CN111405679A - Random access control method for Internet of things based on time advance - Google Patents

Random access control method for Internet of things based on time advance Download PDF

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CN111405679A
CN111405679A CN202010197131.9A CN202010197131A CN111405679A CN 111405679 A CN111405679 A CN 111405679A CN 202010197131 A CN202010197131 A CN 202010197131A CN 111405679 A CN111405679 A CN 111405679A
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terminal
access
preamble
random access
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CN111405679B (en
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任光亮
余砚文
王奇伟
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Xidian University
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    • H04—ELECTRIC COMMUNICATION TECHNIQUE
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Abstract

The invention discloses an access control method based on time advance, which mainly solves the problem that in the prior art, when a large number of intelligent terminals simultaneously apply for random access, conflict is generated due to the fact that lead code sequence resources compete violently. The implementation scheme is as follows: 1) when the terminal sends a preamble sequence to apply for random access, the base station judges the area where the terminal is located according to the time advance and calculates the optimal access probability factor of each area; 2) after receiving the random access response of the base station, the terminal realizes access control according to the allowed access probability of the area; 3) and after terminals which are not allowed to access and terminals which fail to access are randomly backed off for a period of time, re-applying for a random access process. According to the method, the optimal access probability factor is combined according to different time leads, so that the utilization rate of the lead code sequence resource of the system is maximized, the average time delay of terminal access is reduced, and the system throughput is improved; the method can be used for controlling the random access process of the ground Internet of things.

Description

Random access control method for Internet of things based on time advance
Technical Field
The invention belongs to the technical field of communication, and further relates to an access technology of a ground Internet of things, in particular to an Internet of things random access control method based on time advance; the method can be used for the ground Internet of things with a large number of terminals simultaneously applying for access resources.
Background
The ground internet of things generally covers a large number of intelligent terminals, such as intelligent distance measurement, human health monitoring and safety monitoring, and 78 billion intelligent terminals are expected to be available in 2021. When a large number of intelligent terminals are activated simultaneously, because the resources allowed to access are limited, a plurality of terminals contend for the same access resource, and therefore, in order to effectively avoid the occurrence of a collision, an access control means is usually adopted for the terminals to ensure the service quality.
At present, the research on access control at home and abroad is based on the Access Class Barring (ACB) scheme of 3GPP, that is, the system allows access probability through broadcasting, each terminal generates a random number, if the random number is less than the probability, the access is allowed, otherwise, the access is not allowed.
Zehua Wang et al, in the article "Optimal Access Class Barring for Stationarymachine Type Communication With Timing Advance Information" (IEEETransactions on Wireless Communications, vol.14, No.10, pp.5374-5387, Oct.2015), propose an Access control method based on time Advance, which maximizes throughput by deriving a functional relationship between system throughput and Access probability to obtain an Optimal Access probability, and further solve the problem of terminal contention for Access resources, however, the disadvantage of this method is that the same Access probability is broadcast for all terminals in a cell, and thus the control accuracy is not high.
Chong Di et al, in the article "L arrival Automata based Access Class BarringScheme for Massive Random Access in Machine-to-Machine Communications" (IEEEInternet of these Journal, vol.6, No.4, pp.6007-6017, Aug.2019), analyzed the relationship between the number of newly arrived and applied retransmission devices and the Access probability in the current timeslot, and estimated the number of the most likely terminals to be applied for Access in the current timeslot by a search algorithm, thereby obtaining the Access probability in the next timeslot.
Taehon Kim et al, in the paper "An Enhanced Random Access Scheme With spatial group Based Reusable Preamble in Cellular M2M Networks" (IEEEcommunications L, vol.19, No.10, pp.1714-1717, Oct.2015), propose to divide the cell covered area into several cells according to the time advance, each cell can multiplex the same Preamble sequence, so as to reduce the collision generated when the devices of two different cells apply for the same Preamble sequence.
Disclosure of Invention
The invention aims to provide a random access control method of the internet of things based on the time advance, which aims to solve the problem of conflict of simultaneously applying for random access resources by a large number of intelligent terminals, improve the utilization rate of system resources and reduce the average access delay of the intelligent terminals.
The idea for realizing the invention is as follows: firstly, multiplexing of the same lead code sequence resource by different equipment terminals is realized through the time advance, and the utilization rate of system resources is improved; then, determining the area where the intelligent terminal is located according to the time advance; and finally, determining the optimal access probability factor by constructing a functional relation between the number of the allowed access devices and the throughput. The invention combines the optimal access probability factor according to the difference of the time advance, thereby maximizing the utilization rate of the lead code sequence resource of the system, reducing the average time delay of the terminal access and improving the system throughput.
The invention realizes the aim as follows:
(1) the system broadcast allows the terminal equipment registered in the Internet of things system to carry out random access, the terminal applying for random access keeps an interception state, and system broadcast information is received;
(2) in the current time slot, a terminal applying for access randomly selects one of L preamble sequences specified by L TE protocol and sends the selected preamble sequence to a base station;
(3) the base station detects the received preamble signal and determines whether the preamble in the current time slot is multiplexed:
(3a) the base station carries out correlation calculation on the received preamble signal and L locally known preamble sequences to obtain a correlation coefficient E of the two preamble signalscorr(ii) a Determining the serial number of the received lead code according to the magnitude relation between the correlation coefficient and the detection threshold value;
(3b) let the first peak position of multiple detection signals appearing on the multi-path propagation time axis be t1The last peak position is t2σ is the multipath delay spread; if t is present2-t1If not more than sigma, judging that the lead code is not multiplexed; otherwise, the lead code is judged to be multiplexed by the two terminals;
(4) the base station estimates the time advance T corresponding to the lead code signal sent by the terminalADividing the cell into phi annular regions with equal intervals according to the multipath delay spread sigma, and respectively calculating the optimal access probability of all the regions
Figure BDA0002418027330000031
Wherein
Figure BDA0002418027330000032
Representing the optimal access probability of the region with the region number of x;
(5) the base station returns a random access response RAR to the terminal, and the response at least comprises the preamble sequence number η selected by the terminal and the time advance TAUplink scheduling authorization theta and the area number chi of the uplink scheduling authorization theta; when the preamble is not multiplexed, only one access response RAR is returned, and when the preamble is multiplexed by two terminals, two access responses RAR are required to be returned simultaneously;
(6) the terminal keeps the interception state, and if the received Random Access Response (RAR) is TAValue and terminal's own reference timing advance
Figure BDA0002418027330000033
If the values are the same, receiving the response and correspondingly adjusting the uplink transmission time according to the time lead; otherwise, discarding the response;
(7) the terminal obtains the random access response from the received random access responseIts affiliated area number χ, thereby obtaining the corresponding access probability
Figure BDA0002418027330000034
Meanwhile, the terminal randomly generates a random number rho if
Figure BDA0002418027330000035
The terminal continues to execute the step (8), otherwise, the step (10) is executed;
(8) the terminal transmits a Radio Resource Control (RRC) sublayer message to the base station by adopting a hybrid automatic retransmission mechanism through a Physical Uplink Shared Channel (PUSCH);
(9) after receiving the message, the base station performs contention resolution and broadcasts a contention resolution result, the terminal which succeeds in contention resolution is successfully accessed, and the terminal which fails in contention resolution executes the step (10);
(10) the terminal adopts a back-off mechanism to back off randomly for a period of time, and the transmitting power is increased to apply for access again when the system broadcast carries out random access.
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FIG. 1 is a schematic diagram of an application scenario of the present invention;
fig. 2 is a simulation diagram comparing the average access delay performance of the access mechanism employed in the present invention with the existing access mechanism;
FIG. 3 is a simulation graph comparing the total time taken for access completion of the access mechanism employed in the present invention with that of the existing access mechanism;
FIG. 4 is a simulation diagram comparing the number of devices applying for access and the number of devices successfully accessing in a plurality of areas without access control according to the present invention;
fig. 5 is a simulation diagram comparing the number of devices applying for access and the number of devices successfully accessing in a plurality of areas with access control according to the present invention.
Detailed Description
The invention has the following implementation steps:
step 1, the system broadcasts the terminal equipment which allows the on-line registration to carry out the random access, the terminal applying the random access keeps the interception state, and the system broadcast information is received:
l TE specifies 64 mutually orthogonal preamble sequences for terminal equipment to select, wherein the sequences are divided into non-competitive preamble sequences and competitive preamble sequences, the non-competitive preamble sequences are generally used for the communication process between people, and the competitive preamble sequences are generally used for the communication process of machines.
Step 2, in the current time slot, the terminal applying for access randomly selects a preamble from the L preamble sequences of L TE, and sends the preamble to the base station:
l TE has two uplink channels for requesting access, one is physical random access channel PRACH mainly used for transmitting preamble sequence, the other is physical uplink shared channel PUSCH mainly used for transmitting signaling information, the working bandwidth of PRACH is the bandwidth of 6 resource blocks, namely 6x180kHz, from the aspect of frequency domain, the PRACH occupies a random access time slot RAO, and the time range occupied by a random access time slot RAO is 1ms to 20ms according to different configuration parameters of the system.
Step 3, the base station detects the preamble sequence signal sent by the terminal, and determines whether the preamble in the current time slot is multiplexed:
(3a) calculating a correlation coefficient E between the received preamble signal and L preamble sequences specified by a long term evolution L TE protocol according to the following formulacorr：
Figure BDA0002418027330000041
Wherein x (i) is the i-th symbol in the received preamble sequence, y (i) is the i-th symbol in the locally known preamble sequence, NZCThe total number of symbols contained in the preamble sequence;
determining the serial number of the received lead code according to the magnitude relation between the correlation coefficient and the detection threshold value; since different preamble sequences are orthogonal to each other, if the correlation coefficient between the received preamble sequence and a local preamble sequence is greater than the detection threshold, the preamble sequence value sent by the terminal, that is, the sequence number to which the received preamble belongs, can be determined. The detection threshold is a value set according to system-related parameters, and the value is related to parameters such as specific preamble length, signal-to-noise ratio, and the like, and is usually set to be above 0.3.
(3b) Because of the multipath propagation mode, the peak values of a plurality of detection signals appear on the time axis, and the first peak position of the plurality of detection signals appearing on the time axis is t1The last peak position is t2σ is the multipath delay spread; if t is present2-t1Sigma is less than or equal to indicate that a plurality of detected signals are caused by scattering diffraction of the same signal, so that the lead code is determined not to be multiplexed and only corresponds to a time advance; otherwise, explain t2If the signal appearing at the position is the same lead code sent by another terminal, the lead code is determined to be multiplexed by the two terminals and corresponds to two time lead amounts;
step 4, the base station estimates the time advance T of each terminalADividing the cell into phi annular regions with equal intervals according to the multipath delay spread sigma; further calculating the optimal access probability of all areas
Figure BDA0002418027330000051
Wherein
Figure BDA0002418027330000052
Representing the best access probability of the region with the region number χ. In this embodiment, taking Φ as an example 4, the specific calculation steps are as follows:
(4a) calculating an interference interval:
＝c·σ，
wherein c is the speed of light, and σ is the multipath delay spread;
(4b) calculating the separation interval d:
Figure BDA0002418027330000053
dividing the cell into four regions along the cell radius at intervals of d, each region being denoted as Λ1、Λ2、Λ3、Λ4Wherein Λ1Is a circular area, Λ2、Λ3、Λ4Are respectively and Λ1The region numbers chi of the annular regions from near to far are respectively 1, 2, 3 and 4;
(4c) in the current time slot, region Λ1M for random access, M for allowed access, Λ2The number of terminals applying for random access is N, the number of allowed accesses is N, and the area Λ3The number of terminals applying for random access is K, the number of allowed accesses is K, and the region Λ4The number of terminals applying for random access is R, and the number of allowed access is R; the total number of devices allowed to access is m + n + k + r,
(4d) computing system throughput T:
T(m,n,k,r)＝T0+T1+T2+T3+T4
wherein, T0Represents the system throughput when a certain preamble is selected by only one terminal; t is1Indicating that a certain preamble belongs to the area Λ1And another belongs to the area Λ3Or Λ4When the devices are simultaneously selected, area Λ1A throughput of (1); t is2Indicating that a certain preamble belongs to the area Λ2And another belongs to the area Λ4When the devices are simultaneously selected, area Λ2A throughput of (1); t is3Indicating that a certain preamble belongs to the area Λ3And another belongs to the area Λ1When the devices are simultaneously selected, area Λ3A throughput of (1); t is4Indicating that a certain preamble belongs to the area Λ4And another belongs to the area Λ1Or Λ2When the devices are simultaneously selected, area Λ4A throughput of (1); their calculation formula is as follows:
Figure BDA0002418027330000061
Figure BDA0002418027330000062
Figure BDA0002418027330000063
Figure BDA0002418027330000064
Figure BDA0002418027330000065
wherein L is the number of preambles;
(4e) obtaining the optimal access probability of each area according to the following formula
Figure BDA0002418027330000066
Figure BDA0002418027330000067
Wherein p is1、p2、p3And p4Respectively representing the allowed access probability of four regions, and respectively satisfying the relation m ═ Mp1、n＝Np2、k＝Kp3And r ═ Rp4；
Step 5, the base station returns a random access response RAR to the terminal i, the response at least comprises the following information, the lead code serial number η selected by the ith terminaliTime advance of ith terminal
Figure BDA0002418027330000068
Uplink scheduling grant theta of ith terminaliRegion number χ to which ith terminal belongsi(ii) a When the preamble is not multiplexed, only return
Figure BDA0002418027330000069
When the preamble is multiplexed by two terminals, it needs to return simultaneously
Figure BDA00024180273300000610
And
Figure BDA00024180273300000611
the acquisition χ is calculated as followsi；
(5a) According to the advance of time
Figure BDA0002418027330000071
Calculating the distance gamma of the terminal i from the base stationi：
Figure BDA0002418027330000072
γi＝c·ti；
Therein, 16TsFor synchronous granularity, T s1/30720ms, c is the speed of light.
(5b) According to the distance gammaiCalculating the region number χ of the terminal i according to the following formulai：
Figure BDA0002418027330000073
Obtained by the same principle, xi 1Hexix-i 2；
Step 6, the terminal keeps the interception state, if the time advance value in the received random access response RAR and the reference time advance of the terminal
Figure BDA0002418027330000074
If the values are the same, the random access response is sent to the terminal and received, otherwise, the response is discarded. After receiving the random access response, the terminal correspondingly adjusts the time of uplink transmission according to the time advance.
Step 7, the terminal obtains the area number of the random access response from the received random access response, thereby obtaining the corresponding access probability
Figure BDA0002418027330000075
Meanwhile, the terminal randomly generates a random number rho if
Figure BDA0002418027330000076
The terminal continues to step 8, otherwise, step 10 is performed.
Step 8, the terminal transmits a radio resource control RRC sublayer message to the base station:
the RRC sublayer message is specified by the 4G protocol, and the terminal sends the message to the base station after receiving the random access response; the terminal transmits the connection request information through the PUSCH channel, and in order to ensure that the connection request information is successfully transmitted to the base station, a hybrid automatic repeat request mechanism is adopted, that is, if a feedback signal is not received within a certain time, the connection request signal is transmitted again.
Step 9, after receiving the signal, the base station performs contention resolution and broadcasts a contention resolution result:
the base station feeds back the result of the connection request signal to the terminal, if the terminal still does not receive the feedback signal of the base station after the terminal finishes the self conflict resolution countdown, the terminal which competes for the lead code resource fails, and the failed terminal executes the step 10; if the feedback signal is received, it indicates that the terminal competes for the preamble resource this time, and directly enters step 11.
Step 10, the terminal retreats for a period of time, and random access is performed again when the system broadcasts:
the terminal randomly backs off for a period of time to reapply for access, and the transmission power is increased when the selected preamble sequence is retransmitted next time. The back-off method is as follows:
(10a) if the terminal withdraws due to the failure of competition, the withdrawal time is tau1：
Figure BDA0002418027330000081
Wherein N iscolFor the number of terminal backoffs, U (-) represents the compliance interval [ ·]Uniformly distributed therein.
(10b) If the terminal is retreated due to not allowing access, the retreating time is tau2：
τ2＝U(1,10·Ncol)，
Wherein N iscolFor the number of terminal backoffs, U (-) represents the compliance interval [ ·]Uniformly distributed therein.
And 11, stopping the random access process after the access is successful.
The effect of the present invention will be further explained by the simulation experiment of the present invention.
1. Simulation conditions are as follows:
the simulation experiment of the invention uses Matlab R2014a simulation software, the simulation model is as shown in fig. 1, the radius of the cell is set to be 500 meters, the interference interval is 250m, d is 125m, sigma is 0.416 mu s, and one time slot T is setsThe service model adopts a L TE service burst model, where 0.5ms is used, and the preamble number L is 64, and the specific steps are as follows:
Figure BDA0002418027330000082
wherein Beta (α) is Beta function, α is 3, β is 4, TA＝50ms。
2. Simulation content and result analysis thereof:
simulation 1, referring to fig. 2, a simulation graph comparing average access delay performance of an access mechanism adopted by the present invention with that of an existing access mechanism, a simulation comparing random access without time advance and random access with time advance used in the existing related art, and a random access combining cell division and time advance adopted in the present invention, average access delay performance under three random access mechanisms, the result is shown in a curve in fig. 2. Wherein, the horizontal axis of fig. 2 represents the total number of devices waiting for access in the system, the vertical axis represents the total time spent on successful access of each terminal on average, the time delay of terminal access represents the time spent from the first application access to the final successful access of the terminal, and the unit is the number of time slots; as can be seen from fig. 2, the average delay of the scheme without the timing advance mechanism is larger than that of the scheme with the timing advance mechanism, and when the number of terminals is smaller, the average delay increases more slowly, but when the number of terminals is larger, the average delay increases more quickly, and after the cell division and the timing advance mechanism are combined, the average delay is smaller than that of the other two schemes and almost linearly increases.
Simulation 2, referring to fig. 3, comparing the total time performance spent on access completion of the access mechanism adopted by the invention and the existing access mechanism with a simulation diagram; compared with the random access without time advance, the random access with time advance and the random access combining the cell division and the time advance adopted in the invention, the simulation shows the total time spent by the three access mechanisms to complete the access process, and the result is shown in a curve in fig. 3. Wherein the horizontal axis of fig. 3 represents the total number of devices waiting for access in the system, and the vertical axis represents the total time taken by all terminals to access successfully, and the unit is the number of slots. As can be seen from fig. 3, when the number of terminals is small, the total access completion time of the time lead-free access mechanism scheme and the time lead-free access mechanism scheme is almost the same, and when the number of terminals is large, the access completion time of the time lead-free access mechanism scheme is longer than that of the time lead access mechanism scheme, and the total access completion time of the access mechanism scheme combining cell partition and time lead is the least and almost shows a linear increase trend.
Simulation 3, referring to fig. 4, comparing the number of devices applying for access and the number of devices successfully accessed in a plurality of areas without access control with a simulation diagram; comparing the number of devices applying for access and the number of devices successfully accessed in a plurality of areas without access control in the invention by simulation, wherein the result is shown as a curve in fig. 4; wherein the horizontal axis of fig. 4 represents the time of terminal access, the unit is time slot, the vertical axis represents the number of devices accessed, as can be seen from fig. 4, the number of terminals in area 4 is the largest, the number of terminals in area 1 is the smallest, in the first 200 time slots, the number of terminals successfully accessed is almost 0, and after the 250 th time slot, a small number of terminals are successfully accessed.
Simulation 4, referring to fig. 5, comparing the number of devices applying for access and the number of devices successfully accessed in a plurality of areas with access control in the invention with a simulation diagram; comparing the number of devices applying for access and the number of devices successfully accessed in the multiple areas with access control in the invention by simulation, the result is shown as a curve in fig. 5; as can be seen from fig. 5, after access control is adopted, the number of terminals accessed in each area is greatly different, and in the first 150 time slots, the number of terminal devices in areas 1, 2, and 4 are mainly accessed, and since preamble sequences can be multiplexed, the number of terminals successfully accessed is also large, and in the last 200 time slots, the number of terminals successfully accessed is mainly accessed in area 3, and since the number of terminals contended is small, the number of terminals successfully accessed is also large.
The simulation analysis proves the correctness and the effectiveness of the method provided by the invention.
The invention has not been described in detail in part of the common general knowledge of those skilled in the art.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.

Claims (7)

1. A random access control method of the Internet of things based on time advance is characterized by comprising the following steps:
(1) the system broadcast allows the terminal equipment registered in the Internet of things system to carry out random access, the terminal applying for random access keeps an interception state, and system broadcast information is received;
(2) in the current time slot, a terminal applying for access randomly selects one of L preamble sequences specified by L TE protocol and sends the selected preamble sequence to a base station;
(3) the base station detects the received preamble signal and determines whether the preamble in the current time slot is multiplexed:
(3a) the base station carries out correlation calculation on the received preamble signal and L locally known preamble sequences to obtain a correlation coefficient E of the two preamble signalscorr(ii) a Determining the serial number of the received lead code according to the magnitude relation between the correlation coefficient and the detection threshold value;
(3b) let the first peak position of multiple detection signals appearing on the multi-path propagation time axis be t1The last peak position is t2σ is the multipath delay spread; if t is present2-t1If not more than sigma, judging that the lead code is not multiplexed; otherwise, the lead code is judged to be multiplexed by the two terminals;
(4) the base station estimates the time advance T corresponding to the lead code signal sent by the terminalADividing the cell into phi annular regions with equal intervals according to the multipath delay spread sigma, and respectively calculating the optimal access probability of all the regions
Figure FDA0002418027320000011
Wherein
Figure FDA0002418027320000012
Representing the optimal access probability of the region with the region number of x;
(5) the base station returns a random access response RAR to the terminal, and the response at least comprises the preamble sequence number η selected by the terminal and the time advance TAUplink scheduling authorization theta and the area number chi of the uplink scheduling authorization theta; when the preamble is not multiplexed, only one access response RAR is returned, and when the preamble is multiplexed by two terminals, two access responses RAR are required to be returned simultaneously;
(6) the terminal keeps the interception state, and if the received Random Access Response (RAR) is TAValue and terminal's own reference timing advance
Figure FDA0002418027320000013
If the values are the same, receiving the response and correspondingly adjusting the uplink transmission time according to the time lead; otherwise, discarding the response;
(7) the terminal obtains the region number x of the random access response from the received random access response so as to obtain the corresponding access probability
Figure FDA0002418027320000021
Meanwhile, the terminal randomly generates a random number rho if
Figure FDA0002418027320000022
The terminal continues to execute the step (8), otherwise, the step (10) is executed;
(8) the terminal transmits a Radio Resource Control (RRC) sublayer message to the base station by adopting a hybrid automatic retransmission mechanism through a Physical Uplink Shared Channel (PUSCH);
(9) after receiving the message, the base station performs contention resolution and broadcasts a contention resolution result, the terminal which succeeds in contention resolution is successfully accessed, and the terminal which fails in contention resolution executes the step (10);
(10) the terminal adopts a back-off mechanism to back off randomly for a period of time, and the transmitting power is increased to apply for access again when the system broadcast carries out random access.
2. The method of claim 1, wherein: correlation coefficient E in step (3a)corrCalculated according to the following formula:
Figure FDA0002418027320000023
wherein x (i) is the i-th symbol in the received preamble sequence, y (i) is the i-th symbol in the locally known preamble sequence, NZCThe total number of symbols included in the preamble sequence.
3. The method of claim 1, wherein: the detection threshold in step (3a) is a value set according to system-related parameters, and when a correlation coefficient between a received preamble sequence and a certain local preamble sequence is greater than the detection threshold, it is determined that a sequence number of the local preamble sequence is a sequence number to which a preamble transmitted by the terminal belongs.
4. The method of claim 1, wherein: in the step (4), the cell is divided into phi annular regions with equal intervals according to the multipath delay spread sigma, and the method specifically comprises the following steps:
(4a) calculating an interference interval:
＝c·σ，
wherein c is the speed of light, and σ is the multipath delay spread;
(4b) calculating the separation interval d:
Figure FDA0002418027320000031
dividing the cell into phi regions along the cell radius at intervals of d, which are respectively recorded as Λ1、Λ2…Λχ…ΛφWherein χ is not less than 1 and not more than φ, and χ is an integer.
5. The method of claim 1, wherein: the optimal access probability of the region with the region number of x in the step (4)
Figure FDA0002418027320000032
Wherein x is more than or equal to 1 and less than or equal to phi, and is calculated according to the following steps:
(4c) in the current time slot, region ΛχThe number of terminals applying for random access is GχThe number of allowed accesses is gχ；
(4d) Computing system throughput T:
Figure FDA0002418027320000033
wherein, T0Represents the system throughput when a certain preamble is selected by only one terminal; t isχIndicating that a certain preamble belongs to the area ΛχAnd another stationRegion Λ when devices belonging to regions not adjacent thereto are simultaneously selectedχA throughput of (1);
(4e) determining the optimal access probability of each region according to the following formula:
Figure FDA0002418027320000034
wherein p isχRepresents the allowed access probability of the region χ and satisfies the relation gχ＝Gχpχ。
6. The method of claim 1, wherein: the area number x belonging to the step (5) is calculated by the base station according to the following steps;
(5a) according to the time advance TACalculating the distance gamma of the terminal from the base station:
γ＝c·(TA·16Ts)；
therein, 16TsDenotes the synchronization granularity, Ts1/30720ms, c is the speed of light;
(5b) calculating the area number χ of the terminal according to the distance γ and the separation distance d according to the following formula:
Figure FDA0002418027320000041
7. the method of claim 1, wherein: the back-off mechanism adopted by the terminal in the step (10) is as follows:
(10a) if the terminal withdraws due to the failure of competition, the withdrawal time is tau1：
Figure FDA0002418027320000042
(10b) If the terminal is retreated due to not allowing access, the retreating time is tau2：
τ2＝U(1,10·Ncol)，
Wherein N iscolFor the number of terminal backoffs, U (-) represents the compliance interval [ ·]Uniformly distributed therein.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111970765A (en) * 2020-08-10 2020-11-20 杭州电子科技大学 Large-scale terminal access method and system
CN113329445A (en) * 2021-05-28 2021-08-31 江苏集萃深度感知技术研究所有限公司 NB-IoT-based street lamp control access method
WO2022127806A1 (en) * 2020-12-15 2022-06-23 华为技术有限公司 Wireless communication method and apparatus

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2408253A1 (en) * 2010-07-13 2012-01-18 Alcatel Lucent Method for random access to a wireless or mobile communication network, and corresponding transceiver equipment
CN106102182A (en) * 2016-06-07 2016-11-09 北京交通大学 Nonopiate accidental access method
CN107371126A (en) * 2017-08-21 2017-11-21 西安电子科技大学 Accidental access method based on FDD LTE networks
CN108811119A (en) * 2017-05-05 2018-11-13 华为技术有限公司 Accidental access method, equipment and system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2408253A1 (en) * 2010-07-13 2012-01-18 Alcatel Lucent Method for random access to a wireless or mobile communication network, and corresponding transceiver equipment
CN106102182A (en) * 2016-06-07 2016-11-09 北京交通大学 Nonopiate accidental access method
CN108811119A (en) * 2017-05-05 2018-11-13 华为技术有限公司 Accidental access method, equipment and system
CN107371126A (en) * 2017-08-21 2017-11-21 西安电子科技大学 Accidental access method based on FDD LTE networks

Non-Patent Citations (6)

* Cited by examiner, † Cited by third party
Title
CHONG DI等: "Learning Automata-Based Access Class Barring Scheme for Massive Random Access in Machine-to-Machine Communications", 《IEEE INTERNET OF THINGS JOURNAL》 *
HAN SEUNG JANG等: "A Preamble Collision Resolution Scheme via Tagged Preambles for Cellular IoT M2M Communications", 《IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY》 *
TAEHOON KIM等: "An Enhanced Random Access Scheme With Spatial Group Based Reusable Preamble Allocation in Cellular M2M Networks", 《IEEE COMMUNICATIONS LETTERS》 *
ZEHUA WANG等: "Optimal Access Class Barring for Stationary Machine Type Communication_Devices_With_Timing Advance Information", 《IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS)》 *
刘文燕: "窄带物联网中大规模接入方法研究", 《中国优秀硕士学位论文全文数据库》 *
张继荣等: "基于终端分组的非正交随机接入资源分配方案", 《计算机科学》 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111970765A (en) * 2020-08-10 2020-11-20 杭州电子科技大学 Large-scale terminal access method and system
CN111970765B (en) * 2020-08-10 2022-05-31 杭州电子科技大学 Large-scale terminal access method and system
WO2022127806A1 (en) * 2020-12-15 2022-06-23 华为技术有限公司 Wireless communication method and apparatus
CN113329445A (en) * 2021-05-28 2021-08-31 江苏集萃深度感知技术研究所有限公司 NB-IoT-based street lamp control access method

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