Frequency portal based cognitive wireless communication terminal pairing method

Abstract

The application discloses a frequency entry-based cognitive wireless communication terminal pairing method, which comprises the following steps: calculating a current channel occupancy rate, and then calculating the overall occupancy of the working frequency band according to the current channel occupancy; calculating the number of optimal frequency entries; selecting a frequency entry set; the method selects available frequencies according to spectrum sensing and decision results in the working frequency band of a terminal device, generates a specific frequency entry set, and pairs terminals according to the generated frequency entry set, so that efficient cognitive wireless communication terminal pairing can be realized; and moreover, the frequency entry set generated each time is based on real-time spectrum sensing and decision results, so that the method has stronger robustness compared with a terminal pairing method based on a public control channel.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, specifically relating to a cognitive wireless communication terminal pairing method based on frequency entry. Background Technology

[0002] Cognitive wireless communication terminals can adapt to the external wireless environment by learning and understanding, adaptively adjusting their internal communication mechanisms and changing specific wireless operating parameters (such as power, carrier modulation, and coding) in real time. They can autonomously find and use idle spectrum, helping users select the best and most suitable service for wireless transmission. They can even delay or actively initiate transmission based on existing or upcoming wireless resources. Due to the dynamic characteristics of cognitive wireless communication terminals in terms of transmission frequency, pairing between terminals faces more difficulties compared to pairing other types of communication terminal devices (such as Bluetooth devices). Existing cognitive wireless communication terminal pairing schemes are mainly divided into two types: terminal pairing schemes based on the Common Control Channel (CCC) and terminal pairing schemes based on Channel Hopping (CH).

[0003] The core idea of ​​a terminal pairing scheme based on a common control channel is to select a fixed common control channel. When two cognitive wireless communication terminals need to pair, they exchange control information on this fixed common control channel to complete the pairing process. Because a fixed control channel is introduced, theoretically, cognitive wireless communication terminals can complete the pairing process quickly. However, in reality, the terminal pairing scheme based on a common control channel is difficult to implement for the following reasons: 1. It is very difficult to select a suitable fixed common control channel to meet the communication needs of all cognitive wireless communication terminals; 2. Fixedly allocated common control channels are susceptible to interference and congestion attacks, have poor robustness, and may require a longer waiting time for the common control channel to become idle, which contradicts the core idea of ​​cognitive wireless communication; 3. Because the channel capacity of the common control channel is limited, the number of terminal pairings based on the common control channel is limited, resulting in poor scalability.

[0004] The core idea of ​​the terminal pairing scheme based on frequency hopping sequences is that each cognitive wireless communication terminal generates a specific frequency hopping sequence based on its own spectrum sensing and decision-making results, and performs frequency hopping according to the time slot based on this generated frequency hopping sequence. This type of pairing scheme makes full use of the sensing capabilities of cognitive wireless communication terminals, and the frequency hopping sequence generated each time is different. Compared with the terminal pairing scheme based on the common control channel, it has stronger robustness. However, as the operating frequency band of hardware continues to expand, the frequency hopping sequence generated by the terminal device gradually increases, and the process of each terminal pairing also gradually increases. Because the terminal pairing time is too long, it seriously affects the data transmission rate of cognitive wireless communication terminals.

[0005] Based on the aforementioned technical problems in the existing technology, this invention proposes a cognitive wireless communication terminal pairing method based on frequency entry. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a cognitive wireless communication terminal pairing method based on frequency entry.

[0007] The present invention adopts the following technical solution:

[0008] A cognitive wireless communication terminal pairing method based on frequency entry, comprising:

[0009] Step 1: Calculate the current channel occupancy rate. Utilize the terminal's own sensing and decision-making capabilities to obtain the channel occupancy status of the current frequency band, and then calculate the overall occupancy status of the working frequency band based on the current channel occupancy status.

[0010] Step 2: Calculate the optimal number of frequency entry points. Establish a mathematical model based on the relationship between average terminal pairing time, channel occupancy rate, and the number of frequency entry points. Analyze the mathematical model to find the number of frequency entry points that minimizes the average terminal pairing time under a given channel occupancy rate.

[0011] Step 3: Select the frequency entry set. Based on the optimal number of frequency entry points, the main terminal device selects a corresponding number of frequencies from the available channel set as the frequency entry set for subsequent terminal pairing; and selects a corresponding number of frequencies from the total channel set of the terminal device as the frequency entry set for subsequent terminal pairing.

[0012] Furthermore, in step 1:

[0013] The frequency band in which the cognitive wireless communication terminal operates is divided into N non-overlapping channels, where N > 1. After spectrum sensing, the average power P of each channel is obtained. i i∈[1,N] and peak power After sorting the average power of N channels from smallest to largest, select the top... The decision threshold is calculated using a set of values, with the initial threshold denoted as . in:

[0014]

[0015]

[0016] Among them, P′ j Let f represent the j-th average power value after sorting, where f is a constant factor. The decision is made on N channels based on a decision threshold, and the decision criteria are as follows:

[0017]

[0018] in, This represents the channel state of the i-th channel in the l-th round of decision, where 1 indicates the channel is idle and available, and 0 indicates the channel is occupied and unavailable. Let be the peak power of the i-th channel. This is the decision threshold calculated in round l-1. Statistics are compiled after the first round of decisions. Number of channels like according to Calculate the new threshold for channel average power And proceed to the next round of judgment; if The verdict has concluded, and the final outcome is... One idle channel and One occupied channel;

[0019] Therefore, the current channel occupancy rate of the operating frequency band can be calculated as follows:

[0020]

[0021] Furthermore, in step 2:

[0022] Let P be the probability that channel k is occupied. ko Since the probability of each channel being occupied is independent and identically distributed, we have:

[0023] P 1o =P 2o =...=P No =P o ......(5),

[0024] The number of channels selected by the cognitive wireless communication terminal is n, where n∈[1,N]. When all channels selected during the terminal pairing process are occupied, the terminal waits for T. w =nT0 time, continue searching for an available channel in the selected channels, where T0 is the shortest time required for the terminal device to exchange control information. The probability that the cognitive wireless communication terminal can find an available channel is:

[0025]

[0026] Among them, P fail This represents the probability that all channels are occupied. After substituting into equation (5), P fail =P o n The probability that the terminal finds a usable channel only on the Lth attempt is:

[0027] P L =P fail L-1 ×P succ =P o n(L-1) ×(1-P o n )......(7),

[0028] Among them, P o n(L-1) To make P fail =P o n After substituting the results, when an available channel is found only on the Lth attempt, the time required for terminal pairing is:

[0029] T L = (L-1)T w +T M ......(8),

[0030] Among them, T M To determine the maximum time required for terminal pairing under the condition that at least one channel is available, the average terminal pairing time when a cognitive wireless communication terminal selects n channels for terminal pairing is:

[0031]

[0032] Where the expectation of L is:

[0033]

[0034] According to equations (7) and (8), we have:

[0035]

[0036] According to equations (8) and (9), the pairing time corresponding to different frequencies of inlets is:

[0037]

[0038] Let T M =n,T w =max(T) M ) = N, T E(n, P) o )for:

[0039]

[0040] The current channel occupancy rate P of the operating frequency band is obtained through spectrum sensing and decision-making. o ;

[0041] Calculate the average terminal pairing time corresponding to the number of frequency inlets according to formula (11), and select the number of frequency inlets that minimizes the average terminal pairing time as the optimal number of frequency inlets.

[0042] Furthermore, in step 3:

[0043] Each cognitive wireless communication terminal maps each channel to N tags. Each cognitive wireless communication terminal selects channels from the N tags in sequence as the frequency entry for this terminal pairing based on the estimated optimal number of frequency entry points.

[0044] Furthermore, in step 1, the channel occupancy of the current operating frequency band is estimated in real time using the combined sensing and decision information.

[0045] Furthermore, in step 3, the frequency entry points are selected sequentially from the total set.

[0046] The beneficial effects of this invention are:

[0047] The cognitive wireless communication terminal pairing method based on frequency entry points described in this invention selects available frequencies within the operating frequency band of the terminal device based on spectrum sensing and decision-making results to generate a specific set of frequency entry points. Terminal pairing is then performed based on the generated set of frequency entry points. Since the size of the frequency entry point set is smaller than the size of the available channel set, the frequency hopping sequence generated based on the frequency entry point set is shorter than that of existing terminal pairing methods based on frequency hopping sequences. This enables efficient cognitive wireless communication terminal pairing. Furthermore, the frequency entry point set generated for each terminal pairing is based on real-time spectrum sensing and decision-making results, thus exhibiting stronger robustness compared to terminal pairing methods based on common control channels. Attached Figure Description

[0048] Figure 1 This is a flowchart of a cognitive wireless communication terminal pairing method based on frequency entry in an embodiment of the present invention;

[0049] Figure 2 This is a flowchart of the channel occupancy estimation method in an embodiment of the present invention;

[0050] Figure 3 This is a comparison chart of pairing time between embodiments of the present invention and other solutions under the same environmental conditions. Detailed Implementation

[0051] To better understand the above-mentioned objectives, features and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0052] Example

[0053] like Figure 1-2 As shown, the cognitive wireless communication terminal pairing method based on frequency entry includes:

[0054] Step 1: Calculate the current channel occupancy rate;

[0055] Step 1.1: Each terminal device senses its surrounding spectrum environment and obtains the average power and peak power of each channel in the current time period. The average power and peak power of the i-th channel are respectively expressed as: Where N is the total number of channels, and after sorting the average power of the N channels from smallest to largest, the top... The decision threshold is calculated using a set of values, with the initial threshold denoted as . in:

[0056]

[0057]

[0058] Among them, P′ j This represents the j-th average power value after sorting, where f is a constant factor;

[0059] Step 1.2: Perform iterative decision-making to obtain the channel state. Make decisions on N channels based on a decision threshold, calculated using the following formula:

[0060]

[0061] in, This represents the number of idle channels after the l-th round of decision, where f is a constant factor whose specific value depends on the device performance and is typically taken as 15±3. P′ j The average power of the channels that were determined to be idle channels, and the initial number of idle channels. Sort by smallest to largest and then select the first... The initial threshold is calculated using the average power of each channel. After calculating the decision threshold, the occupancy status of each channel is determined using the following decision criteria:

[0062]

[0063] This represents the decision result of the i-th channel after the l-th round of decisions, where 1 indicates idle and 0 indicates occupied. Statistics are compiled after the end of this round of decisions. number of channels like The threshold for this round will be calculated based on the judgment result. And proceed to the next round of judgment; if The loop ends then, and the result of this round's judgment becomes the final judgment.

[0064] Step 1.3: After obtaining the decision result, the number of idle channels is calculated. Then, the occupancy rate of the current frequency band is estimated using the following formula:

[0065]

[0066] Step 2: Calculate the optimal number of frequency entry points. Establish a mathematical model based on the relationship between average terminal pairing time, channel occupancy rate, and the number of frequency entry points. Analyze the mathematical model to find the number of frequency entry points that minimizes the average terminal pairing time under a given channel occupancy rate.

[0067] Let P be the probability that channel k is occupied. ko The probability of each channel being occupied is independent and identically distributed, as follows:

[0068] P 1o =P 2o =...=P No =P o ,

[0069] The number of channels selected by the cognitive wireless communication terminal is n, where n∈[1,N]. When all channels selected during the terminal pairing process are occupied, the terminal waits for T. w =nT0 time, continue searching for an available channel among the selected channels, where T0 is the shortest time required for the terminal device to exchange control information. The probability that the cognitive wireless communication terminal can find an available channel is:

[0070]

[0071] The probability that the terminal finds a usable channel only on the Lth attempt is:

[0072] P L =P fail L-1 ×P succ =P o n(L-1) ×(1-P o n ),

[0073] When a usable channel is found only on the Lth attempt, the time required for terminal pairing is:

[0074] T L = (L-1)T w +T M ,

[0075] Among them, T M To determine the maximum time required for terminal pairing under the condition that at least one channel is available, the average terminal pairing time when a cognitive wireless communication terminal selects n channels for terminal pairing is:

[0076]

[0077] Where the expectation of L is:

[0078]

[0079] have:

[0080]

[0081] The pairing times corresponding to different frequencies and the number of inputs are:

[0082]

[0083] Let T M =n,T w =max(T) M ) = N, T E (n, P) o )for:

[0084]

[0085] The current channel occupancy rate P of the operating frequency band is obtained through spectrum sensing and decision-making. o ;

[0086] Calculate the average terminal pairing time corresponding to the number of frequency inlets, select the number of frequency inlets that minimizes the average terminal pairing time as the optimal number of frequency inlets, and select the number of inlets that minimizes the pairing time as the optimal number of frequency inlets n0.

[0087]

[0088] Step 3: Select the frequency entry set. Each terminal maps all channels to N tags according to the center frequency from smallest to largest. Based on the optimal number of frequency entry points n0 obtained in Step 2, select the channels corresponding to the first n0 tags from the N tags in sequence as the frequency entry set for this terminal pairing. Finally, terminal pairing is performed based on these frequency entry points.

[0089] In step 1 of the above embodiments, the channel occupancy of the current operating frequency band can be estimated in real time using the combined sensing and decision information. Alternatively, the channel occupancy can be estimated using a combination of historical information and current sensing and decision information. Or, the channel occupancy can be estimated using only the current local spectrum sensing and decision information. Here, channel estimation using the current local spectrum sensing and decision information means that after sensing information within the operating frequency band, the terminal device independently determines the current channel occupancy and estimates the occupancy of the entire operating frequency band based on the channel occupancy obtained after this determination. This estimation method has the advantages of simple implementation and strong applicability.

[0090] In step 2 of the above embodiment, there are various mathematical models relating the average terminal pairing time, channel occupancy, and number of frequency inlets. The terminal waiting time T varies depending on the pairing method. w and maximum pairing time T M Different models have different parameters, and the corresponding mathematical models also differ. For example, some common models have parameters T. M =O(N), T w =NT0,T M =O(N) 2 ), T w =N 2 T0, T M =O(N) 3 ), T w =N 3 T0, etc., for T M =O(N), T w =NT0 indicates that the longest terminal pairing time and the number of channels N are linear functions, and the corresponding waiting time is also proportional to the number of channels N with a coefficient of T0.

[0091] In step 3 of the above embodiment, the frequency entry point is selected sequentially from the total set, or in reverse order from the total set, or starting from a specified channel.

[0092] With a total of 100 channels, compared to other schemes such as EJS (Enhanced Jump-Stay), ECGB (Enhanced Channel-Grouping Based algorithm), ACH (Asymmetric Frequency Hopping Sequence Pairing Scheme), and SJRW (Sender Frequency Hopping Receiver Waiting Pairing Scheme), the pairing time achieved by the method described in this embodiment is significantly lower than other schemes. Figure 3 As shown, in the best case, the pairing time of these schemes can be reduced to 1%, while in general, the pairing time is 10% of that of other schemes.

[0093] This invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims.

Claims

1. A cognitive wireless communication terminal pairing method based on frequency entry, characterized in that, include: Step 1: Calculate the current channel occupancy rate. Utilize the terminal's own sensing and decision-making capabilities to obtain the channel occupancy status of the current frequency band, and then calculate the overall occupancy status of the working frequency band based on the current channel occupancy status. Step 2: Calculate the optimal number of frequency inlets. Establish a mathematical model based on the relationship between average terminal pairing time, channel occupancy, and the number of frequency inlets. Analyze the mathematical model to find the number of frequency inlets that minimizes the average terminal pairing time for a given channel occupancy rate. Set channel The probability of it being occupied is The probability of each channel being occupied is independent and identically distributed, as follows: ……（5）， The number of channels selected by the cognitive wireless communication terminal is When all channels selected during the terminal pairing process are occupied, the terminal waits. After a certain time, continue searching for available channels among the selected channels, where, The shortest time required for terminal devices to exchange control information, and the probability that a cognitive wireless communication terminal can find an available channel, are: ……（6）， in, , After substituting into equation (5), Terminal No. The probability of finding a usable channel on the second attempt is: ……（7）， in, To be The result after substitution, the first When an available channel is found for the second time, the time required for terminal pairing is: ……（8）， in, In the selection of cognitive wireless communication terminals The average terminal pairing time when pairing terminals on each channel is: ……（9）， in, The expectation is: ……（10）， According to equations (7) and (8), we have: ……（11）， According to equations (8) and (9), we have: ……（12）， set up , , for: ……（13）， Obtain the current channel occupancy rate of the operating frequency band through spectrum sensing and decision-making. ; Calculate the average terminal pairing time corresponding to the number of frequency inlets according to formula (11), and select the number of frequency inlets that minimizes the average terminal pairing time as the optimal number of frequency inlets. Step 3: Select the frequency entry set. Based on the optimal number of frequency entry points, the main terminal device selects a corresponding number of frequencies from the available channel set as the frequency entry set for subsequent terminal pairing; and selects a corresponding number of frequencies from the total channel set of the terminal device as the frequency entry set for subsequent terminal pairing.

2. The cognitive wireless communication terminal pairing method based on frequency entry as described in claim 1, characterized in that, In step 1: Divide the frequency bands in which cognitive wireless communication terminals operate into Non-overlapping channels, of which, The average power of each channel is obtained after spectrum sensing. and peak power ,right After sorting the average power of each channel from smallest to largest, select the top... The decision threshold is calculated using a set of values, with the initial threshold denoted as . ,in: ……（1）， ……（2）， in, Indicates the sorted order of the first... Average power value, It is a constant factor, based on the decision threshold. Each channel is used for decision-making, and the decision-making criteria are as follows: ……（3）， in, Indicates the first Channel 1 In the round-robin decision, the channel status is 1, indicating that the channel is idle and available, and 0, indicating that the channel is occupied and unavailable. For the first Peak power of each channel It is the first The decision threshold calculated in the first round, the first round Statistics after the round of judgments Number of channels ,like ,according to Calculate the new threshold for channel average power And proceed to the next round of judgment; if The verdict concluded, and the final outcome was... One idle channel and One occupied channel; Therefore, the current channel occupancy rate of the operating frequency band can be calculated as follows: ……（4）。 3. The cognitive wireless communication terminal pairing method based on frequency entry as described in claim 1, characterized in that, In step 3: Each cognitive wireless communication terminal maps each channel to On each label, each cognitive wireless communication terminal is selected from the estimated optimal number of frequency entry points. Channels are selected sequentially from the tags as the frequency entry points for this terminal pairing.

4. The cognitive wireless communication terminal pairing method based on frequency entry as described in claim 1, characterized in that, In step 1, the channel occupancy of the current operating frequency band is estimated in real time using the combined sensing and decision information.

5. The cognitive wireless communication terminal pairing method based on frequency entry according to claim 1, characterized in that, In step 3, the frequency inputs are selected sequentially from the total set.

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