number of the backoff unit of the second contention fallback window, and the unlicensed carrier obtains the unauthorized carrier use right for the idle transit node;

or,

The first backoff time point number of the transmitting node that continues the unlicensed carrier usage right competition in the second contention retreat window plus the time length of sending the first signal plus one is greater than the total backoff in the second contention retreat window The number of units is taken as the starting number of the first back-off time point number plus a total number of back-off units in the second competition back-off window, and the starting number of the back-off unit as the second contention retreat window; or The first back-off time point number of the transmitting node that continues the unlicensed carrier usage right competition in the second contention retreat window plus the time length of transmitting the first signal plus one less than the total number of back-off units in the second contention retreat window, Taking the first back-off time point number plus the duration of transmitting the first signal plus one, the starting number of the back-off unit as the second contention retreat window;

Forwarding the adjacent transmission node number of each transmission node that continues the unlicensed carrier usage right competition in the second contention fallback window as its corresponding second backoff time point number, and performing a countdown to the second contention retreat window The starting number of the unit is rolled back. When the countdown counts to the starting number of the back-off unit of the second contention retreat window, the unlicensed carrier acquires the unauthorized carrier usage right for the idle transmitting node.
The method of claim 1, wherein the unlicensed carrier usage rights competition in the second contention fallback window comprises:

Obtaining the number of neighboring transmission nodes actually deployed by the transmission node or the total number of back-off units in the second contention retreat window,

Taking 0 as the starting number of the retreating unit of the second contention retreat window;

Forwarding the adjacent transmission node number of each transmission node that continues the unlicensed carrier usage right competition in the second contention fallback window as its corresponding second backoff time point number, and performing a countdown to the second contention retreat window The starting number of the unit is rolled back. When the countdown counts to the starting number of the back-off unit of the second contention fallback window, the unlicensed carrier acquires the unauthorized carrier usage right for the idle transmitting node.
The method according to claim 5 or 6, wherein

The starting number of the back-counting unit from the second back-off time point number to the second competitive back-off window includes:

When the second backoff time point number of the transit node that continues the unlicensed carrier usage right competition in the second contention retreat window is smaller than the start number of the backoff unit of the second contention fallback window, The second retreat time point number starts to count down to 0, and the total retraction window in the second competition retreat window The bit number value begins, and the countdown to the start number of the backoff unit of the second contention rewind window is continued.
The method according to any one of claims 2 to 6, wherein the first signal comprises: an occupation signal of an unlicensed carrier, and/or an agreed sequence signal, and/or a reference signal, and/or a synchronization signal;

The first signal transmission duration includes: a back-off unit of one or more contention retreat windows.
A transmission node that implements competition for unlicensed carrier usage rights, comprising: a random number unit, a first contention unit, a second contention unit, and a transmission unit;

a random number unit, configured to randomly generate its first backoff time point number in the first contention fallback window;

The first contention unit is configured to simultaneously listen to the unlicensed carrier in the first contention retreat window, and before the arrival of the first retreat time point number, if the unlicensed carrier is always heard to be idle, continue the second competition. Unauthorized carrier usage right competition within the window; if the unlicensed carrier is detected to be busy, the unlicensed carrier usage right competition is stopped;

a second contention unit, configured to compete for unauthorized carrier usage rights in the second contention fallback window;

The transmitting unit is configured to perform data transmission on the unlicensed carrier when competing for obtaining the unlicensed carrier usage right in the second contention retreat window.
The transmission node according to claim 9, further comprising a notification unit configured to always listen before the arrival of the first retreat time point number before the non-authorized carrier usage right competition is performed in the second contention fallback window When the unlicensed carrier is idle, the first signal is sent by using the unlicensed carrier when the first rewinding point number arrives, so that other transmitting nodes can detect that the unlicensed carrier is busy;

The first signal includes an occupancy signal of an unlicensed carrier, and/or an agreed sequence signal, and/or a reference signal, and/or a synchronization signal.
The transmission node according to claim 9, wherein the transmission node comprises: a base station station, or a cell under a base station station, or a user terminal UE;

The second contention unit is set to,

When the non-authorized carrier usage right competition is continued in the second contention fallback window, the first fallback time is The point number plus one or the first back-off time point number plus the first signal transmission time plus one, as the starting number of the back-off unit of the second contention retreat window, with its own number as its corresponding second back-off Time point number;

Starting from the second back-off point number, starting from the countdown to the start number of the back-off unit of the second competitive back-off window, when the countdown is counted to the start number of the back-off unit of the second contention fallback window, the unlicensed carrier is Get free access to unauthorized carriers when you are free;

When the transmitting node is a base station site, the number of the transmitting node is a preset number;

When the transmitting node is a cell under the base station site, the number of the transmitting node is a physical ID of the cell;

When the transmitting node is a UE, the number of the transmitting node includes: after the UE belongs to the UE, the physical ID of the virtual cell is the number of the UE, or the station to which the UE belongs is allocated to the UE. The cell radio network temporary identifier C-RNTI is the number of the UE.
The transmission node according to claim 11, wherein the second contention unit is further configured to

When the second back-off time point number is smaller than the start number of the back-off unit of the second contention retreat window,

Starting from the second backoff time point number and counting down to 0, starting with the total number of the transmitting nodes that compete for the unlicensed carrier usage rights, continuing the countdown to the start of the backoff unit of the second competitive backoff window Numbering;

When the countdown is counted to the start number of the backoff unit of the second contention fallback window, and the unlicensed carrier is idle, the unlicensed carrier usage right is acquired and data transmission is performed.
The transmission node according to claim 9, wherein said second contention unit is set to

Obtaining the number of neighboring transport nodes actually deployed by the transport node or the total number of back-off units in the second competing backoff window,

When the first backoff time point number plus one is greater than the total number of back-off units in the second competitive back-off window, the first back-off time point number is added, and the total number of back-off units in the second competitive back-off window is taken. The starting number of the retreating unit as the second competitive retreat window; or, if the first retreat time point number plus one is less than the total number of retreating units in the second competitive retreat window, the first retreat time is taken Point number plus one The starting number of the fallback unit as the second competitive fallback window;

The neighboring transmission node number of the transmission node itself in the second contention retreat window is used as its corresponding second backoff time point number, and the starting number of the back-off unit of the second competition back-off window is counted down, when the countdown is counted to The starting number of the back-off unit of the second contention retreat window, and the unlicensed carrier is used for the unlicensed carrier;

or,

The first back-off time point number plus the number of the first signal sent by the transmission node plus the number of adjacent transmission nodes of the actually deployed transmission node, and the first back-off time point number plus a pair of second competition back-off windows The number of units to be retired, the starting number of the unit of the retreat as the second competitive retreat window; or, the number of the first retreat point plus the length of the first signal sent plus one less than the total retreat in the second competitive retreat window For the number of units, the first retraction time point number plus the first signal transmission time plus one, the starting number of the retreat unit as the second competition retreat window;

Taking the adjacent transmission node number of the transmission node as its corresponding second backoff time point number, performing a countdown to the start number of the backoff unit of the second contention retreat window, when the countdown is counted to the second contention retreat window The starting number of the fallback unit and the unlicensed carrier are idle, and the unlicensed carrier usage right is obtained.
The transmission node according to claim 9, wherein said second contention unit is set to

Obtaining the number of neighboring transport nodes actually deployed by the transport node or the total number of back-off units in the second competing backoff window,

0 is the starting number of the fallback unit of the second competitive fallback window;

Taking the neighboring transmission node number of the transmission node as its corresponding second backoff time point number, performing a countdown to the start number of the backoff unit of the second contention retreat window, when the countdown counts back to the second contention retreat window The starting number of the retiring unit. When the unlicensed carrier is idle, the unlicensed carrier usage right is obtained.
The transmission node according to claim 13 or 14, wherein the second contention unit is further configured to

When the second backoff time point number of the transit node is smaller than the start number of the backoff unit of the second contention fallback window,

After the countdown to 0 is started from the second backoff time point number, starting with the total number of back-off unit numbers in the second contention retreat window, and continuing the countdown to the start number of the back-off unit of the second competition retreat window;

When the countdown is counted to the start number of the backoff unit of the second contention fallback window, and the unlicensed carrier is idle, the unlicensed carrier use right is acquired.
A competitive fallback method includes:

The transmission node divides the time direction into a first phase, a second phase, and a third phase;

The first phase and the third phase are composed of several time units, and the time units of the first phase, the second phase and the third phase are numbered;

The transmitting node performs interception in the first phase; the first signal is sent in the second phase by the transmitting node in the first phase, and the interception is continued in the third phase; and the contention rollback is completed through the transport node in the third phase;

The first phase, the second phase, and the third phase are continuous in time, each phase lasting for a certain length of time.
The contention fallback method of claim 16, wherein the first phase is a first contention fallback window and the third phase is a second contention fallback window.
A method of competing for fallback according to claim 16 or 17, wherein

The starting number of the time unit number of the third stage includes: adding the first backing time point number of the transmitting node of the first stage plus one or the first backing time point number of the first stage plus sending the first signal Add one more time; or,

When the first backoff time point number of the transmission node in the third stage is greater than the total value of the time unit included in the third stage, the start number of the time unit number of the third stage includes: taking the first The retraction time point number plus a pair of the total number of time units included in the third stage is taken; or

When the first backoff time point number of the transmission node in the third stage is greater than the total value of the time unit included in the third stage, the start number of the time unit number of the third stage includes: Retract the time point number plus one; or,

When the first back-off time point number of the transmission node in the third stage is greater than the total value of the time unit included in the third stage, the first back-off time point number is added with a pair of times included in the third stage. The value of the number of units is taken as the starting number of the time unit number of the third stage; or,

When the first backoff time point number of the transmission node in the third stage is greater than or equal to the total value of the time unit included in the third stage, the first backoff time point number is incremented by one as the time unit of the third stage. The starting number of the number; or,

The start number of the time unit number of the third stage is 0.
The method for competing for fallback according to claim 18, wherein when the start number of the time unit number of the third stage is the first back-off time point number plus one or the first back-off time point number plus the transmission When the first signal duration is further increased, the second backoff time point number of the third stage is the number of the transmission node that performs the unlicensed carrier usage right competition in the third stage; the third stage loop number is the time unit included in the third stage. Total value;

When the start number of the time unit number of the third stage is taken, and the number of the first time period and the total number of time units included in the third stage are taken, the third stage continues to be unauthorized. The adjacent transmission node number of the transmission node that the carrier usage right competes as its corresponding second backoff time point number; the loop number of the third stage is the total value of the time unit included in the third stage;

When the first backoff time point number of the transmission node in the third stage is greater than the total value of the time unit included in the third stage, and the first backoff time point number is incremented by one, the unlicensed carrier is continued in the third stage. The neighboring transmission node number of each transmission node that uses the right to compete as its corresponding second backoff time point number; the loop number of the third stage is the total number of time units included in the third stage;

When 0 is used as the starting number of the time unit number of the third stage, the neighboring transmission node number of each transmitting node that continues the unlicensed carrier usage right competition in the third stage is taken as its corresponding second backoff time point number. ;

When the first retracted time point number plus a pair of values of the total number of time units included in the third stage is used as the starting number of the time unit number of the third stage, the second retreat time point of the third stage is used. The number of the transmission node numbered as the third phase for the unlicensed carrier usage right competition; the third phase of the cycle number is the total number of time units included in the third phase;

The first retracting time point number of the transmission node in the third stage is increased by one or less than or equal to the third The total number of time units included in the phase, when the first backoff time point number is added plus one as the starting number of the time unit number of the third phase, and the third phase of the third phase is the third phase. The number of the transmitting node that is authorized to use the carrier usage right; the number of the third phase is the total number of time units contained in the third phase.
The method of competitive fallback according to claim 19, further comprising:

When the second back-off time point number of the third stage is smaller than the start number of the time unit number of the third stage, the countdown from the second back-off time point number to 0, from the third stage Starting with the cycle number, continuing the countdown to the start number of the time unit number of the third phase;

When the second backoff time point number of the third stage is greater than or equal to the start number of the time unit number of the third stage, the transmission node directly counts down.
The method of competing for fallback according to claim 16 or 17, wherein said first phase, second phase, and third phase are consecutively included in time: a time unit number of said first phase and a third phase The time unit number is continuous.
The method of competing for fallback according to claim 16 or 17, wherein when there are also a plurality of time units in the second phase, the first phase, the second phase, and the third phase are consecutively included in time: first The time unit number of the phase is continuous with the time unit number of the second phase, and the time unit number of the third phase is continuous with the time number of the second phase.
The method of competing for fallback according to claim 16 or 17, wherein said numbering the time units of the first phase and the third phase comprises: independently numbering the time units of the first phase, and time for the third phase Units are numbered independently.
The method of competing for fallback according to claim 16 or 17, wherein when the transmitting node performs a contention fallback in the first phase and the third phase, the passing includes: when the first fallback time of the transmission phase Before the point number arrives or the transmission node counts down from the first back-off time point number down counter to 0, the transmission phase intercepts the unauthorized carrier usage right is always idle.
The method for competing for fallback according to claim 20, wherein the contention fallback method is applied to the use right competition of the unlicensed carrier, and the unlicensed carrier use right is obtained through the transport node of the third stage;

The transmission node passing through the third stage is the start of the time unit number of the third stage No., listens to the transit node where the unlicensed carrier is always idle.
A computer storage medium having stored therein computer executable instructions for performing the method of any one of claims 1-8.
A computer storage medium having stored therein computer executable instructions for performing the method of any one of claims 16-25.