CN106412928A - Collaborative cognitive radio network cross-layer design method - Google Patents

Abstract

The present invention relates to a cross-layer design method of a cooperative cognitive wireless network, which is used in a cooperative cognitive wireless network. The user network includes a primary user base station and multiple primary users, and the primary user base station communicates with each primary user. The secondary user network includes a secondary user base station and multiple secondary users, and the secondary user base station communicates with each secondary user. When the primary user does not occupy its licensed frequency band for communication, the cross-layer design method of cooperative cognitive wireless network can timely notify the secondary user who needs to use the frequency band information of the idle frequency band, so as not to interfere with the normal communication of the primary user. , to ensure that the secondary users communicate in a timely and rapid manner.

Description

Cross-layer Design Method for Cognitive Cognitive Wireless Network

technical field

The present invention relates to the communication field, in particular to a cross-layer design method for a collaborative cognitive wireless network.

Background technique

Cognitive Radio technology (CR for short) is a kind of cognitive detection that can "opportunistically" detect the idle spectrum, so as to share and utilize the detected idle spectrum, and then solve the problem of shortage of spectrum resources, so as to truly realize the improvement of spectrum resources. Utilization of Emerging Communication Technologies.

The cognitive process of cognitive radio is as follows: First, the secondary user (or cognitive user) continuously monitors the licensed frequency band resources in the surrounding environment by using spectrum sensing; Under the condition that the performance is almost unaffected, the secondary user adaptively adjusts the transceiver equipment, and adjusts the transceiver equipment to the idle frequency band for communication; finally, when the secondary user detects that the primary user signal appears, the secondary user quickly releases the currently used The frequency band is used by the primary user to which the frequency band belongs, so as to prevent the primary user from being interfered when using the frequency band for communication.

The cognitive wireless network is based on the cognitive radio technology, and is formed by at least primary users and secondary users, so that the secondary users opportunistically utilize the idle frequency band of the primary user. However, in the cognitive wireless network formed by the primary user and the secondary user, once the primary user does not occupy its licensed frequency band for communication, the licensed frequency band is in an idle state at this time. How to timely notify the secondary user of the idle frequency band information authorized to the primary user when the secondary user needs to use the frequency band to communicate, so as to meet the communication requirements of the secondary user and not affect the normal communication of the primary user to become a cognitive wireless network real problems faced.

Contents of the invention

The technical problem to be solved by the present invention is to provide a cooperative cognitive wireless system that can timely notify the idle frequency band information to the secondary user who needs to use the frequency band when the primary user does not occupy its authorized frequency band for communication. Network cross-layer design method.

The technical solution adopted by the present invention to solve the problems of the technologies described above is:

A cross-layer design method for a collaborative cognitive wireless network, used in a collaborative cognitive wireless network, characterized in that the collaborative cognitive wireless network consists of at least one primary user network, a fusion center, and at least one secondary user network, and the primary user network Including a primary user base station and multiple primary users, the primary user base station communicates with each primary user, and the secondary user network includes a secondary user base station and multiple secondary users, and the secondary user base station communicates with each secondary user; the cooperative cognition The wireless network cross-layer design method includes the following steps 1 to 8:

Step 1, establish communication connections between the primary user base stations in each primary user network and the secondary user base stations in each secondary user network, so that the primary user base station can receive the secondary user information sent by the secondary user base station in the secondary user network at any time The access service requirements for using the frequency band of the primary user network for communication;

Step 2, the primary user base stations in each primary user network and the secondary user base stations in each secondary user network respectively obtain their own positions correspondingly, and establish a fusion center with the primary user base stations in each primary user network and the secondary user base stations in each secondary user network. The communication connection between the secondary user base stations, so that the fusion center can obtain the location information sent by each primary user base station and each secondary user base station;

Step 3, the fusion center calculates the straight-line distance values between each primary user base station and each secondary user base station according to the position information sent by each primary user base station and each secondary user base station, and calculates the distance between each primary user base station and each secondary user base station according to the obtained The distance value between user base stations classifies and manages the coordinated access between the primary user network and the secondary user network:

For a primary user base station, when there is a minimum distance between the secondary user base station and the primary user base station, the secondary user base station and the primary user base station are selected as paired base stations for cross-layer access, and the primary user base station The base station is responsible for the access service of the secondary user in the secondary user network where the secondary user base station is located; otherwise, continue to search for the secondary user base station with the minimum distance value from the primary user base station as the paired base station for cross-layer access with the primary user base station , so that the primary user base station is exclusively responsible for the access service of the secondary user in the secondary user network where the paired secondary user base station is located;

Step 4, in each sub-user network, the sub-user base station presets M alliance partition thresholds, and each sub-user sends the acquired SNR to the sub-user base station in the same sub-user network, and the sub-user The base station performs alliance partitioning on the secondary users in the secondary user network and assigns the alliance number of each partition; M≥1; the process of the secondary user base station's alliance partitioning of the secondary users in the secondary user network includes the following steps 4-1 to Step 4-4:

Step 4-1, the base station of the secondary user sequentially calculates the normalized interference factor of the interference from other secondary users in the network suffered by each user according to the signal-to-noise ratio sent by each user in the secondary user network; wherein, the secondary user CR The normalized interference factor of _i is denoted as

SNR _i represents the signal-to-noise ratio of the secondary user CR _i , and N represents the total number of all secondary users in the secondary user network where the secondary user CR _i is located; i=1,2,...,N, N≥3;

Step 4-2, the secondary user base station calculates the normalized trust index of each user in all secondary user networks; where: the normalized trust index of the secondary user CR _i is denoted as

Step 4-3, the secondary user base station obtains the priority access index for each user to access the primary user network according to the obtained normalized interference factor and normalized trust index of each user; wherein, the secondary user CR _i accesses the primary user network The priority access index of the user network is denoted as ρ _i ; is the normalized trust index of secondary user CR _i , is the normalized interference factor of the secondary user CR _i ;

Step 4-4, the secondary user base station presets M alliance partition thresholds, and sets M+1 alliance partition segments as [-∞,λ ₁ ), [λ ₁ ,λ ₂ ),...,[λ _M-1 ,λ _M ) and [λ _M ,∞); wherein, the priority access index corresponding to the secondary user in the first alliance is in the [-∞,λ ₁ ) interval, and the priority access index corresponding to the secondary user in the second alliance The priority access index is in the [λ ₁ , λ ₂ ) interval, and so on. The priority access index corresponding to the secondary user in the Mth alliance is in the [λ _M-1 , λ _M The priority access index corresponding to the secondary users in the +1 alliance is in the [λ _M ,∞) interval segment, and each alliance is numbered in turn;

Step 5, after each primary user base station searches for its dedicated secondary user network, when the secondary user in the secondary user network needs to use the frequency band for communication, the secondary user sends its alliance number to the secondary user base station, and the The secondary user base station sends a frequency band request to the corresponding paired primary user base station, so that the primary user base station can monitor the occupancy status of the authorized frequency bands used by each primary user in the primary user network, and send the monitored idle spectrum information to For the secondary user base station paired with the primary user base station:

The primary user base station monitors the authorized frequency bands occupied by each primary user in the primary user network on the physical layer in real time to integrate the idle spectrum in the primary user network and identify the modulation of the primary user signal corresponding to each licensed frequency band mode, and the master user base station updates the idle spectrum it monitors in real time, and after uploading the latest idle spectrum of the master user base station to the MAC layer management, the master user base station will monitor the newly updated idle spectrum The information and the modulation mode of each primary user signal are forwarded to the secondary user base station paired with the primary user base station;

Step 6: In the secondary user network where the secondary user that needs to use the frequency band to communicate is located, after the secondary user base station in the secondary user network receives the idle frequency spectrum and the primary user signal modulation method sent by the primary user base station, the secondary user base station The user base station generates multiple discontinuous idle frequency bands using OFDMA technology in the idle spectrum, and generates multiple frequency hopping patterns based on the generated idle frequency bands using frequency hopping technology, and according to the alliance number of the secondary user, the The secondary user base station dynamically assigns all the received primary user signal modulation methods and the generated frequency hopping patterns to the secondary users who need to use the frequency band for communication, and then the secondary users adjust their own signal modulation methods according to the received primary user signal modulation methods. Based on the modulation method of the primary user signal, the secondary user occupies different frequency bands for communication at different times according to the frequency hopping pattern, so as to meet the requirements of the secondary user to access the primary user network, so as to realize the non-interference access of the secondary user to the primary user network, so that the secondary user can use the free frequency band in the primary user network to communicate;

Step 7, after the secondary user in step 6 completes the communication by using the frequency band, the secondary user sends the notification information of vacating the frequency band and the alliance number to the secondary user base station in the secondary user network, so that the secondary user base station Send the feedback information that the secondary user has vacated the frequency band to the corresponding primary user base station;

Step 8: After the primary user base station receives the feedback information about the frequency band vacated by the secondary user base station, if the primary user base station judges that the primary user to which the frequency band belongs has not requested to occupy this frequency band, the primary user base station will use the frequency band as a cross-band The standby frequency band accessed by the upper layer is used for subsequent access by secondary users who need frequency band communication; if the primary user base station judges that the primary user to which the frequency band belongs makes a request to occupy the frequency band, the primary user base station will feedback that the frequency band can be resumed. The information is sent to the main user to realize the normal use of the frequency band by the main user.

Compared with the prior art, the present invention has the advantages of:

First of all, the cross-layer design method for cooperative cognitive wireless network provided by the present invention divides the cognitive wireless network into a primary user network and a secondary user network, so as to separate the primary user that provides idle frequency bands and the secondary users that need idle frequency band communication, accurately Clearly define the secondary users who need to cross layers to realize the access service;

Secondly, in each primary user network, a primary user base station is specially responsible for monitoring the idle frequency band in the network; in each secondary user network, a secondary user base station is specially responsible for communicating with the paired primary user base station, so as to realize the The secondary users who need to communicate in the network successfully use the free frequency band in the primary user network;

Again, after the secondary user base station receives the idle frequency spectrum sent by the paired primary user base station, the secondary user base station is responsible for dividing the idle frequency spectrum into multiple unused idle frequency bands to meet the secondary user communication needs in the network where the secondary user base station is located. , which can well adapt to the secondary user communication needs in the secondary user network, and ensures the monitoring efficiency of the primary user base station to the idle spectrum in the primary user network;

Finally, after the secondary user vacates the frequency band, after the secondary user base station in the same network sends the vacated frequency band information to the paired primary user base station, the primary user base station can choose whether to vacate the frequency band according to the needs of the primary user As a spare frequency band for cross-layer access, it is used for the access of secondary users who need frequency band communication, so that when the secondary user needs frequency band communication, the spare frequency band can be provided to the secondary user through the secondary user base station at the first time, ensuring Secondary users communicate in a timely and rapid manner.

Description of drawings

FIG. 1 is a schematic diagram of a cooperative cognitive wireless network in an embodiment of the present invention;

FIG. 2 is a schematic flowchart of a method for cross-layer design of a collaborative cognitive wireless network in an embodiment of the present invention;

FIG. 3 is a schematic diagram of a frequency hopping pattern in an embodiment of the present invention.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

The collaborative cognitive wireless network cross-layer design method in this embodiment is used in a collaborative cognitive wireless network. The collaborative cognitive wireless network consists of at least one primary user network, a fusion center, and at least one secondary user network. The primary user network It includes a primary user base station and multiple primary users, and the primary user base station communicates with each primary user. The secondary user network includes a secondary user base station and multiple secondary users, and the secondary user base station communicates with each secondary user; The cooperative cognitive network structure in the embodiment is shown in FIG. 1. It is set in the cooperative cognitive wireless network, the number of primary user networks is marked as X, the number of primary user networks is marked as PUN _x , and the number of primary user networks in PUN _x is The number of primary users in the primary user network PUN x is marked as I, the primary user in the primary user network PUN _x is marked as PU _x,i , the primary user base station in the primary user network PUN _x is marked as PUBS _x ; the fusion center is marked as FC; the secondary user network The number is marked as Y, the secondary user network is marked as CRN _y , the number of secondary users in the secondary user network CRN _y is J, the secondary users in the secondary user network CRN _y are marked as CR _y,j , and the number of secondary users in the secondary user network CRN _y is CR y,j . The secondary user base station is marked as CRBS _y ; X≥1, 1≤x≤X, Y≥1, 1≤y≤Y, 1≤j≤J; the number of primary users in the primary user network PUN ₁ is set to I ₁ , the number of primary users in the primary user network PUN ₂ is I ₂ , ..., the number of primary users in the primary user network PUN _X is I _X ; the number of secondary users in the secondary user network CRN ₁ is J ₁ , the secondary The number of secondary users in the user network CRN ₂ is J ₂ , ..., and the number of secondary users in the secondary user network CRN _Y is J _Y ; as shown in Figure 2, the method for cross-layer design of the cooperative cognitive wireless network includes the following steps :

Step 1, establish communication connections between the primary user base stations in each primary user network and the secondary user base stations in each secondary user network, so that the primary user base station can receive the secondary user information sent by the secondary user base station in the secondary user network at any time The access service requirements for using the frequency band of the primary user network for communication;

For example, in the cooperative cognitive wireless network shown in FIG. 1 , the primary user base station PUBS ₁ of the primary user network PUN ₁ is connected with the secondary user base station CRBS ₁ , secondary user base station CRBS ₂ , ..., secondary user base station CRBS _y-1 and The secondary user base station CRBS _y establishes a communication connection; the primary user base station PUBS ₂ respectively establishes communication connections with the secondary user base station CRBS ₁ , the secondary user base station CRBS ₂ , ..., the secondary user base station CRBS _Y-1 , and the secondary user base station CRBS _Y ; and so on , the primary user base station PUBS ₃ to the primary user base station PUBS ₁ respectively establish communication connections with the secondary user base station CRBS ₁ , the secondary user base station CRBS ₂ , ..., the secondary user base station CRBS _y-1 , and the secondary user base station CRBS _y ;

Among them, the primary user base station PUBS ₁ to the primary user base station CRBS _y are ready to receive the access service request sent by the secondary user through the secondary user base station at any time;

Step 2, the primary user base stations in each primary user network and the secondary user base stations in each secondary user network respectively obtain their own positions correspondingly, and establish a fusion center with the primary user base stations in each primary user network and the secondary user base stations in each secondary user network. The communication connection between the secondary user base stations, so that the fusion center can obtain the location information sent by each primary user base station and each secondary user base station;

In the primary user network PUN _x , the primary user base station PUBS _x obtains its own position as 1≤x≤X; in the secondary user network CRN _y , the self-position obtained by the secondary user base station CRBS _y is 1≤y≤Y;

Step 3, the fusion center calculates the straight-line distance values between each primary user base station and each secondary user base station according to the position information sent by each primary user base station and each secondary user base station, and calculates the distance between each primary user base station and each secondary user base station according to the obtained The distance value between user base stations classifies and manages the coordinated access between the primary user network and the secondary user network:

For a primary user base station, when there is a minimum distance between the secondary user base station and the primary user base station, the secondary user base station and the primary user base station are selected as paired base stations for cross-layer access, and the primary user base station The base station is responsible for the access service of the secondary user in the secondary user network where the secondary user base station is located; otherwise, continue to search for the secondary user base station with the minimum distance value from the primary user base station as the paired base station for cross-layer access with the primary user base station , so that the primary user base station is exclusively responsible for the access service of the secondary user in the secondary user network where the paired secondary user base station is located;

The fusion center FC according to the own position of each primary user base station PUBS _x and the own position of each user base station CRBS _y The linear distance between the primary user base station PUBS _x and the secondary user base station CRBS _y is obtained as d(PUBS _x , CRBS _y ):

Among them, 1≤x≤X, 1≤y≤Y;

For example, in the primary user network PUN ₁ , for the primary user base station PUBS ₁ , the straight-line distance values between each secondary user base station and the primary user base station PUBS _x are d(PUBS ₁ , CRBS ₁ ), d(PUBS ₁ , CRBS ₂ ),..., d(PUBS ₁ , CRBS _Y ); if d(PUBS ₁ , CRBS ₂ ) is the minimum value among the Y linear distance values, then the secondary user base station CRBS ₂ and the primary user base station PUBS ₁ are used as the cross layer access paired base station, the primary user base station PUBS ₁ is responsible for the access service of the secondary user in the secondary user network CRN ₂ where the paired secondary user base station CRBS ₂ is located; of course, if d(PUBS ₁ , CRBS _Y ) is The minimum value of the Y straight-line distance values, the secondary user base station CRBS _Y and the primary user base station PUBS ₁ are used as paired base stations for cross-layer access, and the primary user base station PUBS ₁ is specifically responsible for the paired secondary user base station CRBS _Y The access service of the secondary user in the secondary user network CRN _Y where it is located;

Similarly, in other primary user networks, the secondary user base stations that are paired with the corresponding primary user base stations are sequentially obtained, and the process of obtaining the paired base stations will not be repeated here;

Step 4, in each sub-user network, the sub-user base station presets M alliance partition thresholds, and each sub-user sends the acquired SNR to the sub-user base station in the same sub-user network, and the sub-user The base station performs alliance partitioning on the secondary users in the secondary user network and assigns the alliance number of each partition; M≥1; the process of the secondary user base station's alliance partitioning of the secondary users in the secondary user network includes the following steps 4-1 to Step 4-4:

Step 4-1, the base station of the secondary user sequentially calculates the normalized interference factor of the interference from other secondary users in the network suffered by each user according to the signal-to-noise ratio sent by each user in the secondary user network; wherein, the secondary user CR The normalized interference factor of _i is denoted as

SNR _i represents the signal-to-noise ratio of the secondary user CR _i itself, and N represents the total number of all secondary users in the secondary user network where the secondary user CR _i is located; i=1,2,...,N, N≥3; in addition, according to each The signal-to-noise ratio of the secondary user is calculated to obtain the normalized interference index of the surrounding secondary users to the secondary users in the secondary user network, so as to truly reflect the comprehensive interference situation of the surrounding secondary users through the normalized interference index;

Step 4-2, the secondary user base station calculates the normalized trust index of each user in all secondary user networks; where: the normalized trust index of the secondary user CR _i is denoted as

Step 4-3, the secondary user base station obtains the priority access index for each user to access the primary user network according to the obtained normalized interference factor and normalized trust index of each user; wherein, the secondary user CR _i accesses the primary user network The priority access index of the user network is denoted as ρ _i ; is the normalized trust index of secondary user CR _i , is the normalized interference factor of the secondary user CR _i ; the priority access index of the secondary user indicates the order in which the secondary user enjoys the available frequency band when there is a frequency band available; among them, the secondary user base station prioritizes priority access Secondary users with a high index use the available frequency band to access the network;

Step 4-4, the secondary user base station presets M alliance partition thresholds, and sets M+1 alliance partition segments as [-∞,λ ₁ ), [λ ₁ ,λ ₂ ),...,[λ _M-1 ,λ _M ) and [λ _M ,∞); wherein, the priority access index corresponding to the secondary user in the first alliance is in the [-∞,λ ₁ ) interval, and the priority access index corresponding to the secondary user in the second alliance The priority access index is in the [λ ₁ , λ ₂ ) interval, and so on. The priority access index corresponding to the secondary user in the Mth alliance is in the [λ _M-1 , λ _M The priority access index corresponding to the secondary users in the +1 alliance is in the [λ _M ,∞) interval segment, and each alliance is numbered in turn;

For example, for the secondary user network CRN _y , the number of secondary users in the secondary user network CRN _y is J, and the secondary user base station CRBS _y presets five alliance partition thresholds as λ ₁ , λ ₂ , λ ₃ , λ ₄ , λ ₅ ; λ ₁ =0.1, λ ₂ =0.2, λ ₃ =0.4, λ ₄ =0.5 and λ ₅ =0.7;

The priority access index of secondary users in the first alliance C ₁ is in the interval of (-∞,0.1], and the priority access index of secondary users in the second alliance C ₂ is in the interval of (0.1,0.2] , the priority access index of secondary users in the third alliance C ₃ is in the interval of (0.2,0.4], and the priority access index of secondary users in the fourth alliance C ₄ is in the interval of (0.4,0.5] , the priority access index of secondary users in the fifth alliance C ₅ is in the interval of (0.5,0.7], and the priority access index of secondary users in the sixth alliance C ₆ is in the interval of (0.7,∞) ;

Thus, when the priority access index of the secondary user CR _y,1 in the secondary user network CRN _y is in the range of (0.2,0.4], the confederation number of the secondary user CR ₁ is marked as C ₃ ; similarly, it can Obtain the alliance number of other sub-users;

Step 5, after each primary user base station searches for its dedicated secondary user network, when the secondary user in the secondary user network needs to use the frequency band for communication, the secondary user sends its alliance number to the secondary user base station, and the The secondary user base station sends a frequency band request to the corresponding paired primary user base station, so that the primary user base station can monitor the occupancy status of the authorized frequency bands used by each primary user in the primary user network, and send the monitored idle spectrum information to For the secondary user base station paired with the primary user base station:

The primary user base station monitors the authorized frequency bands occupied by each primary user in the primary user network on the physical layer in real time to integrate the idle spectrum in the primary user network and identify the modulation of the primary user signal corresponding to each licensed frequency band mode, and the master user base station updates the idle spectrum it monitors in real time, and after uploading the latest idle spectrum of the master user base station to the MAC layer management, the master user base station will monitor the newly updated idle spectrum The information and the modulation mode of each primary user signal are forwarded to the secondary user base station paired with the primary user base station;

For example, after the primary user base station PUBS ₁ searches for its dedicated secondary user network CRN _Y , when the secondary user CRY _,j in the secondary user network CRN _Y needs to use the frequency band for communication, the secondary user CRY _,j sends Its alliance number is given to the secondary user base station CRBS _Y , and the secondary user base station CRBS _Y sends a frequency band request to the corresponding paired primary user base station PUBS ₁ , and the primary user base station PUBS ₁ monitors the primary user network PUN ₁ where it is located The occupancy status of the licensed frequency bands used by each primary user in the country:

The primary user base station PUBS ₁ monitors the licensed frequency bands occupied by each primary user in the primary user network PUN ₁ on the physical layer in real time to integrate the idle spectrum in the primary user network PUN ₁ and identify the licensed frequency bands of each licensed frequency band. Corresponding to the modulation mode of the primary user signal, and the idle spectrum monitored by the primary user base station PUBS ₁ is updated in real time, and after uploading the idle spectrum recently updated by the primary user base station PUBS ₁ to the MAC layer management, the primary user base station PUBS ₁ forwards the recently updated idle spectrum information and the modulation mode of each primary user signal to the secondary user base station CRBS _Y paired with the primary user base station PUBS ₁ ; where it is assumed that the primary user base station PUBS ₁ forwards to the secondary user base station The frequency band of CRBS _Y is authorized for use by the main user PU _{1, 2} ; here, the idle frequency spectrum obtained by the integration of the main user base station PUBS ₁ includes at least one available idle frequency band;

Step 6: In the secondary user network where the secondary user that needs to use the frequency band to communicate is located, after the secondary user base station in the secondary user network receives the idle frequency spectrum and the primary user signal modulation method sent by the primary user base station, the secondary user base station The user base station generates multiple discontinuous idle frequency bands using OFDMA technology in the idle spectrum, and generates multiple frequency hopping patterns based on the generated idle frequency bands using frequency hopping technology, and according to the alliance number of the secondary user, the The secondary user base station dynamically assigns all the received primary user signal modulation methods and the generated frequency hopping patterns to the secondary users who need to use the frequency band for communication, and then the secondary users adjust their own signal modulation methods according to the received primary user signal modulation methods. Based on the primary user signal modulation method, so that the secondary user does not interfere with the signal in the primary user network, and the secondary user occupies different frequency bands for communication at different times according to the frequency hopping pattern, so that the secondary user can access to the primary user network. The requirements in the user network, so that the secondary user can access the primary user network without interference, so that the secondary user can use the idle frequency band in the primary user network to communicate;

Corresponding to step 5, assuming that the consortium number of the secondary user CRY _,j is C ₅ , in the secondary user network CRN _Y where the secondary user CRY _,j needs to use frequency band communication, the secondary user network CRN After the secondary user base station CRBS _Y in _Y receives the idle frequency spectrum sent by the primary user base station PUBS ₁ , the secondary user base station CRBS _Y uses frequency hopping technology to generate a frequency hopping pattern according to the idle frequency spectrum, and according to the secondary user base station CRBS _Y,j The consortium number C ₅ , to dynamically assign the generated frequency hopping pattern to the secondary user C R _Y,j who needs to use the frequency band for communication, and then the secondary user C R _Y,j according to the received frequency hopping pattern at different times Occupy different frequency bands for communication to meet the requirements of the secondary user CR _Y,j to access the primary user network PUN ₁ , so as to realize the secondary user CR _Y,j access to the primary user network PUN ₁ to meet the requirements of the secondary user CR _{Y, j} use the free frequency band in the primary user network PUN ₁ to communicate; wherein, after the primary user base station sends the idle spectrum information in the network to the paired secondary user base station, the secondary user base station is responsible for generating the idle spectrum Multiple discontinuous idle frequency bands can fully meet the actual needs of multiple secondary users in the secondary user network using frequency bands for communication; if the primary user base station is responsible for generating multiple discontinuous idle frequency bands from the idle frequency band, it will To a certain extent, the monitoring efficiency of the primary user base station on the frequency band occupancy of the primary user network is weakened, and because the primary user base station cannot immediately know the number of secondary users who need to use the frequency band for communication, it will also cause the idle frequency band generated by the primary user base station The number does not match the number of secondary users actually needed;

In this embodiment, the secondary user base station is specially responsible for generating the required number of idle frequency bands according to the actual needs of the secondary user, which can well adapt to the secondary user communication needs in the secondary user network, and ensures that the primary user base station The monitoring efficiency of the idle frequency spectrum in the primary user network; the frequency hopping pattern generated by the secondary user base station CRBS _Y using frequency hopping technology according to the idle frequency band is shown in Figure 3; in the frequency hopping pattern shown in Figure 3, the secondary user base station will pair The idle frequency spectrum sent by the primary user base station is divided into h discontinuous frequency bands for use by secondary users who need to communicate;

Step 7, after the secondary user in step 6 completes the communication by using the frequency band, the secondary user sends the notification information of vacating the frequency band and the alliance number to the secondary user base station in the secondary user network, so that the secondary user base station Send the feedback information that the secondary user has vacated the frequency band to the corresponding primary user base station;

After the secondary user CR _Y,j completes the communication by using the frequency band, the secondary user CR _Y,j sends the notification information of vacating the frequency band and the alliance number C ₅ to the secondary user base station CRBS _Y in the secondary user network CRN _Y to The feedback information that the secondary user has vacated the frequency band is sent to the corresponding primary user base station PUBS ₁ by the secondary user base station CRBS _Y ;

Step 8: After the primary user base station receives the feedback information about the frequency band vacated by the secondary user base station, if the primary user base station judges that the primary user to which the frequency band belongs has not requested to occupy this frequency band, the primary user base station will use the frequency band as a cross-band The standby frequency band accessed by the upper layer is used for the access of secondary users who need frequency band communication; if the primary user base station judges that the primary user to which the frequency band belongs makes a request to occupy the frequency band, the primary user base station will feed back the information that the frequency band can resume occupation To the main user, in order to realize the normal use of the frequency band by the main user.

Correspondingly, after the primary user base station PUBS ₁ receives the feedback information about the vacated frequency band from the secondary user base station CRBS _Y , if the primary user base station PUBS ₁ judges that the primary user PU _{1 and 2} to which the frequency band belongs have not requested to occupy the frequency band , then the primary user base station _{PUBS 1} uses this frequency band as a spare frequency band for cross-layer access for secondary user access that requires frequency band communication _; When the frequency band is requested, the primary user base station PUBS ₁ feeds back the information that the frequency band can be resumed to the primary user PU _1,2 , so as to realize the normal use of the frequency band by the primary user PU _1,2 .

Claims (1)

1. A cross-layer design method for a collaborative cognitive wireless network, used in a collaborative cognitive wireless network, characterized in that the collaborative cognitive wireless network consists of at least one primary user network, a fusion center, and at least one secondary user network, and the primary user The network includes a primary user base station and multiple primary users, and the primary user base station communicates with each primary user, and the secondary user network includes a secondary user base station and multiple secondary users, and the secondary user base station communicates with each secondary user; the collaborative The cognitive wireless network cross-layer design method includes the following steps 1 to 8: Step 1, establish communication connections between the primary user base stations in each primary user network and the secondary user base stations in each secondary user network, so that the primary user base station can receive the secondary user information sent by the secondary user base station in the secondary user network at any time The access service requirements for using the frequency band of the primary user network for communication; Step 2, the primary user base stations in each primary user network and the secondary user base stations in each secondary user network respectively obtain their own positions correspondingly, and establish a fusion center with the primary user base stations in each primary user network and the secondary user base stations in each secondary user network. The communication connection between the secondary user base stations, so that the fusion center can obtain the location information sent by each primary user base station and each secondary user base station; Step 3, the fusion center calculates the straight-line distance values between each primary user base station and each secondary user base station according to the position information sent by each primary user base station and each secondary user base station, and calculates the distance between each primary user base station and each secondary user base station according to the obtained The distance value between user base stations classifies and manages the coordinated access between the primary user network and the secondary user network: For a primary user base station, when there is a minimum distance between the secondary user base station and the primary user base station, the secondary user base station and the primary user base station are selected as paired base stations for cross-layer access, and the primary user base station The base station is responsible for the access service of the secondary user in the secondary user network where the secondary user base station is located; otherwise, continue to search for the secondary user base station with the minimum distance value from the primary user base station as the paired base station for cross-layer access with the primary user base station , so that the primary user base station is exclusively responsible for the access service of the secondary user in the secondary user network where the paired secondary user base station is located; Step 4, in each sub-user network, the sub-user base station presets M alliance partition thresholds, and each sub-user sends the acquired SNR to the sub-user base station in the same sub-user network, and the sub-user The base station performs alliance partitioning on the secondary users in the secondary user network and assigns the alliance number of each partition; M≥1; the process of the secondary user base station's alliance partitioning of the secondary users in the secondary user network includes the following steps 4-1 to Step 4-4: Step 4-1, the base station of the secondary user sequentially calculates the normalized interference factor of the interference from other secondary users in the network suffered by each user according to the signal-to-noise ratio sent by each user in the secondary user network; wherein, the secondary user CR The normalized interference factor of _i is denoted as ${\mathrm{<span\; class="notranslate">\; \&zeta;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; i</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}\frac{{{\mathrm{<span\; class="notranslate">\; SNR</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}_{\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; SNR</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{{{\mathrm{<span\; class="notranslate">\; SNR</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}}{\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>{{\mathrm{<span\; class="notranslate">\; SNR</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; ;</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{{\mathrm{<span\; class="notranslate">\; \&zeta;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; \&zeta;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; \&zeta;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; ;</span>$ SNR _i represents the signal-to-noise ratio of the secondary user CR _i , and N represents the total number of all secondary users in the secondary user network where the secondary user CR _i is located; i=1,2,...,N, N≥3; Step 4-2, the secondary user base station calculates the normalized trust index of each user in all secondary user networks; where: the normalized trust index of the secondary user CR _i is denoted as ${\mathrm{<span\; class="notranslate">\; \&psi;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\frac{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}\underset{\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; i</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; SNR</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; SNR</span>}}_{\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\sqrt{\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; SNR</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; N</span>}}}}<span\; class="notranslate">\; ;</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{{\mathrm{<span\; class="notranslate">\; \&psi;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; \&psi;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; \&psi;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; ;</span>$ Step 4-3, the secondary user base station obtains the priority access index for each user to access the primary user network according to the obtained normalized interference factor and normalized trust index of each user; wherein, the secondary user CR _i accesses the primary user network The priority access index of the user network is denoted as ρ _i ; i=1,2,...,N, N≥3; is the normalized trust index of secondary user CR _i , is the normalized interference factor of the secondary user CR _i ; Step 4-4, the secondary user base station presets M alliance partition thresholds, and sets M+1 alliance partition segments as [-∞,λ ₁ ), [λ ₁ ,λ ₂ ),...,[λ _M-1 ,λ _M ) and [λ _M ,∞); wherein, the priority access index corresponding to the secondary user in the first alliance is in the [-∞,λ ₁ ) interval, and the priority access index corresponding to the secondary user in the second alliance The priority access index is in the [λ ₁ , λ ₂ ) interval, and so on. The priority access index corresponding to the secondary user in the Mth alliance is in the [λ _M-1 , λ _M The priority access index corresponding to the secondary users in the +1 alliance is in the [λ _M ,∞) interval segment, and each alliance is numbered in turn; Step 5, after each primary user base station searches for its dedicated secondary user network, when the secondary user in the secondary user network needs to use the frequency band for communication, the secondary user sends its alliance number to the secondary user base station, and the The secondary user base station sends a frequency band request to the corresponding paired primary user base station, so that the primary user base station can monitor the occupancy status of the authorized frequency bands used by each primary user in the primary user network, and send the monitored idle spectrum information to For the secondary user base station paired with the primary user base station: The primary user base station monitors the authorized frequency bands occupied by each primary user in the primary user network on the physical layer in real time to integrate the idle spectrum in the primary user network and identify the modulation of the primary user signal corresponding to each licensed frequency band mode, and the master user base station updates the idle spectrum it monitors in real time, and after uploading the latest idle spectrum of the master user base station to the MAC layer management, the master user base station will monitor the newly updated idle spectrum The information and the modulation mode of each primary user signal are forwarded to the secondary user base station paired with the primary user base station; Step 6: In the secondary user network where the secondary user that needs to use the frequency band to communicate is located, after the secondary user base station in the secondary user network receives the idle frequency spectrum and the primary user signal modulation method sent by the primary user base station, the secondary user base station The user base station generates multiple discontinuous idle frequency bands using OFDMA technology in the idle spectrum, and generates multiple frequency hopping patterns based on the generated idle frequency bands using frequency hopping technology, and according to the alliance number of the secondary user, the The secondary user base station dynamically allocates all the received primary user signal modulation modes and the generated frequency hopping patterns to the secondary users who need to use the frequency band for communication, and then the secondary users adjust their own signal modulation methods according to the received primary user signal modulation modes. Based on the modulation method of the primary user signal, the secondary user occupies different frequency bands for communication at different times according to the frequency hopping pattern, so as to meet the requirements of the secondary user to access the primary user network, so as to realize the non-interference access of the secondary user to the primary user network, so that the secondary user can use the free frequency band in the primary user network to communicate; Step 7: After the secondary user in step 6 completes the communication by using the frequency band, the secondary user sends notification information of vacating the frequency band and the alliance number to the secondary user base station in the secondary user network, so that the secondary user base station Send the feedback information that the secondary user has vacated the frequency band to the corresponding primary user base station; Step 8: After the primary user base station receives the feedback information about the frequency band vacated by the secondary user base station, if the primary user base station judges that the primary user to which the frequency band belongs has not requested to occupy this frequency band, the primary user base station will use the frequency band as a cross-band The standby frequency band accessed by the upper layer is used for subsequent access by secondary users who need frequency band communication; if the primary user base station judges that the primary user to which the frequency band belongs makes a request to occupy the frequency band, the primary user base station will feedback that the frequency band can be resumed. The information is sent to the main user to realize the normal use of the frequency band by the main user.