CN108566683B

CN108566683B - Method and device for accessing unauthorized frequency band, electronic equipment and readable storage medium

Info

Publication number: CN108566683B
Application number: CN201810752718.4A
Authority: CN
Inventors: 张奇勋; 冯志勇; 侯佳; 尉志青; 黄赛
Original assignee: Beijing University of Posts and Telecommunications
Current assignee: Beijing University of Posts and Telecommunications
Priority date: 2018-07-10
Filing date: 2018-07-10
Publication date: 2020-01-10
Anticipated expiration: 2038-07-10
Also published as: CN108566683A

Abstract

The embodiment of the invention provides a method, a device, electronic equipment and a readable storage medium for accessing an unauthorized frequency band, wherein the method comprises the following steps: acquiring a CQI value at the current moment; searching a current modulation mode, a current coding rate and current efficiency corresponding to the CQI value at the current moment, coding data to be transmitted in the current modulation mode, and calculating the physical layer rate of the LTE system; calculating the access probability when the total throughput is the maximum value according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network equipment in the wireless network system and other related parameters; calculating a current back-off time window according to the transmission probability, the packet loss probability, the access probability and the CQI value at the current moment; and randomly selecting a positive integer as a current backoff counter in the current backoff time window, accessing an unauthorized frequency band according to the current backoff counter and the access probability, and transmitting the coded data to be transmitted to the user terminal through the unauthorized frequency band.

Description

Method and device for accessing unauthorized frequency band, electronic equipment and readable storage medium

Technical Field

The present invention relates to the field of wireless communications technologies, and in particular, to a method and an apparatus for accessing an unlicensed frequency band, an electronic device, and a readable storage medium.

Background

With the development of wireless communication technology, the requirements of wireless users on the speed and the network quality of a wireless network are higher and higher, however, the licensed spectrum resources used by the wireless network are limited, which makes the contradiction between the increasing wireless network requirements and the limited licensed spectrum resources increasingly prominent.

In 2015, a 3GPP (3rd Generation partnership project) standard organization provides an LAA (licensed Assisted Access) technology, and the LAA technology aggregates an unlicensed frequency band and an licensed frequency band through a carrier aggregation technology, so that an LTE (long term Evolution) system cooperatively works on the licensed frequency band and the unlicensed frequency band, which can improve the resource utilization rate of an idle unlicensed frequency band and relieve the pressure of high traffic demand in the licensed frequency band.

When an existing LTE system accesses an unlicensed frequency band, a simple Listen-before-talk (Listen-before-talk, LBT) mechanism is mainly used, that is, carrier sensing is performed before the existing LTE system accesses the unlicensed frequency band, and data transmission is performed after a carrier is idle for a certain time. However, because the physical address layer protocol of the wireless network system is based on carrier sense multiple access with collision avoidance, when contending for unauthorized frequency band resources with the LTE system, if channel collision occurs, the wireless network system will frequently back off, and the LTE system will occupy most of spectrum resources of the unauthorized frequency band, which causes a large decrease in throughput of the wireless network, and reduces coexistence performance of the LTE system and the wireless network system.

Disclosure of Invention

Embodiments of the present invention provide a method, an apparatus, an electronic device, and a readable storage medium for accessing an unlicensed frequency band, so as to calculate a reasonable current backoff time window for an LTE system, so as to improve coexistence performance of the LTE system and a wireless network system. The specific technical scheme is as follows:

in a first aspect, an embodiment of the present invention provides a method for accessing an unlicensed frequency band, where the method includes:

when a data packet to be sent exists in an LTE system, acquiring a Channel Quality Indicator (CQI) value at the current moment reported by a user terminal which establishes connection with the LTE system;

searching a current modulation mode, a current coding rate and current efficiency corresponding to a CQI value at the current moment through a preset CQI value table, and coding data to be sent in the current modulation mode to obtain currently coded data to be sent, wherein the preset CQI value table comprises the CQI value, a modulation mode corresponding to the CQI value, a coding rate corresponding to the CQI value and efficiency corresponding to the CQI value;

calculating the physical layer rate of the LTE system according to the current modulation mode, the current coding rate and the current efficiency;

acquiring a prestored physical layer rate of the wireless network system, and calculating access probability when the total throughput of the LTE system and the wireless network system is the maximum value according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network equipment in the wireless network system and other related parameters; wherein, other relevant parameters include: the method comprises the following steps of determining the length of a data packet of a wireless network system, the length of a data packet of an LTE system, the length of time for the wireless network system to successfully transmit data, the length of time for the LTE system to successfully transmit data, the length of data collision, the length of a time slot and the access probability of the wireless network system, wherein the wireless network system is a system using an unauthorized frequency band;

acquiring a pre-stored transmission probability of data packet transmission on a channel and a packet loss probability caused by collision, and calculating a current back-off time window of the LTE system corresponding to a CQI value at the current moment according to the transmission probability, the packet loss probability, the access probability and the CQI value at the current moment;

and in the current backoff time window, randomly selecting a positive integer as a current backoff counter, accessing an unauthorized frequency band according to the current backoff counter and the access probability, and transmitting the encoded data to be transmitted to the user terminal through the unauthorized frequency band.

In a second aspect, an embodiment of the present invention provides an apparatus for accessing an unlicensed frequency band, where the apparatus includes:

the device comprises an acquisition module, a sending module and a sending module, wherein the acquisition module is used for acquiring a Channel Quality Indicator (CQI) value at the current moment reported by a user terminal which establishes connection with an LTE system when the LTE system has a data packet to be sent;

the encoding module is used for searching a current modulation mode, a current encoding rate and current efficiency corresponding to the CQI value at the current moment through a preset CQI value table, and encoding data to be transmitted in the current modulation mode to obtain currently encoded data to be transmitted, wherein the preset CQI value table comprises the CQI value, the modulation mode corresponding to the CQI value, the encoding rate corresponding to the CQI value and the efficiency corresponding to the CQI value;

the physical layer rate calculation module is used for calculating the physical layer rate of the LTE system according to the current modulation mode, the current coding rate and the current efficiency;

the access probability calculation module is used for acquiring the physical layer rate of the wireless network system which is stored in advance, and calculating the access probability when the total throughput of the LTE system and the wireless network system is the maximum value according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of the wireless network devices in the wireless network system and other related parameters; wherein, other relevant parameters include: the method comprises the following steps of determining the length of a data packet of a wireless network system, the length of a data packet of an LTE system, the length of time for the wireless network system to successfully transmit data, the length of time for the LTE system to successfully transmit data, the length of data collision, the length of a time slot and the access probability of the wireless network system, wherein the wireless network system is a system using an unauthorized frequency band;

the back-off time window calculation module is used for acquiring the pre-stored transmission probability of data packet transmission on a channel and the packet loss probability caused by collision, and calculating the current back-off time window of the LTE system corresponding to the CQI value at the current moment according to the transmission probability, the packet loss probability, the access probability and the CQI value at the current moment;

and the access module is used for randomly selecting a positive integer as a current backoff counter in a current backoff time window, accessing the unauthorized frequency band according to the current backoff counter and the access probability, and transmitting the coded data to be transmitted to the user terminal through the unauthorized frequency band.

In a third aspect, an embodiment of the present invention further provides an electronic device, which is characterized by including a processor, a communication interface, a memory, and a communication bus, where the processor, the communication interface, and the memory complete mutual communication through the communication bus;

a memory for storing a computer program;

and the processor is used for realizing the steps of any one of the methods for accessing the unauthorized frequency band when executing the program stored in the memory.

In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, where a computer program is stored in the computer-readable storage medium, and when the computer program is executed by a processor, the computer program implements any of the steps of the method for accessing an unlicensed frequency band.

When a data packet to be sent exists in an LTE system, a CQI value at a current time reported by a user terminal that establishes a connection with the LTE system may be first obtained, and a current modulation method, a current coding rate, and a current efficiency corresponding to the CQI value at the current time are searched through a preset CQI value table, so that data to be sent is coded in the current modulation method, and a physical layer rate of the LTE system may be calculated according to the current modulation method, the current coding rate, and the current efficiency; then, the prestored physical layer rate of the wireless network system, the prestored transmission probability and packet loss probability can be obtained, and the access probability when the total throughput of the LTE system and the wireless network system is the maximum value is calculated according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network equipment in the wireless network system and other related parameters; and calculating a current backoff time window of the LTE system corresponding to the CQI value at the current moment according to the transmission probability, the packet loss probability, the access probability and the CQI value at the current moment, finally, randomly selecting a positive integer as a current backoff counter in the current backoff time window, accessing an unauthorized frequency band according to the current backoff counter and the access probability, and transmitting the coded data to be transmitted to the user terminal through the unauthorized frequency band. Therefore, when the LTE system is accessed to the unauthorized frequency band, the total throughput of the LTE system and the wireless network system can be ensured to be maximum by adopting the access probability and the backoff time window, so that the reasonable current backoff time window can be calculated for the LTE system, and the coexistence performance of the LTE system and the wireless network system can be improved. Of course, not all of the above advantages need be achieved in the practice of any one product or method of the present invention.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flowchart of a first implementation manner of a method for accessing an unlicensed frequency band according to an embodiment of the present invention;

fig. 2 is a diagram of a markov chain model of a method for accessing an unlicensed frequency band according to an embodiment of the present invention;

fig. 3 is a flowchart of a second implementation manner of a method for accessing an unlicensed frequency band according to an embodiment of the present invention;

fig. 4 is a flowchart of a third implementation manner of a method for accessing an unlicensed frequency band according to an embodiment of the present invention;

fig. 5 is a flowchart of a fourth implementation manner of a method for accessing an unlicensed frequency band according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of an apparatus for accessing an unlicensed frequency band according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to solve the problems in the prior art, embodiments of the present invention provide a method, an apparatus, an electronic device, and a readable storage medium for accessing an unlicensed frequency band, so as to calculate a reasonable current backoff time window for an LTE system, so as to improve coexistence performance of the LTE system and a wireless network system.

In the following, a method for accessing an unlicensed frequency band according to an embodiment of the present invention is first described, where the method may be applied to any LTE base station in an LTE system, as shown in fig. 1, which is a flowchart of a first implementation manner of the method for accessing an unlicensed frequency band according to the embodiment of the present invention, and in fig. 1, the method may include:

s110, when a data packet to be sent exists in the LTE system, a channel quality indicator CQI value at the current moment reported by a user terminal which establishes connection with the LTE system is obtained.

Specifically, when the LTE system has a data packet to be sent, in order to enable the LTE system to access the unlicensed frequency band with a more reasonable access probability, the LTE system may first obtain a CQI value at a current time from a user terminal that establishes a connection with the LTE system.

In some examples, the user terminal may actively report the CQI value at the current time to the LTE system, or may send the CQI value at the current time to the LTE system after the LTE system sends the CQI value acquisition request.

And S120, searching a current modulation mode, a current coding rate and a current efficiency corresponding to the CQI value at the current moment through a preset CQI value table, and coding the data to be transmitted by current modulation to obtain the currently coded data to be transmitted.

The preset CQI value table includes a CQI value, a modulation scheme corresponding to the CQI value, a coding rate corresponding to the CQI value, and an efficiency corresponding to the CQI value.

In some examples, the preset CQI value table may be a first preset CQI value table shown in table 1;

TABLE 1 first Preset CQI value Table

CQI value	Modulation system	Encoding rate	Efficiency of	CQI value	Modulation system	Encoding rate	Efficiency of
								0	Out of range	/	/	8	16QAM	0.48	1.9141
1	QPSK	0.076	0.1523	9	16QAM	0.6	2.4063
								2	QPSK	0.12	0.2344	10	64QAM	0.45	2.7305
3	QPSK	0.19	0.3770	11	64QAM	0.55	3.3223
								4	QPSK	0.3	0.6016	12	64QAM	0.65	3.9023
5	QPSK	0.44	0.8770	13	64QAM	0.75	4.5234
								6	QPSK	0.59	1.1758	14	64QAM	0.85	5.1152
7	16QAM	0.37	1.4766	15	64QAM	0.93	5.5547

If the CQI value obtained by the LTE system is 7, the modulation 16QAM corresponding to the CQI value of 7 can be found in the preset CQI value table, the coding rate is 0.37, and the efficiency is 1.47.

And S130, calculating the physical layer rate of the LTE system according to the current modulation mode, the current coding rate and the current efficiency.

After the current modulation mode, the current coding rate and the current efficiency are found through the preset CQI value table, the LTE system may calculate the physical layer rate of the LTE system according to the current modulation mode, the current coding rate and the current efficiency.

In some examples, the physical layer rate of the LTE system may be calculated using prior art calculations. And will not be described in detail herein.

S140, the prestored physical layer rate of the wireless network system is obtained, and the access probability when the total throughput of the LTE system and the wireless network system is the maximum value is calculated according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of the wireless network devices in the wireless network system and other related parameters.

Among other relevant parameters, the other relevant parameters may include: the wireless network system is a system using an unauthorized frequency band.

Specifically, after the LTE system calculates the own physical layer rate, the physical layer rate of the wireless network system stored in advance may be obtained locally.

In some examples, the physical layer rate of the wireless network system may be pre-calculated and stored into the LTE system.

In some examples, when the LTE system obtains the physical layer rate of the LTE system and the physical layer rate of the wireless network system, the limitation condition of the access probability may be first calculated.

Specifically, the LTE system may be based on the physical layer rate of the LTE system

Physical layer rate for wireless network systems

Number N of wireless network devices in wireless network system, and packet length E of wireless network system_w[P]Packet length E of LTE system_l[P]Time length T of successful data transmission of wireless network system_swTime length T of successful data transmission of LTE system_slAccess probability tau of wireless network system_wThe time length Tc of the data collision and the length δ of one slot are calculated by the following formula:

first constraint F for calculating access probability₁And a second limiting condition F₂Wherein, in the step (A),

when the LTE system calculates the limit of the access probabilityAfter conditioning, the first limiting condition F can be obtained by calculation₁As the lowest limiting condition, with a second limiting condition F₂Is the highest limiting condition.

That is, F₁≤τ_l≤F₂Then, the access probability when the total throughput of the LTE system and the wireless network system is the maximum value can be calculated according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network devices in the wireless network system, and other related parameters.

In some examples, the LTE system described above is under a first constraint F₁As the lowest limiting condition, with a second limiting condition F₂When calculating the access probability that the total throughput of the LTE system and the wireless network system is the maximum value according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network devices in the wireless network system, and other related parameters, the maximum limit condition may be calculated in the following manner:

specifically, the LTE system may use the first constraint F₁As the lowest limiting condition, with a second limiting condition F₂According to the physical layer rate of LTE system as the highest limiting condition

Physical layer rate for wireless network systemsNumber N of wireless network devices in wireless network system, and normalized throughput of wireless network systemNormalized throughput for LTE systems

Packet length E for wireless network systems_w[P]Packet length E of LTE system_l[P]Time length T of successful data transmission of wireless network system_swTime length T of successful data transmission of LTE system_slAccess probability tau of wireless network system_wTime length of data collision T_cAnd the length of the slot, δ, by the following equation:

calculating an access probability tau at which a total throughput of the LTE system and the wireless network system is maximized_lWherein, in the step (A),

by the step, the access probability when the total throughput of the LTE system and the wireless network system is the maximum value can be calculated, so that the total throughput is the maximum value when the access probability is used for accessing the unauthorized frequency band, and the coexistence performance of the LTE system and the wireless network system can be improved.

S150, obtaining the pre-stored transmission probability of data packet transmission on the channel and the packet loss probability caused by collision, and calculating the current back-off time window of the LTE system corresponding to the CQI value at the current time according to the transmission probability, the packet loss probability, the access probability and the CQI value at the current time.

Specifically, after the LTE system calculates the access probability, in order to enable the LTE system to fairly access the unlicensed frequency band, the LTE system may first obtain, from a channel stored in advance locally, a transmission probability that a data packet is transmitted and a packet loss probability caused by a collision.

In some examples, the transmission probability and the packet loss probability may be pre-tested and stored in the LTE system.

In some examples, after obtaining the transmission probability and the packet loss probability, the LTE system may calculate a current backoff time window of the LTE system corresponding to the CQI value at the current time according to the transmission probability, the packet loss probability, the access probability, and the CQI value at the current time.

Specifically, when the LTE system calculates the current backoff time window, the LTE system may calculate the current backoff time window according to the transmission probability q, the packet loss probability p, and the access probability τ_lAnd a CQI value at the current time by the following formula:

W_CQI＝(16-CQI)·w

calculating a current back-off time window W of the LTE system corresponding to the CQI value at the current time_CQIWhere w is the unitized back-off time window.

In some examples, in order to obtain a formula for calculating a back-off time window, a markov chain model may be pre-constructed in an embodiment of the present invention, as shown in fig. 2, which is a markov chain model diagram constructed in a method for accessing an unlicensed frequency band in an embodiment of the present invention, and in fig. 2, because modulation modes adopted when CQI values are 1 to 6 are all QPSK modulation modes; when the CQI values are 7 to 9, the modulation schemes used are all 16QAM modulation schemes, and when the CQI values are 10 to 15, the modulation schemes used are all 64QAM modulation schemes, a markov chain model including three modulation schemes can be constructed, and it is assumed that in the model, the QPSK modulation scheme is used as an L layer, the 16QAM modulation scheme is used as an M layer, and the 64QAM modulation scheme is used as an H layer, and each layer can select any one of the CQI values in the layers different from the current layer with the same probability. Then, the steady state transition probability of the markov chain model can be obtained according to the transmission probability q, the packet loss probability p, and all CQI values:

wherein q is the transmission probability of data packets on the channel, p is the packet loss probability caused by collision, and pi_IIs the steady state probability, pi, of the channel idle state_s,j,0For all layers with a CQI value of j and a contention window of 0, the steady-state probability, pi_H,j,iRepresents the steady-state probability, pi, of the H-layer CQI value being j and the contention window size being i_H,j,i+1Is the steady state probability, W, of the H-layer CQI value being j and the contention window being i +1_HIs the size of the contention window for the H layer,when the CQI of the H layer is j, the contention window is W_HSteady state probability of state at-1, π_M,j,iThe steady state probability, pi, of the M layers with CQI value j and contention window i_M,j,i+1Is the steady state probability, pi, of the M-layer CQI value being j and the contention window being i +1_H,j,0Is the steady-state probability when the H-layer CQI value is j and the contention window is 0,

for M layers CQI value of j, contention window is W_MSteady state probability at 1, W_MIs the size of the contention window of the M layers, pi_L,j,iFor a steady state probability, π, of L-layer CQI value j and contention window i_L,j,i+1Is the steady state probability, W, of the L-layer CQI value being j and the contention window being i +1_LIs the size of the M-layer contention window, pi_M,j,0Is the steady-state probability, pi, of the M-layer CQI value being j and the contention window being 0_L,j,0Is the steady-state probability when the L-layer CQI value is j and the contention window is 0,

for L-layer CQI value of j, contention window is W_LSteady state probability at-1, π_s,j,iSteady state probability with a contention window of i for all layers with CQI value j.

By solving the above-mentioned steady state transition probability, the following formula can be obtained:

that is, a relational expression between the access probability and the unitized backoff time window may be obtained, and the unitized backoff time window may be calculated from the relational expression.

Through the step, the calculated backoff time window can be calculated according to the access probability, so that the LTE system can back off in a more reasonable mode when back off is carried out according to the backoff time window, long-term occupation of an unauthorized frequency band is avoided, and coexistence performance of the LTE system and a wireless network system is improved.

And S160, randomly selecting a positive integer as a current backoff counter in the current backoff time window, accessing the unauthorized frequency band according to the current backoff counter and the access probability, and transmitting the coded data to be transmitted to the user terminal through the unauthorized frequency band.

After the current backoff time window is obtained by calculation, the LTE system may randomly select a positive integer as a current backoff counter in the current backoff time window, and perform counting, and when the current backoff counter is counted as 0, the LTE system may access an unauthorized frequency band according to the access probability, and transmit the encoded data to be transmitted to the user terminal through the unauthorized frequency band.

Specifically, if the LTE system detects that the idle length of the unlicensed frequency band reaches one timeslot, the backoff counter is decremented by 1, and so on until the count of the backoff counter is 0.

In some examples, if the LTE system detects that the unlicensed frequency band is busy, the backoff counter suspends counting until the unlicensed frequency band becomes idle again, and continues counting until the backoff counter counts to 0.

By the method for accessing the unauthorized frequency band, when a data packet to be sent exists in the LTE system, a CQI value at the current moment reported by a user terminal which is connected with the LTE system can be firstly obtained, a current modulation mode, a current coding rate and current efficiency which correspond to the CQI value at the current moment are searched through a preset CQI value table, then data to be sent are coded through current modulation, and the physical layer rate of the LTE system can be calculated according to the current modulation mode, the current coding rate and the current efficiency; then, the prestored physical layer rate of the wireless network system, the prestored transmission probability and packet loss probability can be obtained, and the access probability when the total throughput of the LTE system and the wireless network system is the maximum value is calculated according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network equipment in the wireless network system and other related parameters; and calculating a current backoff time window of the LTE system corresponding to the CQI value at the current moment according to the transmission probability, the packet loss probability, the access probability and the CQI value at the current moment, finally, randomly selecting a positive integer as a current backoff counter in the current backoff time window, accessing an unauthorized frequency band according to the current backoff counter and the access probability, and transmitting the coded data to be transmitted to the user terminal through the unauthorized frequency band. Therefore, when the LTE system is accessed to the unauthorized frequency band, the total throughput of the LTE system and the wireless network system can be ensured to be maximum by adopting the access probability and the backoff time window, so that the reasonable current backoff time window can be calculated for the LTE system, and the coexistence performance of the LTE system and the wireless network system can be improved.

In a possible implementation manner of the embodiment of the present invention, the LTE system may further determine the unlicensed frequency band, and execute corresponding steps according to a determination result. As shown in fig. 3, which is a flowchart of a second implementation manner of a method for accessing an unlicensed frequency band according to an embodiment of the present invention, in fig. 3, before acquiring a channel quality indicator CQI value at a current time reported by a user terminal that establishes a connection with an LTE system in S100, the method for accessing an unlicensed frequency band according to an embodiment of the present invention may further include:

s170, acquiring a preset CCA threshold value for evaluating a free channel, and evaluating whether an unauthorized frequency band is free or not according to the preset CCA threshold value; executing S100 when the unauthorized frequency band is busy, and acquiring a CQI value at the current moment reported by a user terminal which establishes connection with an LTE system; when the unlicensed frequency band is idle, executing step S180;

and S180, directly accessing the unauthorized frequency band.

In some examples, in the LTE system, the CCA threshold value may be stored in advance, and the CCA threshold value may be set in advance according to experience. Therefore, the LTE system may acquire the CCA threshold value.

After the preset CCA threshold is obtained, the LTE system may evaluate the unlicensed frequency band according to the preset CCA threshold to obtain a corresponding evaluation result.

It should be understood that the LTE system may adopt an evaluation manner in the prior art to evaluate the unlicensed frequency band, and details thereof are not described here.

By evaluating the unauthorized frequency band, the LTE system can directly access the unauthorized frequency band without calculating the access probability and the backoff time window when the unauthorized frequency band is idle, thereby reducing the time overhead of accessing the unauthorized frequency band.

For this reason, a possible implementation manner is also provided in the embodiment of the present invention, as shown in fig. 4, which is a flowchart of a third implementation manner of a method for accessing an unlicensed frequency band according to an embodiment of the present invention, where in fig. 4, after transmitting encoded data to be transmitted to a user terminal through the unlicensed frequency band, the method for accessing an unlicensed frequency band according to the embodiment of the present invention may further include:

and S190, after receiving the feedback message of data transmission failure sent by the user terminal, acquiring the block error rate carried in the feedback message, and comparing the block error rate with a preset block error rate threshold value.

In some examples, the preset block error rate threshold may be a threshold that is empirically preset, e.g., the preset block error rate threshold may be set to 10%.

In some examples, the user terminal may send a feedback message of data transmission failure to the LTE system when receiving data failure, and therefore, the LTE system may receive the feedback message sent by the user terminal, and of course, when the user terminal receives data successfully, the LTE system may send a feedback message of data transmission success to the LTE system.

After the LTE system receives the feedback message indicating that the data transmission fails, the block error rate carried in the feedback message may be obtained, and then the block error rate may be compared with a preset block error rate threshold.

And S200, when the block error rate is less than or equal to a preset block error rate threshold, increasing the current backoff time window or reducing a preset CCA threshold.

In some examples, when the block error rate is less than or equal to the preset block error rate threshold, it may be stated that the cause of the data transmission failure is a collision between multiple systems in the access process, and for this reason, the LTE system may enable the LTE system to have a larger time window by increasing the current backoff time window, or enable the LTE system to more easily detect whether the unlicensed frequency band is idle by reducing the preset CCA threshold.

In some examples, 1 may be added to the current backoff time window, or 1 may be subtracted from a preset CCA threshold value, etc. The value of the increase of the back-off time window and the value of the decrease of the preset threshold are not limited herein.

And S210, when the block error rate is greater than the preset block error rate threshold, coding the data packet to be transmitted by adopting a modulation mode with a lower order than the current modulation mode.

In some examples, when the block error rate is greater than the preset block error rate threshold, it may be shown that the cause of the data transmission failure is due to a condition deterioration of the unlicensed frequency band, and the LTE system may encode the data packet to be transmitted by using a modulation scheme lower than the current modulation scheme, so that the data can be successfully transmitted under the condition that the unlicensed frequency band is not good.

For example, assuming that the current modulation scheme is 64QAM, the LTE system may encode the data packet by using a 16QAM modulation scheme when the data packet is transmitted again. Thereby improving the probability of successful data transmission.

In a possible implementation manner of the embodiment of the present invention, a preset CQI value table further stores hierarchies, each hierarchy corresponding to at least one CQI value, for this, as shown in fig. 5, a method for accessing an unlicensed frequency band according to the embodiment of the present invention may further perform the following steps:

s121, searching a current modulation mode, a current coding rate and a current efficiency corresponding to the CQI value at the current moment and a current layer level corresponding to the CQI value at the current moment through a preset CQI value table.

In some examples, the preset CQI value table may be a second preset CQI value table shown in table 2,

in table 2, since the layer numbers L, M and H corresponding to the layers may be included, when the LTE system searches for the current modulation scheme, the current coding rate, and the current efficiency corresponding to the CQI value at the current time, the LTE system may also search for the current layer number corresponding to the CQI value at the current time.

For example, assuming that the current CQI value is 7, the LTE system may find that the current layer number corresponding to the current CQI value of 7 is M layers.

TABLE 2 second Preset CQI value Table

Correspondingly, in S160, in the back-off time window, a positive integer is randomly selected as the back-off counter, the current back-off counter and the access probability are accessed to the unauthorized frequency band, and after the encoded data to be transmitted are transmitted through the unauthorized frequency band, the method for accessing the unauthorized frequency band according to the embodiment of the present invention may further include:

and S220, when the LTE system collides with the wireless network system, reducing the level of the current layer to the level of the next layer, and coding the data packet to be transmitted in a modulation mode corresponding to the level of the next layer to obtain first coded data to be transmitted.

In some examples, after the coded data to be transmitted is transmitted through the unlicensed frequency band, the LTE system may collide with the wireless network system, and for the purpose of avoiding collision again after the collision and enabling the LTE system to more reasonably access the unlicensed frequency band, the LTE system may reduce the current level to a next level, and code the data packet to be transmitted in a modulation mode corresponding to the next level to obtain the first coded data to be transmitted.

For example, assuming that the current layer level is M layers, after the collision occurs, the LTE system may reduce the current layer level by one layer to L layers, and encode the data packet to be transmitted in a QPSK modulation scheme corresponding to the L layers.

And S230, selecting one CQI value from the plurality of CQI values corresponding to the next layer number as the CQI value of the next moment, and calculating the next back-off time window of the LTE system corresponding to the CQI value of the next moment according to the transmission probability, the packet loss probability, the access probability and the CQI value of the next moment.

In some examples, after a collision occurs, it is determined that the currently calculated backoff time window is unreasonable, and for this reason, the LTE system may select one CQI value from a plurality of CQI values corresponding to the next hierarchy as the CQI value at the next time, and then may calculate the next backoff time window of the LTE system corresponding to the CQI value at the next time according to the transmission probability, the packet loss probability, the access probability, and the CQI value at the next time. Thereby enabling recalculation of the back-off time window.

S240, in the next backoff time window, randomly selecting a positive integer as a next backoff counter, accessing the unauthorized frequency band according to the next backoff counter and the access probability, and transmitting the first coded data to be transmitted to the user terminal through the unauthorized frequency band.

Specifically, after the back-off time window is recalculated, in order to realize transmission of the first coded data to be transmitted, the LTE system may randomly select a positive integer as a next back-off counter in a next back-off time window, access the unauthorized frequency band according to the next back-off counter and the access probability, and transmit the first coded data to be transmitted to the user terminal through the unauthorized frequency band.

By the method for accessing the unauthorized frequency band, after collision occurs, the data to be transmitted can be coded and the back-off time window can be recalculated in a lower-level modulation mode, and back-off is performed according to the recalculated back-off time window, so that the unauthorized frequency band can be accessed after the back-off is finished, the transmission of the data to be transmitted after the re-coding is realized, and the successful probability of data transmission is improved.

Corresponding to the foregoing method embodiment, an embodiment of the present invention further provides a device for accessing an unlicensed frequency band, as shown in fig. 6, which is a schematic structural diagram of the device for accessing an unlicensed frequency band according to the embodiment of the present invention, and in fig. 6, the device may include:

an obtaining module 610, configured to obtain a channel quality indicator CQI value at a current time reported by a user terminal that establishes a connection with an LTE system when a to-be-sent data packet exists in the LTE system;

the encoding module 620 is configured to search, through a preset CQI value table, a current modulation mode, a current encoding rate, and a current efficiency that correspond to a CQI value at a current time, and encode data to be transmitted in the current modulation mode to obtain currently encoded data to be transmitted, where the preset CQI value table includes the CQI value, a modulation mode corresponding to the CQI value, an encoding rate corresponding to the CQI value, and an efficiency corresponding to the CQI value;

a physical layer rate calculating module 630, configured to calculate a physical layer rate of the LTE system according to the current modulation mode, the current coding rate, and the current efficiency;

the access probability calculation module 640 is configured to obtain a pre-stored physical layer rate of the wireless network system, and calculate an access probability when the total throughput of the LTE system and the wireless network system is a maximum value according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network devices in the wireless network system, and other related parameters; wherein, other relevant parameters include: the method comprises the following steps of determining the length of a data packet of a wireless network system, the length of a data packet of an LTE system, the length of time for the wireless network system to successfully transmit data, the length of time for the LTE system to successfully transmit data, the length of data collision, the length of a time slot and the access probability of the wireless network system, wherein the wireless network system is a system using an unauthorized frequency band;

a backoff time window calculation module 650, configured to obtain a pre-stored transmission probability that a data packet is transmitted on a channel and a packet loss probability caused by a collision, and calculate a current backoff time window of the LTE system corresponding to a CQI value at a current time according to the transmission probability, the packet loss probability, an access probability, and the CQI value at the current time;

the access module 660 is configured to randomly select a positive integer as a current backoff counter in the current backoff time window, access the unauthorized frequency band according to the current backoff counter and the access probability, and transmit the encoded data to be transmitted to the user terminal through the unauthorized frequency band.

By the device for accessing the unauthorized frequency band, provided by the embodiment of the invention, when a data packet to be sent exists in the LTE system, a CQI value at the current moment reported by a user terminal which is connected with the LTE system can be firstly obtained, a current modulation mode, a current coding rate and current efficiency which correspond to the CQI value at the current moment are searched through a preset CQI value table, then the data to be sent is coded in the current modulation mode, and the physical layer rate of the LTE system can be calculated according to the current modulation mode, the current coding rate and the current efficiency; then, the prestored physical layer rate of the wireless network system, the prestored transmission probability and packet loss probability can be obtained, and the access probability when the total throughput of the LTE system and the wireless network system is the maximum value is calculated according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network equipment in the wireless network system and other related parameters; and calculating a current backoff time window of the LTE system corresponding to the CQI value at the current moment according to the transmission probability, the packet loss probability, the access probability and the CQI value at the current moment, finally, randomly selecting a positive integer as a current backoff counter in the current backoff time window, accessing an unauthorized frequency band according to the current backoff counter and the access probability, and transmitting the coded data to be transmitted to the user terminal through the unauthorized frequency band. Therefore, when the LTE system is accessed to the unauthorized frequency band, the total throughput of the LTE system and the wireless network system can be ensured to be maximum by adopting the access probability and the backoff time window, so that the reasonable current backoff time window can be calculated for the LTE system, and the coexistence performance of the LTE system and the wireless network system can be improved.

Specifically, the apparatus for accessing an unlicensed frequency band according to the embodiment of the present invention may further include:

the unauthorized frequency band evaluation module is used for acquiring a preset clear channel evaluation CCA threshold value and evaluating whether the unauthorized frequency band is clear or not according to the preset CCA threshold value;

when the unauthorized frequency band is busy, triggering the acquisition module 610;

when the unlicensed frequency band is idle, the access module 660 is triggered to directly access the unlicensed frequency band.

the comparison module is used for acquiring the block error rate carried in the feedback message after receiving the feedback message of data transmission failure sent by the user terminal and comparing the block error rate with a preset block error rate threshold value;

the change module is used for increasing the current backoff time window or reducing the preset CCA threshold value when the block error rate is less than or equal to the preset block error rate threshold value; and when the block error rate is greater than a preset block error rate threshold value, coding the data packet to be transmitted by adopting a modulation mode with a lower order than the current modulation mode.

Specifically, the access probability calculating module 640 includes:

a constraint condition calculation submodule for calculating a constraint condition according to a physical layer rate of the LTE system

Physical layer rate for wireless network systems

Number N of wireless network devices in wireless network system, and packet length E of wireless network system_w[P]Packet length E of LTE system_l[P]Time length T of successful data transmission of wireless network system_swTime length T of successful data transmission of LTE system_slAccess probability tau of wireless network system_wTime length of data collision T_cAnd a length δ of one slot by the following formula:

an access probability calculation submodule for applying a first constraint F₁As the lowest limiting condition, with a second limiting condition F₂And calculating the access probability when the total throughput of the LTE system and the wireless network system is the maximum value according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of the wireless network devices in the wireless network system and other related parameters.

In particular, an access probability calculation submodule, in particular for

With a first limiting condition F₁As the lowest limiting condition, with a second limiting condition F₂According to the physical layer rate of LTE system as the highest limiting condition

Physical layer rate for wireless network systemsNumber N of wireless network devices in wireless network system, and normalized throughput of wireless network system

Normalized throughput for LTE systems

Packet length E for wireless network systems_w[P]Packet length E of LTE system_l[P]Time length T of successful data transmission of wireless network system_swTime length T of successful data transmission of LTE system_slAccess probability tau of wireless network system_wThe time length Tc of the data collision and the length δ of the time slot are represented by the following formulas:

specifically, the back-off time window calculating module 650 is specifically configured to:

according to the transmission probability q, the packet loss probability p and the access probability tau_lAnd a CQI value at the current time by the following formula:

W_CQI＝(16-CQI)·w

Specifically, the preset CQI value table further stores a hierarchy, each hierarchy corresponding to at least one CQI value, and the encoding module 620 is further configured to

And searching a current modulation mode, a current coding rate and a current efficiency corresponding to the CQI value at the current moment and a current layer level corresponding to the CQI value at the current moment through a preset CQI value table.

Specifically, the apparatus for accessing an unlicensed frequency band according to the embodiment of the present invention further includes:

the recoding module is used for reducing the level of the current layer to the level of the next layer when the LTE system collides with the wireless network system, and coding the data packet to be sent in a modulation mode corresponding to the level of the next layer to obtain first coded data to be sent;

a next backoff time window calculating module, configured to select one CQI value from multiple CQI values corresponding to the next layer number as a CQI value at the next time, and calculate a next backoff time window of the LTE system corresponding to the CQI value at the next time according to the transmission probability, the packet loss probability, the access probability, and the CQI value at the next time;

and the re-access module is used for randomly selecting a positive integer as a next backoff counter in a next backoff time window, accessing the unauthorized frequency band according to the next backoff counter and the access probability, and transmitting the first coded data to be transmitted to the user terminal through the unauthorized frequency band.

An embodiment of the present invention further provides an electronic device, as shown in fig. 7, including a processor 701, a communication interface 702, a memory 703 and a communication bus 704, where the processor 701, the communication interface 702, and the memory 703 complete mutual communication through the communication bus 704,

a memory 703 for storing a computer program;

the processor 701 is configured to implement the following steps when executing the program stored in the memory 703:

With the electronic device provided in the embodiment of the present invention, when a data packet to be sent exists in an LTE system, a CQI value at a current time reported by a user terminal that establishes a connection with the LTE system may be first obtained, and a current modulation mode, a current coding rate, and a current efficiency corresponding to the CQI value at the current time are searched through a preset CQI value table, so that data to be sent is coded in the current modulation mode, and a physical layer rate of the LTE system may also be calculated according to the current modulation mode, the current coding rate, and the current efficiency; then, the prestored physical layer rate of the wireless network system, the prestored transmission probability and packet loss probability can be obtained, and the access probability when the total throughput of the LTE system and the wireless network system is the maximum value is calculated according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network equipment in the wireless network system and other related parameters; and calculating a current backoff time window of the LTE system corresponding to the CQI value at the current moment according to the transmission probability, the packet loss probability, the access probability and the CQI value at the current moment, finally, randomly selecting a positive integer as a current backoff counter in the current backoff time window, accessing an unauthorized frequency band according to the current backoff counter and the access probability, and transmitting the coded data to be transmitted to the user terminal through the unauthorized frequency band. Therefore, when the LTE system is accessed to the unauthorized frequency band, the total throughput of the LTE system and the wireless network system can be ensured to be maximum by adopting the access probability and the backoff time window, so that the reasonable current backoff time window can be calculated for the LTE system, and the coexistence performance of the LTE system and the wireless network system can be improved.

The communication bus mentioned in the electronic device may be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. The communication bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is shown, but this does not mean that there is only one bus or one type of bus.

The communication interface is used for communication between the electronic equipment and other equipment.

The Memory may include a Random Access Memory (RAM) or a Non-Volatile Memory (NVM), such as at least one disk Memory. Optionally, the memory may also be at least one memory device located remotely from the processor.

The Processor may be a general-purpose Processor, including a Central Processing Unit (CPU), a Network Processor (NP), and the like; but may also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic device, discrete hardware component.

In a possible implementation manner of the embodiment of the present invention, an embodiment of the present invention further provides a computer-readable storage medium, in which a computer program is stored, and when executed by a processor, the computer program implements the following steps:

With the computer-readable storage medium provided in the embodiment of the present invention, when a data packet to be sent exists in an LTE system, a CQI value at a current time reported by a user terminal that establishes a connection with the LTE system may be first obtained, and a current modulation mode, a current coding rate, and a current efficiency corresponding to the CQI value at the current time are searched through a preset CQI value table, so that data to be sent is encoded in the current modulation mode, and a physical layer rate of the LTE system may also be calculated according to the current modulation mode, the current coding rate, and the current efficiency; then, the prestored physical layer rate of the wireless network system, the prestored transmission probability and packet loss probability can be obtained, and the access probability when the total throughput of the LTE system and the wireless network system is the maximum value is calculated according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network equipment in the wireless network system and other related parameters; and calculating a current backoff time window of the LTE system corresponding to the CQI value at the current moment according to the transmission probability, the packet loss probability, the access probability and the CQI value at the current moment, finally, randomly selecting a positive integer as a current backoff counter in the current backoff time window, accessing an unauthorized frequency band according to the current backoff counter and the access probability, and transmitting the coded data to be transmitted to the user terminal through the unauthorized frequency band. Therefore, when the LTE system is accessed to the unauthorized frequency band, the total throughput of the LTE system and the wireless network system can be ensured to be maximum by adopting the access probability and the backoff time window, so that the reasonable current backoff time window can be calculated for the LTE system, and the coexistence performance of the LTE system and the wireless network system can be improved.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

All the embodiments in the present specification are described in a related manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for accessing an unlicensed frequency band is applied to a Long Term Evolution (LTE) system, and comprises the following steps:

when a data packet to be sent exists in the LTE system, acquiring a Channel Quality Indicator (CQI) value at the current moment reported by a user terminal which establishes connection with the LTE system;

searching a current modulation mode, a current coding rate and current efficiency corresponding to the CQI value at the current moment through a preset CQI value table, and coding the data to be sent in the current modulation mode to obtain the currently coded data to be sent, wherein the preset CQI value table comprises the CQI value, the modulation mode corresponding to the CQI value, the coding rate corresponding to the CQI value and the efficiency corresponding to the CQI value;

acquiring a prestored physical layer rate of a wireless network system, and calculating access probability when the total throughput of the LTE system and the wireless network system is the maximum value according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network equipment in the wireless network system and other related parameters; wherein the other relevant parameters include: the method comprises the following steps of determining the length of a data packet of a wireless network system, the length of a data packet of an LTE system, the length of time for the wireless network system to successfully transmit data, the length of time for the LTE system to successfully transmit data, the length of data collision, the length of a time slot and the access probability of the wireless network system, wherein the wireless network system is a system using an unauthorized frequency band;

and randomly selecting a positive integer as a current backoff counter in the current backoff time window, accessing an unauthorized frequency band according to the current backoff counter and the access probability, and transmitting the coded data to be transmitted to the user terminal through the unauthorized frequency band.

2. The method of claim 1, wherein before the obtaining a Channel Quality Indicator (CQI) value at a current time reported by a user terminal that establishes a connection with the LTE system, the method further comprises:

acquiring a preset CCA threshold value for evaluating a free channel, and evaluating whether an unauthorized frequency band is free or not according to the preset CCA threshold value;

when the unauthorized frequency band is busy, executing the step of acquiring the CQI value at the current moment reported by the user terminal which establishes connection with the LTE system;

and when the unauthorized frequency band is idle, directly accessing the unauthorized frequency band.

3. The method according to claim 2, wherein after the transmitting the encoded data to be transmitted to the user terminal through the unlicensed frequency band, the method further comprises:

after receiving a feedback message of data transmission failure sent by the user terminal, acquiring a block error rate carried in the feedback message, and comparing the block error rate with a preset block error rate threshold;

when the block error rate is smaller than or equal to the preset block error rate threshold, increasing the current backoff time window or reducing the preset CCA threshold;

and when the block error rate is greater than the preset block error rate threshold value, coding the data packet to be sent by adopting a modulation mode with a lower order than the current modulation mode.

4. The method of claim 1, wherein the calculating the access probability according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network devices in the wireless network system, and other relevant parameters so that the total throughput of the LTE system and the wireless network system is the maximum value comprises:

according to the physical layer rate of the LTE system

Physical layer rate of the wireless network system

The number N of wireless network devices in the wireless network system and the length E of a data packet of the wireless network system_w[P]And the data packet length E of the LTE system_l[P]The time length T of successful data transmission of the wireless network system_swThe time length T of successful data transmission of the LTE system_slAccess probability tau of the wireless network system_wTime length of data collision T_cAnd a length δ of one slot by the following formula:

calculating the access probabilityFirst limitation condition F₁And a second limiting condition F₂Wherein, the

With the first limiting condition F₁Is the lowest limiting condition, and is the second limiting condition F₂And calculating the access probability when the total throughput of the LTE system and the wireless network system is the maximum value according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of the wireless network devices in the wireless network system and other related parameters.

5. Method according to claim 4, characterized in that said first limiting condition F₁Is the lowest limiting condition, and is the second limiting condition F₂Calculating the access probability when the total throughput of the LTE system and the wireless network system is the maximum value according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network devices in the wireless network system and other related parameters, which is the highest limiting condition, and comprises the following steps:

with the first limiting condition F₁Is the lowest limiting condition, and is the second limiting condition F₂According to the physical layer rate of the LTE system as the highest limiting condition

Physical layer rate of the wireless network system

The number N of wireless network devices in the wireless network system and the normalized throughput of the wireless network system

Of the LTE systemNormalized throughput

Packet length E of the wireless network system_w[P]And the data packet length E of the LTE system_l[P]The time length T of successful data transmission of the wireless network system_swThe time length T of successful data transmission of the LTE system_slAccess probability tau of the wireless network system_wThe length of time T of the data collision_cAnd the length δ of the slot, by the following equation:

calculating an access probability τ at which a total throughput of the LTE system and the wireless network system is maximized_lWherein, the

The above-mentioned

6. The method of claim 1, wherein the calculating a current back-off time window of the LTE system corresponding to the CQI value at the current time according to the transmission probability, the packet loss probability, the access probability, and the CQI value at the current time comprises:

according to the transmission probability q, the packet loss probability p and the access probability tau_lAnd the CQI value at the current time by the following formula:

W_CQI＝(16-CQI)·w

calculating a current back-off time window W of the LTE system corresponding to the CQI value at the current moment_CQIWherein w is a unitized back-off time window.

7. The method of claim 1, wherein the preset CQI value table further stores levels, each level corresponds to at least one CQI value, and the searching for the current modulation scheme, the current coding rate, and the current efficiency corresponding to the CQI value at the current time through the preset CQI value table comprises:

searching a current modulation mode, a current coding rate and a current efficiency corresponding to the CQI value at the current moment and a current layer level corresponding to the CQI value at the current moment through a preset CQI value table;

correspondingly, in the backoff time window, a positive integer is randomly selected as a backoff counter, the current backoff counter and the access probability are accessed to an unauthorized frequency band, and after the encoded data to be transmitted are transmitted through the unauthorized frequency band, the method further includes:

when the LTE system collides with the wireless network system, reducing the current layer level to a next layer level, and coding the data packet to be sent in a modulation mode corresponding to the next layer level to obtain first coded data to be sent;

selecting any one CQI value from a plurality of CQI values corresponding to the next layer number as a CQI value of the next moment, and calculating a next back-off time window of the LTE system corresponding to the CQI value of the next moment according to the transmission probability, the packet loss probability, the access probability and the CQI value of the next moment;

and randomly selecting a positive integer as a next backoff counter in the next backoff time window, accessing an unauthorized frequency band according to the next backoff counter and the access probability, and transmitting the first coded data to be transmitted to the user terminal through the unauthorized frequency band.

8. An apparatus for accessing an unlicensed frequency band, the apparatus comprising:

the encoding module is configured to search, through a preset CQI value table, a current modulation mode, a current encoding rate, and a current efficiency that correspond to the CQI value at the current time, and encode the data to be transmitted in the current modulation mode to obtain currently encoded data to be transmitted, where the preset CQI value table includes a CQI value, a modulation mode that corresponds to the CQI value, an encoding rate that corresponds to the CQI value, and an efficiency that corresponds to the CQI value;

a physical layer rate calculation module, configured to calculate a physical layer rate of the LTE system according to the current modulation scheme, the current coding rate, and the current efficiency;

the access probability calculation module is used for acquiring the physical layer rate of a wireless network system which is stored in advance, and calculating the access probability when the total throughput of the LTE system and the wireless network system is the maximum value according to the physical layer rate of the LTE system, the physical layer rate of the wireless network system, the number N of wireless network equipment in the wireless network system and other related parameters; wherein the other relevant parameters include: the method comprises the following steps of determining the length of a data packet of a wireless network system, the length of a data packet of an LTE system, the length of time for the wireless network system to successfully transmit data, the length of time for the LTE system to successfully transmit data, the length of data collision, the length of a time slot and the access probability of the wireless network system, wherein the wireless network system is a system using an unauthorized frequency band;

a backoff time window calculation module, configured to obtain a pre-stored transmission probability that a data packet is transmitted on a channel and a packet loss probability caused by a collision, and calculate a current backoff time window of the LTE system corresponding to the CQI value of the current time according to the transmission probability, the packet loss probability, the access probability, and the CQI value of the current time;

and the access module is used for randomly selecting a positive integer as a current backoff counter in the current backoff time window, accessing an unauthorized frequency band according to the current backoff counter and the access probability, and transmitting the coded data to be transmitted to the user terminal through the unauthorized frequency band.

9. An electronic device is characterized by comprising a processor, a communication interface, a memory and a communication bus, wherein the processor and the communication interface are used for realizing mutual communication by the memory through the communication bus;

a memory for storing a computer program;

a processor for implementing the method steps of any of claims 1 to 7 when executing a program stored in the memory.

10. A computer-readable storage medium, characterized in that a computer program is stored in the computer-readable storage medium, which computer program, when being executed by a processor, carries out the method steps of any one of claims 1 to 7.