CN107295567A - A kind of unlimited resources collision detection method based on frame structure - Google Patents

Abstract

The invention relates to a frame structure-based infinite resource conflict detection method, which belongs to the field of wireless communication. The method includes the following steps: S1: divide the wireless frame into a collision detection area and a data transmission area; S2: divide the collision detection code carried by the collision detection time slot into a high-priority collision detection code and a low-priority collision detection code; The code is sent on the collision detection time slot; S3: The device detects all the collision detection codes in the collision detection time slot, evaluates the severity of the collision in the data transmission area by detecting the number of collision detection codes, and determines the backoff time of the device ; If no other device is found to send a collision detection code, the device uses the wireless resources in the data transmission area. The invention solves the problem of using the transmission resource competition under the condition of frame synchronization; in addition, the collision detection code is divided into different priorities, and is suitable for the scene where different priorities compete to use the transmission resources.

Description

A Frame-Based Infinite Resource Conflict Detection Method

technical field

The invention belongs to the field of wireless communication, and relates to a frame structure-based infinite resource conflict detection method.

Background technique

Using the distributed control method, each node attached to the bus obtains the right to use the bus through competition. Only nodes that have obtained usage rights can send information frames to the bus, which will be sensed by all nodes attached to the bus. Including the following three main points: first: carrier sense, the sending node must listen to whether the medium is idle before sending the information frame; second: multiple access, has two meanings, it means that multiple nodes can Accessing the media at the same time also means that the information frame sent by a node can be received by multiple nodes; third: conflict detection, the sending node must monitor the media while sending the information frame to determine whether a conflict occurs (at the same time, Whether other nodes are also sending information frames). There are currently two methods available, Carrier Sense Multiple Access/Collision Detection Mechanism (abbreviation: CSMA/CD, Carrier Sense Multiple Access/Collision Detect) and Carrier Sense Multiple Access/Collision Avoidance (abbreviation: CSMA/CA) .

CSMA/CD mode, that is, carrier sense multiple access/collision detection mechanism. When multiple network devices on the wired Ethernet need to transmit data at the same time, this protocol can detect the conflicts on the network and deal with them accordingly. Its working principle can be summed up as listening first and then speaking, and speaking while listening; once there is a conflict, stop talking immediately; wait for the opportunity, and then speak. But it is not suitable for wireless local area network. In wireless local area network, the transmission distance of radio waves is limited, and not all nodes can listen to the signal; moreover, because the wireless network card works in half-duplex mode, the device cannot receive data signals. while transmitting data signals. On the other hand, the wireless bandwidth is inherently low, and once a collision occurs, the data will be resent, and the throughput will be reduced accordingly.

CSMA/CD has made some modifications and adopted a new protocol CSMA/CA. The working principle of CSMA/CA is as follows:

(1) Firstly, it is detected whether the channel is used by a station (referred to as: STA). If the channel is detected to be idle, the data is sent after waiting for the distributed coordination function inter-frame space (referred to as: DIFS).

(2) If the destination STA receives the frame correctly, it will send an acknowledgment frame ACK to the source STA after a short interframe space (abbreviation: SIFS) time.

(3) The source STA receives the ACK frame and confirms that the data transmission is correct. After the DIFS time interval, there will be a period of idle time, which is called the contention window, indicating that the STAs will compete for the channel.

If the channel is found to be occupied during channel detection, the STA will use the backoff algorithm of the CSMA/CA protocol to freeze the backoff timer. The backoff timer counts down as long as the channel is free. When the backoff timer decreases to zero, the STA sends a data frame and waits for an acknowledgment. If no ACK frame is received after sending a data frame, the frame must be retransmitted.

There is a problem in the current CSMA/CD or CSMA/CA. When multiple stations request to send data, conflicts will occur. Because the severity of the conflict is not known, all stations can only back off according to the same mechanism, and participate again. A round of clash competition. This method has obvious defects in the actual deployment of applications:

First: When multiple sites request to send data at the same time, conflicts will occur, but each site only knows that other sites are also requesting to send data, but does not know how many sites are requesting to send, so the severity of the conflict cannot be determined to evaluate.

Second: When conflicts occur in the data sent by the site, the degree of conflict cannot be evaluated objectively, so there is no way to give a reasonable backoff time, and only a random backoff time can be selected within a certain period of time.

Third: There are different priorities for sending data from stations, but according to the current implementation, there is no way to increase the probability of sending data with high priority. That is to say, in practical applications, for example, signaling can be set as a high priority, and has the priority to send in conflicts and competitions.

Therefore, the current CSMA/CD or CSMA/CA has certain defects in actual use.

Contents of the invention

In view of this, the purpose of the present invention is to provide a method for competing to use wireless resources in a wireless communication system. The principle is to use wireless frames to manage and use wireless resources. First, the wireless frames are divided into a conflict detection area and a data transmission area. , a collision detection area and a data transmission area constitute a transmission unit. The collision detection area is used to coordinate multiple devices to compete for the use of the data transmission area, and is composed of multiple collision detection time slots. The data transmission area is used for the device to transmit high-priority or low-priority data, and the data transmission area can be composed of multiple data transmission frames.

To achieve the above object, the present invention provides the following technical solutions:

A frame structure-based infinite resource conflict detection method, the method includes the following steps:

S1: Divide the wireless frame into a conflict detection area and a data transmission area. A conflict detection area and a data transmission area form a transmission unit; a conflict detection area consists of multiple conflict detection time slots, which are used to coordinate multiple devices to compete for data transmission Area, the data transmission area is composed of multiple data transmission frames, used for equipment to transmit high-priority or low-priority data;

S2: Divide the collision detection code carried by the collision detection slot into a high-priority collision detection code and a low-priority collision detection code; if the device sends high-priority data, randomly select one of the high-priority For low-priority data, one of the low-priority collision detection codes is randomly selected; the collision detection code is sent on the collision detection time slot;

S3: The device detects all the collision detection codes in the collision detection time slot, evaluates the severity of the collision in the data transmission area by detecting the number of collision detection codes, and determines the backoff time of the device; if no other device is found to send a collision detection code, the device uses the wireless resources in the data transmission area.

Further, in the step S3:

If the device does not find the conflict detection code sent by other devices, it is determined that the device has the right to use the data transmission area;

If the device finds the conflict detection codes sent by other devices, and all the conflict detection codes have a lower priority than the conflict detection codes of this device, the device has the right to use the data transmission area;

If the device finds that the priority of the collision detection code sent by other devices is the same as or higher than that of the device, the device will choose a reasonable backoff time and participate in the competition of the transmission unit, that is, the wireless resource again.

Further, in the step S3:

The device detects t high-priority collision detection codes, where t≥0, and s low-priority collision detection codes, where s≥0; when the device detects t+s≠0; if the device sends high-priority data, Then the device randomly selects a transmission unit in the subsequent transmission units 0~t to compete for wireless resources; if the device sends low-priority data, the device randomly selects a transmission unit in the subsequent transmission units t~t+s to participate in wireless resources competition;

Further description, in the conflict scenario, the device chooses to use subsequent transmission unit numbers starting from 0, and the transmission unit whose backoff is 0 is the conflicting transmission unit;

The device waits for the randomly selected transmission unit time to arrive. When the transmission unit time arrives, the device reselects the collision detection code and participates in the process of competing for the use of the data transmission area again.

The beneficial effects of the present invention are:

(1) The present invention solves the problem of contention and use of transmission resources under the condition of frame synchronization. Under the existing frame synchronization method, the transmission resources are allocated and used in a unified manner, and there is no competing use scenario. However, with the increase of business and scenarios, although different devices have the same frame synchronization, there are also scenarios of competing use of transmission resources. .

(2) The present invention uses an orthogonal collision detection code to obtain the severity of the collision when a device detects a collision, and determines the number of devices competing to use the same transmission resource.

(3) The present invention divides the collision detection codes into different priorities, and can adapt to the scenario where different priorities compete to use transmission resources.

Description of drawings

In order to make the purpose, technical scheme and beneficial effect of the present invention clearer, the present invention provides the following drawings for illustration:

FIG. 1 is a schematic diagram of wireless resource collision detection based on a frame structure;

Fig. 2 is a wireless resource coordination process diagram based on a frame structure;

Fig. 3 is the back-off mechanism in wireless transmission conflict;

FIG. 4 is a conflict resolution mechanism in the conventional CP mode;

Figure 5 shows the conflict resolution mechanism in the extended CP mode;

Fig. 6 is the conflict resolution mechanism in LTE frame mode;

Fig. 7 is the collision avoidance mechanism in LTE frame mode;

FIG. 8 is a schematic diagram of a scenario where a small cell and a mobile terminal compete to use multiple transmission units;

FIG. 9 is a multi-channel collision avoidance mechanism in LTE frame mode.

detailed description

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in Figure 1, the present invention manages and uses wireless resources in a wireless frame manner. First, the wireless frame is divided into a collision detection area and a data transmission area, and a collision detection area and a data transmission area constitute a transmission unit. The collision detection area is used to coordinate multiple devices to compete for the use of the data transmission area, and is composed of multiple collision detection time slots. The data transmission area is used for the device to transmit high-priority or low-priority data, and the data transmission area can be composed of multiple data transmission frames.

The collision detection time slot in each collision detection area may carry multiple collision detection codes with orthogonal properties. The collision detection codes are divided into two groups, high priority collision detection codes and low priority collision detection codes. If the device sends a high priority If it is low-priority data, randomly select one of the low-priority collision detection codes, and send the collision detection code on the collision detection time slot.

When the device performs collision detection, it first detects all the collision detection codes in the collision detection time slot, and evaluates the severity of the collision in the data transmission area by detecting the number of collision detection codes, and then determines the backoff time of the device. If no other device is found to send the collision detection code, the device can use the wireless resources in the data transmission area.

The frame structure-based wireless resource coordination process provided by the present invention will be specifically described below, as shown in FIG. 2 .

Step 1: The codewords of all collision detection codes used by the devices are orthogonal, and all devices use the same method to divide the collision detection codes into two groups, namely, high priority and low priority collision detection codes. Step 1 in Figure 2.

Step 2: If the device requests to send high-priority data, then randomly select a code from the high-priority collision detection codes, if it is low-priority data, then randomly select a code from the low-priority collision detection codes, and It is sent on the subsequent collision detection time slot. Steps 2, 3, 4, and 5 in Figure 2.

Step 3: After the device randomly selects a collision detection time slot in the subsequent collision detection time slots, the device stops sending the collision detection code on the collision detection time slot, and detects the collision code sent by other devices on the collision detection time slot. detection code. Step 6 in Figure 2.

Step 4: If in step 3, the device does not find the conflict detection code sent by other devices, then it is determined that the device has the right to use the data transmission area. Steps 7 and 8 in Figure 2.

Step 5: If in step 3, the device finds the conflict detection codes sent by other devices, and all the conflict detection code priorities are lower than the priority of the conflict detection code of the device, then the device has the right to use the data transmission area .

Step 6: If in step 3, the device finds that the priority of the collision detection code of other devices is the same as or higher than that of the device, the device will choose a reasonable backoff time and participate in the transmission unit, that is, the competition for wireless resources again. Steps 9, 10, and 11 in Figure 2.

The following specifically describes the backoff process of the wireless resource conflict coordination based on the frame structure provided by the present invention, as shown in FIG. 3 .

Step 1: The device randomly selects a collision detection time slot in the upcoming collision detection area, that is, randomly selects a collision detection time slot in collision detection areas 1-M as shown in FIG. 1 . Step 1 in Figure 3.

Step 2: The device will detect all collision detection codes in the randomly selected collision detection time slot. Suppose the device detects t high-priority collision detection codes (t is greater than or equal to 0), and s low-priority collision detection codes. (s is greater than or equal to 0). If the device does not find the high-priority collision detection code and the low-priority collision detection code, the device has the right to use wireless resources in the data transmission area. Steps 2, 3, 4, and 5 in Figure 3.

Step 3: If in the second step, the device detects that t+s is not equal to 0, and if the device sends high-priority data, the device randomly selects a transmission unit from the subsequent transmission units 0~t to compete for the use of wireless resources, where If the randomly selected subsequent transmission unit is 0, it means that this conflicting transmission unit is selected for data transmission. If the device sends low-priority data, the device randomly selects a transmission unit in the subsequent transmission units t~t+s to participate in the competition for wireless resources. Steps 6, 7, and 8 in Figure 3.

Step 4: The device waits for the arrival of the randomly selected transmission unit time. When the transmission unit time arrives, the device reselects the collision detection code and participates in the process of competing for the use of the data transmission area again. Step 9 in Figure 3.

Two application scenarios are described below as examples. The first is a scenario where LTE small cells compete to use radio resources, and the second is a scenario where LTE mobile terminals perform direct communication.

Specific embodiment 1:

In the deployment and application of LTE small cells in the future, plug-and-play is a development direction, which can be deployed similarly to WiFi hotspots, but the plug-and-play function of small cells will have a great impact on the planning and use of wireless resources. The main reason is that there is no way for different small cells to coordinate the use of radio resources in a timely manner, so it is inevitable that small cells compete to use radio resources. The present invention provides a method to resolve this conflict.

In order to clearly illustrate the usage details of the present invention, the following will describe from two perspectives, firstly, a method in which multiple LTE terminals compete to use the same transmission unit, and then a method in which multiple LTE terminals compete to use multiple transmission units.

Before data transmission between multiple small cells and LTE terminals, they need to compete to use the same transmission unit. Before describing the specific operation method, the basic concepts are introduced first:

First: time slot resource division: continue to use the current LTE frame structure, if it is a normal CP mode, then a subframe is divided into 14 orthogonal frequency division multiplexing (referred to as: OFDM) symbols, of which the first 7 OFDM symbols are used In the collision detection area, each symbol is defined as a collision detection time slot, as shown in FIG. 4 . If it is the extended CP mode, a subframe has 12 OFDM symbols, and the first 3 OFDM symbols are defined as the collision detection area, as shown in Figure 5. In actual use, the number of collision detection time slots (that is, the number of OFDM in this embodiment) may vary according to different systems. For the convenience of description, in this implementation example, the normal CP mode will be used, that is, there are 7 collision detection time slots (7 OFDM time slots) to illustrate the specific implementation of the invention.

Second: the definition of the transmission unit: according to the requirements of the present invention, the transmission unit is composed of a conflict detection area and a data transmission area. In this embodiment, it is assumed that the data transmission area is composed of a sending data area 1 and a sending data area 2. The data area may be one or more subframe radio resources. For the convenience of description, the sending data area 2 is composed of two subframes with a length of 1 ms.

Third: Transmission data priority: The data sent in the data transmission area is divided into two types, signaling data and business data. The signaling data is defined as high-priority data in the present invention, and service data is defined as low-priority data in the present invention.

Fourth: Collision detection codes: In this implementation example, ZC sequences are used as the collision detection codes, and different ZC sequence codes in the ZC sequences are orthogonal to each other.

The following specifically introduces the data transmission between the small cell and the mobile terminal, mainly introducing the operation process of coordinating conflicts and using transmission resources. Specifically shown in Figure 6.

Step 1: After the small cell base station is powered on, it first searches for nearby macro base stations. If no macro base station is received, it continues to search for nearby small cell base stations. The purpose of this process is to ensure that all small cells in an area are kept in sync. , that is, have frequency and frame timing synchronization. Step 1 in Figure 6.

Step 2: When the small cell base station sends downlink data to the mobile terminal, or when the small cell receives a request from the mobile terminal to send uplink data, that is, data transmission between the small cell and the mobile terminal needs to occupy wireless resources. Steps 2 and 3 in Figure 6.

Step 3: The small cell base station first determines the type of data to be sent. If it is signaling data, it is defined as high-priority data, and if it is service data, it is defined as low-priority data. If it is high-priority data, a high-priority orthogonal collision detection code is randomly selected, and if it is low-priority data, a low-priority orthogonal collision detection code is randomly selected. Steps 4, 5, and 6 in Figure 6.

Step 4: The small cell will wait for the arrival of the next transmission unit time. The specific calculation method is SFN% T_Schedule = T_Offset, where SFN means that all small cells maintain the same system frame number (unit is radio frame), and T_Schedule represents the length of the transmission unit , which means how many wireless frames. T_Offset represents the offset. T_Schedule and T_Offset are preset, and all small cells use the same parameters. In this example, T_Schedule=3 and T_Offset=0. Step 7 in Figure 6.

Step 5: When a transmission unit arrives, the small cell will send an orthogonal collision detection code on the collision detection time slot of the transmission unit. Slots need to be sent. Step 8 in Figure 6.

Step 6: The small cell randomly selects a collision detection time slot from all the collision detection time slots of the transmission unit. Detect whether there are other small cells that need to send data. If there is an orthogonal collision detection code, it means that other small cells are also requesting to use the transmission unit; otherwise, it means that no other small cells are requesting to use the transmission unit. Step 9 in Figure 6.

Step 7: If the small cell detects the orthogonal collision detection code in the collision detection time slot, the small cell will start the collision avoidance mechanism in the present invention, otherwise it means that the transmission unit can be used for data transmission between the small cell and the mobile terminal . 10 steps as shown in Figure 6.

The following specifically introduces the backoff mechanism when the LTE terminal requests to use transmission resource conflicts. Specifically shown in Figure 7.

Step 1: The small cell randomly selects a collision detection time slot, and stops sending the small cell's orthogonal collision detection code in this collision detection time slot. Step 1 in Figure 7.

Step 2: The small cell receives data on the selected collision detection time slot, and detects all orthogonal collision detection codes. Assume that there are t high-priority orthogonal collision detection codes and s low-priority orthogonal collision detection codes are detected. Step 2 in Figure 7.

Step 3: t+s orthogonal collision detection codes are detected, and if t+s=0, it indicates that no other small cell competes to use the transmission unit, and this small cell can use the data transmission area resources on the transmission unit. Steps 3 and 4 in Figure 7.

Step 4: If t+s is not equal to 0, it means that other small cells are also competing to use the data transmission area resources of the transmission unit. If signaling data is sent between the small cell and the mobile terminal, the small cell will be in [ 1, t] (indicates that between 1 and t, including 1 and t) transmission units, a transmission unit is randomly selected, and the transmission unit participates in the contention of transmission resources in the case of collision again. If the service data is sent between the small cell and the mobile terminal, the small cell is in [(t+1),(t+s)] (indicating between t+1 and t+s, including t+1 and t Randomly select a transmission unit from the +s) transmission units, and participate in the contention of transmission resources in the case of collision again on this transmission unit.

Steps 5, 6, and 7 in Figure 7.

Step 5: After randomly selecting a transmission unit, the small cell reselects the corresponding orthogonal collision detection code, waits for the arrival of the selected transmission unit, and then participates in the collision detection of the transmission unit again to complete the process of competing for transmission resources. Steps 8 and 9 in Figure 7.

The above shows a scenario where multiple small cells and terminals compete to use one transmission unit. In practical applications, small cells and mobile terminals may compete to use transmission units provided by different frequency points. The following specifically introduces the method of using the present invention to solve the competition between multiple small cells and mobile terminals for using multiple transmission units.

A scenario where multiple small cells and mobile terminals compete to use multiple transmission units is specifically shown in FIG. 8 . It is assumed that K transmission units can be used between the small cell and the mobile terminal. Each channel is independent of each other, and the transmission unit of each channel also starts from the position of SFN%T_Schedule=T_Offset, and each transmission unit has its own conflict detection area and data sending area.

The following specifically introduces the processing flow when multiple small cells and LTE terminals use multiple sets of transmission resources to request data transmission and conflict. Specifically as shown in Figure 9.

Step 1: The small cell first determines available transmission resources in the area, that is, determines available transmission channels, assuming that there are K independent transmission channels. Step 1 in Figure 9.

Step 2: The small cell that needs to send or receive data randomly selects a channel from channel numbers 1 to k, assuming that the randomly selected channel number is z, where z is an integer between 1 and k (may include 1 and k). Step 2 in Figure 9. The small cells first compete to use the transmission unit on channel k.

Step 3: The small cell competes to use the transmission unit resource on the channel k according to the manner in which multiple small cells and the mobile terminal conflict to use the transmission resource. Step 3 in Figure 9.

Specific embodiment 2:

In order to better illustrate that the present invention can be used in practice, the proof will be continued below. In an environment without any base station coverage, LTE terminals need to communicate with each other, especially in emergency or disaster relief scenarios, since LTE base stations cannot be used, it is very necessary to support communication between LTE terminals. Because in the same area, there may be many pairs of LTE terminals that need to communicate with each other, but there is no way to coordinate the use of radio resources among them, and a conflict and competition method needs to be adopted. This scenario is a device-to-device (abbreviation: D2D) scenario, so the present invention can also be applied in the process of competing to use D2D transmission resources.

In the LTE system D2D, there are two ways to use radio resources, one is to determine the radio resources of the D2D terminal by the base station scheduling, that is, the time-frequency resource used by the base station scheduling D2D terminal transmission. In another way, the network configures a set of radio resources or the terminal defaults a set of radio resources, and then the D2D terminal randomly selects a set of radio resources to use. In the second case, since there is no base station to coordinate radio resources among D2D terminals, there is a situation that D2D terminals compete to use radio resources. In the D2D terminal direct connection scenario, the patent of the present invention can well solve the conflict caused by wireless resources when there is no base station scheduling.

Combining with the description in the above specific embodiment 1, the specific method for solving the D2D terminal direct communication is as follows.

Step 1: Power on the D2D terminal, first search for the base station signal, if no base station signal is found, then search for the synchronization signal sent by the nearby D2D terminal to ensure that the D2D terminal in communication refers to the same LTE wireless frame time slot and the same system frame No.

Step 2: According to the definition of the current 3GPP standard, the wireless resources used by the D2D terminal direct connection come from system message broadcast, connection mode configuration and terminal default configuration. Among them, system message broadcast and connection mode configuration must be that the terminal is within the signal coverage of the base station, and the network can configure wireless resources so that the requesting D2D terminal can randomly select and use it. If the D2D is in an area without base station coverage, the D2D terminal can only randomly select a default radio resource to use.

Step 3: If the D2D terminal needs to send signaling data, the D2D terminal randomly selects one of the high-priority orthogonal collision detection codes; if the D2D terminal sends service data, the D2D terminal randomly selects one of the low-priority orthogonal collision detection codes. choose one.

Step 4: The D2D terminal randomly selects a group of wireless resource groups for use. And according to SFN%T_Schedule=T_Offset, the transmission unit for collision detection is determined.

Step 5: The D2D terminal sends the selected orthogonal collision detection code on the collision detection time slot in the collision detection area of the transmission unit, and when a randomly selected collision detection time slot arrives, D2D stops sending its own collision detection code , while detecting whether other D2D terminals have sent collision detection codes.

Step 6: If the D2D terminal detects the collision detection code sent by other D2D terminals on the collision detection time slot, the D2D terminal starts the backoff mechanism in the patent of the present invention for processing.

Step 7: If the D2D terminal does not detect the collision detection code sent by other D2D terminals in the collision detection time slot, then the D2D terminal has the right to send data on the transmission unit.

Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that it can be described in terms of form and Various changes may be made in the details without departing from the scope of the invention defined by the claims.

Claims (3)

1. a kind of unlimited resources collision detection method based on frame structure, it is characterised in that：This method comprises the following steps：

S1：Radio frames are divided into collision detection area and data transmission range, a collision detection area and a data transmission range are constituted One transmission unit；Collision detection area is made up of multiple collision detection time slots, is passed for coordinating multiple equipment competition using data Defeated area, data transfer area is made up of multiple data transmission frames, and the data of high priority or low priority are transmitted for equipment；

S2：The collision detection code division that collision detection time slot is carried into high priority collision detection code and low priority collision detection Code；One is randomly choosed from high priority collision detection code if equipment sends high-priority data, if equipment is sent Lower-priority data then randomly chooses one from low priority collision detection code；By collision detection code on collision detection time slot Send；

S3：Equipment detects collision detection codes all in collision detection time slot, by detecting that the quantity of collision detection code is assessed The conflict order of severity that data transfer area is present, and with the back off time of this determination equipment；If not finding that other equipment is sent out Collision detection code is sent, then equipment uses the Radio Resource in data transfer area.

2. a kind of unlimited resources collision detection method based on frame structure as claimed in claim 1, it is characterised in that：Described In step S3：

If equipment does not find the collision detection code that other equipment is sent, it is determined that this equipment possesses the right to use in data transfer area Limit；

If equipment is found that the collision detection code that other equipment is sent, and all collision detection code priority is below this Equipment collision detection code priority, then the equipment possess the right to use in data transfer area；

If equipment finds that the priority for the collision detection code that other equipment is sent is identical with this equipment or higher than this equipment, The equipment will select a rational back off time, and the competition that transmission unit is Radio Resource is participated in again.

3. a kind of unlimited resources collision detection method based on frame structure as claimed in claim 1, it is characterised in that：Described In step S3：

Equipment, which detects high priority collision detection code, has t individual, wherein t >=0, low priority collision detection code s, and wherein s >= 0；When equipment detects t+s ≠ 0；If equipment send high-priority data, equipment in follow-up 0~t of transmission unit with Machine selects a transmission unit competition to use Radio Resource；If equipment sends lower-priority data, equipment is in follow-up biography The competition that a transmission unit participates in Radio Resource is randomly choosed in defeated unit t~t+s；

Further describe, in conflict scene, equipment selection is numbered since 0 using follow-up transmission unit, keeps out of the way the biography for 0 Defeated unit is this transmission unit of conflict；

Equipment waits the transmission unit time randomly choosed out to arrive, and when the transmission unit time reaches, equipment reselects conflict Detection code, participates in process of the competition using data transfer area again.