CN102223641A - Frequency spectrum access method and system based on frequency spectrum cavity nonuniformity - Google Patents

Abstract

The invention discloses a spectrum access method and system based on spectrum hole inhomogeneity. The method includes: calculating the channel capacity corresponding to the spectrum hole according to the preliminary detection result of the spectrum hole; The channel capacity is used to evaluate the spectrum holes, and the spectrum holes that cannot meet the user's transmission rate requirements are eliminated to obtain the re-selection results of the spectrum holes. Screen out the spectral holes in the uniform interval to obtain the screening sub-results of the spectral holes; select the spectral holes from the screening sub-results of the spectral holes and access them from users; preferably, select the spectral holes with the smallest channel capacity, and use the The user accesses the spectrum hole with the smallest channel capacity. The invention is beneficial to significantly improve the throughput and spectrum utilization rate of the slave system, thereby greatly reducing the call drop rate in the communication process of slave users.

Description

Spectrum access method and system based on spectrum hole inhomogeneity

technical field

The invention relates to spectrum access technology, in particular to a spectrum access method and system based on spectrum hole inhomogeneity.

Background technique

Improving the awareness of radio characteristics is conducive to improving the utilization of spectrum, so research on cognitive radio has become a hot research topic in this field in recent years. At present, research on cognitive radio is not just at the theoretical stage. The IEEE 802.22 working group is working on implementing cognitive radio in combination with many factors in the real environment. Among many factors, the difference (or inhomogeneity) of spectral holes is one of the factors that has attracted much attention.

C. Peng et al. regard the difference of spectrum hole as the variation of spectrum hole over time and space due to the main user’s business and mobile characteristics, and define the time-varying and space-varying nature of this spectrum hole as “spectrum Void Inhomogeneity". On this basis, the research on spectral hole inhomogeneity is used in channel selection, spectrum scheduling, dynamic control channel management, and spectrum sharing networks for Quality of Service (QoS) guarantees. Other studies on spectrum holes include Miao Ma et al. who defined channel inhomogeneity as the difference between the communication range and interference range of different spectrum holes, and based on this concept, they proposed a cross-layer designed Mesh network (a wireless mesh network). network) structure. The concept of channel inhomogeneity also involves the difference between non-uniformly used frequencies throughout the network, the packet error rate of different channels, and the difference in usage levels from users.

The previous research was based on the fact that all detected spectral holes can be used by secondary users, but in fact some of the detected holes cannot provide the capacity required by secondary users, so the resulting blocking and drop cannot be effectively avoided. Word problem. In addition, because the frequency between the spectrum holes (such as the center frequency of the spectrum hole) can be far away, the existing research results are difficult to solve the wireless parameters (mainly refers to the parameters of the wireless environment in the electromagnetic wave propagation environment, such as the electromagnetic wave propagation Blocking by buildings will lead to an increase in the propagation loss of electromagnetic waves) inaccurate and call drop caused by drastic changes in interference intensity. These technical problems make it difficult to improve the throughput and spectrum utilization of the slave system. Therefore, how to enable users to access appropriate spectrum holes has become an urgent technical problem to be solved in the spectrum access technology.

Contents of the invention

A technical problem to be solved by the present invention is to provide a spectrum access method based on the inhomogeneity of spectrum holes, so that slave users can access appropriate spectrum holes, thereby improving the throughput and spectrum utilization of the slave system.

One aspect of the present invention provides a spectrum access method based on spectrum hole inhomogeneity, the method includes: obtaining the preliminary detection result of the spectrum hole from the user's spectrum detection; calculating the corresponding spectrum hole according to the preliminary detection result of the spectrum hole Channel capacity: Evaluate the spectrum hole according to the user's transmission rate requirement and the channel capacity corresponding to the spectrum hole, and eliminate the spectrum hole that cannot meet the user's transmission rate requirement to obtain the re-selection result of the spectrum hole; calculate the user's current access The uniform interval of the spectrum hole, and filter the spectrum hole in the uniform interval from the check result of the spectrum hole to obtain the screening sub-result of the spectrum hole; select the spectrum hole from the screening sub-result of the spectrum hole and access it from the user, Preferably, the spectrum hole with the smallest channel capacity is selected, and the user accesses the spectrum hole with the smallest channel capacity.

In an embodiment of the spectrum access method based on spectrum hole inhomogeneity provided by the present invention, the method further includes: after removing the spectrum hole that cannot meet the transmission rate requirement of the user to obtain the reselection result of the spectrum hole, calculating the result from Before the uniform interval of the spectrum hole currently accessed by the user; judge whether the slave user needs to switch the spectrum hole; if the slave user needs to switch the spectrum hole, calculate the uniform interval of the spectrum hole currently accessed by the user; otherwise, The spectrum hole with the smallest channel capacity is selected from the selection results, and the user accesses the spectrum hole with the smallest channel capacity in the selection results.

In an embodiment of the spectrum access method based on spectrum hole inhomogeneity provided by the present invention, the method further includes: screening the spectrum holes in a uniform interval from the screening results of the spectrum holes to obtain the screening of the spectrum holes After the sub-results, before selecting the spectral hole with the smallest channel capacity from the screening sub-results of the spectral holes; judge whether the filtering sub-result is an empty set; if the filtering sub-result is an empty set, select the channel capacity in the double-check result of the spectral hole The smallest spectrum hole, and select the spectrum hole with the smallest channel capacity from the user access check result; otherwise, select the spectrum hole with the smallest channel capacity in the screening sub-result of the spectrum hole, and select the spectrum hole with the smallest channel capacity from the user access screening sub-result The spectral hole with the smallest channel capacity.

In an embodiment of the spectrum access method based on spectrum hole inhomogeneity provided by the present invention, the method calculates the channel capacity corresponding to the spectrum hole according to the preliminary detection result of the spectrum hole, combined with frequency factors and propagation environment factors.

In one embodiment of the spectrum access method based on the inhomogeneity of the spectrum hole provided by the present invention, the method calculates the center frequency of the spectrum hole currently accessed by the user by calculating the partial derivative of the channel capacity corresponding to the spectrum hole to the frequency in the uniform interval.

Another aspect of the present invention provides a spectrum access system based on spectrum hole inhomogeneity, the system includes: a spectrum detection module, used to perform spectrum detection, obtain the preliminary detection result of the spectrum hole, and send the preliminary detection result To the channel capacity calculation module; the channel capacity calculation module is used to receive the preliminary detection result sent by the spectrum detection module, and calculate the channel capacity corresponding to the spectrum hole according to the preliminary detection result; and send the channel capacity corresponding to the spectrum hole to the spectrum hole evaluation module The spectrum hole evaluation module is used to receive the channel capacity sent by the channel capacity calculation module, evaluate the spectrum hole according to the user's transmission rate requirement and channel capacity, and eliminate the spectrum hole that cannot meet the user's transmission rate requirement to obtain the spectrum hole The check result; and the check result is sent to the uniform interval calculation module; the uniform interval calculation module is used to receive the check result sent by the spectrum hole evaluation module, calculate the uniform interval of the spectrum hole currently accessed by the user, and from Screen out the spectral holes in the uniform interval in the check result to obtain the screening sub-results of the spectral holes; and send the screening sub-results to the spectrum hole access module; the spectrum hole access module is used to receive the uniform interval calculation module. Screening the sub-results, selecting a spectrum hole from the screening sub-results and accessing the secondary user, preferably, selecting the spectral hole with the smallest channel capacity, and accessing the spectral hole with the smallest channel capacity from the user.

In an embodiment of the spectrum access system based on spectrum hole inhomogeneity provided by the present invention, the system also includes: a spectrum hole switching judgment module, which is used to eliminate the spectrum that cannot meet the user's transmission rate requirements in the spectrum hole evaluation module After obtaining the check result of the spectrum hole, before sending the check result to the uniform interval calculation module, it is judged whether the slave user needs to switch the spectrum hole; if the slave user needs to switch the spectrum hole, the uniform interval calculation module calculates Otherwise, the spectrum hole access module selects the spectrum hole with the smallest channel capacity from the selection results of the spectrum holes, and accesses the spectrum hole with the smallest channel capacity from the selection results from the user.

In an embodiment of the spectrum access system based on spectrum hole inhomogeneity provided by the present invention, the system further includes: a spectrum hole switching judging module, which is used to select the After obtaining the screening sub-results of the spectral holes, before sending the screening sub-results to the spectrum hole access module, it is judged whether the screening sub-results are empty sets; if the filtering sub-results are empty sets, the spectral hole The access module selects the spectrum hole with the smallest channel capacity from the results of the spectrum hole selection, and will access the spectrum hole with the smallest channel capacity from the user access results; The spectrum hole with the smallest channel capacity is selected from the results, and the spectrum hole with the smallest channel capacity is selected from the user access screening sub-results.

In an embodiment of the spectrum access system based on spectrum hole inhomogeneity provided by the present invention, the channel capacity calculation module is further used to calculate the channel corresponding to the spectrum hole according to the preliminary detection results of the spectrum hole, combined with frequency factors and propagation environment factors capacity.

In an embodiment of the spectrum access system based on the inhomogeneity of the spectrum hole provided by the present invention, the uniform interval calculation module is further used to calculate the partial derivative of the frequency by the channel capacity corresponding to the spectrum hole, and calculate the current access from the user. The uniform interval in which the center frequency of the spectral hole lies.

The present invention provides a spectrum access method and system based on spectrum hole inhomogeneity, which considers the impact of spectrum hole inhomogeneity on secondary user communication when performing spectrum access, and satisfies the transmission rate of the secondary user. Selecting a suitable spectrum hole in the required spectrum hole for access will not cause waste of the spectrum hole capacity, but also can meet the user's transmission rate requirements. Furthermore, selecting the spectrum hole with the smallest channel capacity from the spectrum holes that meet the transmission rate requirements of the secondary user is beneficial to significantly improve the throughput and spectrum utilization of the secondary system, thereby greatly reducing the call drop rate of the secondary user during communication.

Description of drawings

Fig. 1 shows the schematic diagram of the interference temperature model in the prior art;

FIG. 2 shows a flowchart of a spectrum access method based on spectrum hole inhomogeneity provided by an embodiment of the present invention;

Fig. 3 shows a schematic diagram of the analysis of the influence of a single user scenario (i.e. a primary user and a secondary user interfering with each other) on the transmission power of the secondary system in the present invention;

Fig. 4 shows a schematic diagram of the impact analysis of the multi-user scenario (that is, multiple primary users and multiple secondary users interfere with each other) on the transmission power of the secondary system in the present invention;

FIG. 5 shows a schematic diagram of a uniform interval where the center frequency of the spectrum hole currently used by the user is located in the present invention;

FIG. 6 shows a flow chart of another embodiment of a spectrum access method based on spectrum hole inhomogeneity provided by the present invention;

FIG. 7 shows a flow chart of another embodiment of a spectrum access method based on spectrum hole inhomogeneity provided by the present invention;

FIG. 8 shows a flowchart of a specific embodiment of a spectrum access method based on spectrum hole inhomogeneity provided by the present invention;

FIG. 9 shows a schematic structural diagram of a spectrum access system based on spectrum hole inhomogeneity provided by an embodiment of the present invention;

Fig. 10 is a schematic structural diagram of another embodiment of a spectrum access system based on spectrum hole inhomogeneity provided by the present invention.

Detailed ways

The present invention pays attention to the difference that the spectrum hole is reflected when the spectrum hole is used by different users (SU, Secondary User) in the system (SS, Secondary System), that is, the inhomogeneity of the spectrum hole, specifically, the spectrum hole The main factors involved in the hole inhomogeneity include frequency, propagation environment, primary system (PS, Primary System), interference from the secondary system, and the like. The inhomogeneity of the spectrum hole also involves the time-varying and space-varying nature of the spectrum hole caused by the characteristics of the primary user (PU, Primary User) on the spectrum hole, the service and location distribution of the slave user, and the mutual interference factors between the master and slave users, etc. .

Spectral Hole Inhomogeneity Factor: Frequency Spread Characteristics

Electromagnetic wave propagation loss is reflected as the result of the combined effects of all propagation mechanisms and propagation environments, as shown in formula (1):

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; SR</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; ST</span>}}}{{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Among them, P _SR is the received power of the secondary system receiver (SR, Secondary Receiver), d is the distance between the transceivers of the secondary system, f represents the center frequency of the spectrum hole detected by the secondary system, and P _ST is the secondary system transmitter (ST , Secondary Transmitter), K is the path loss constant between user transceivers, m and n are the path loss index and frequency loss index respectively, and their values are determined by the specific environment.

According to formula (1), the received signal strength from the system is related to the transceiver distance, transmit power, carrier frequency and propagation environment. The transceiver distance and transmit power are set by the slave system, while the carrier frequency and propagation environment are affected by the selected spectrum hole and application environment respectively. The present invention focuses on the effects of frequency and propagation environment.

The frequency value is the most basic parameter of the spectral hole, and different spectral holes correspond to unique frequency values. Frequency changes affect the loss of signal propagation, which further affects the use of spectral holes by the slave system. The frequency factor affects the two parameters f and n in formula (1). Under the condition that the relative distance of the transceiver is constant, the higher the frequency, the greater the loss of the received signal and the lower the received signal strength. The center frequencies of spectral holes can vary widely, so the impact of frequency on signal transmission needs to be considered. The law that n is affected by frequency changes needs to analyze the relationship between different propagation modes and frequencies. The propagation modes of electromagnetic waves mainly include direct radiation, reflection, diffraction and penetration. The comparative relationship between frequency and transmission mode is shown in Table 1:

Propagation mode Frequency Range n direct shot Not limited by frequency treated as a constant reflection Not limited by frequency treated as a constant

Diffraction The diffraction effect of electromagnetic waves below 15GHz is obvious, and the diffracted electromagnetic waves can be used as a propagation path; but when the frequency is higher than 15GHz, the effect of electromagnetic wave diffraction is similar to the effect of reflection f is below 15GHz, n is regarded as a constant; f>15GHz, n suddenly increases penetrate As a result of the combined effect of electromagnetic wave penetration and loss in the medium, the penetration depth of frequencies above 10GHz to the surface with different humidity, seawater and pure water is almost zero f is below 10GHz, n is regarded as a constant; f>10GHz, n suddenly increases

Table 1 Correspondence between different propagation modes and frequencies

The propagation environment affects the degree of loss during wireless signal propagation. The transmission effects of the same spectrum hole used in different propagation environments are different, which also affects the selection of the spectrum hole by the slave system. In addition, the propagation path between transceivers may be blocked, such as buildings and mountains, and trees and vegetation. The combined effects of these factors form line-of-sight transmission (LOS, Line Of Sight) and non-line-of-sight transmission (NLOS, Non Line Of Sight). The path loss index m of the LOS environment is smaller than that of the NLOS environment.

Spectral Hole Inhomogeneity Factors: Primary User Characteristics

Factors affecting the inhomogeneity of spectrum holes also involve the characteristics of the primary user, such as the service and location distribution of the primary user, which is one of the important basis for the slave system to allocate spectrum holes. Among the characteristics of the primary user, the slave system mainly focuses on the processing method of the primary user for interference, especially the processing method of the interference generated by the secondary user. The interference temperature model proposed by the US Federal Communications Commission (FCC, Federal Communications Commission) is a widely accepted processing method. Fig. 1 shows a schematic diagram of a disturbance temperature model in the prior art. As shown in Figure 1, the interference temperature model requires that the sum of the additional interference generated by the secondary user and the original interference on the spectrum hole is lower than the interference temperature threshold (threshold) of the primary user receiver. That is, the additional interference generated by the secondary user is limited by the main user interference temperature threshold and the original interference. Therefore, the secondary user needs to consider two factors: on the one hand, ensure that the sum of the additional interference and the original interference is lower than the interference temperature threshold of the primary user, and on the other hand, ensure that the received interference is within the acceptable range of the secondary user.

The present invention will be described and illustrated more fully below with exemplary embodiments of the present invention with reference to the accompanying drawings.

Fig. 2 shows a flow chart of a spectrum access method based on spectrum hole inhomogeneity provided by an embodiment of the present invention.

As shown in FIG. 2 , the spectrum access method based on the heterogeneity of the spectrum hole includes step 202 , obtaining a preliminary detection result of the spectrum hole from the spectrum detection performed by the user. For example, the user first detects the spectrum holes currently provided by the system that can be used for access, and forms a preliminary detection result, which can also be called a primary set (P-Set, Prior Set). Those skilled in the art know that the commonly used spectrum detection methods mainly include detection methods such as matched filter detection, cyclostationary characteristic detection, and energy detection; The optimal choice; the energy detection method is a simplification of the matched filter detection method, and is the second-best choice for transmitter detection; the energy detection calculation complexity is low, and it does not need to know the physical layer and media access control layer information of the main system, such as Modulation type and order, pulse shaping, packet format, etc. For the specific detection implementation method, please refer to "Research on Spectrum Sensing Technology of Cognitive Radio" published by Tan Xuezhi, Institute of Communication Technology, Harbin Institute of Technology, in the third issue of "Communication Technology" in 2007.

In step 204, the channel capacity corresponding to the spectrum hole is calculated according to the preliminary detection result of the spectrum hole. For example, the channel capacity corresponding to each spectrum hole is calculated according to the aforementioned preliminary detection result P-Set, and the channel capacity C obtained from the user or the spectrum hole used by the system can be calculated by Shannon's theorem, as shown in formula (2).

$\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; B</span>}\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; P</span>}}{{\mathrm{<span\; class="notranslate">\; BN</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Among them, P is the average transmission power, and in the actual propagation environment, it is the received signal power P _SR from the user, N ₀ is the power spectral density of white noise, b is the bit "bit", and s is the second "second".

Next, an optimal way to calculate the channel capacity corresponding to the spectrum hole is briefly introduced. Preferably, the channel capacity corresponding to the spectrum hole is calculated according to the preliminary detection result of the spectrum hole in combination with frequency factors and propagation environment factors.

Specifically, when calculating the channel capacity of the spectrum hole by considering frequency factors and propagation environment factors, the aforementioned formula (1) is substituted into formula (2) to obtain formula (3); the details are as follows:

$\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; B</span>}\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; ST</span>}}}{{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; BN</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

When considering the impact of interference factors on the channel capacity that spectrum holes can provide, it is first necessary to analyze the interference. Specifically, the interference temperature mechanism is used to limit the interference generated by the slave system to the main system, and the relationship between the interference temperature and the strength of the interference signal around the receiver of the main system is shown in formula (4):

T = P _I /kB (4)

Among them, T is the interference temperature of the main system, k is the Boltzmann constant, B represents the bandwidth of the spectrum hole, and the interference power P _I of the main system is shown in formula (5):

P _I =P _{I_additional} +P _{I_original} (5)

Among them, _{PI_additional} is the additional interference caused by the secondary system using the spectrum hole to the primary user, and _{PI_original} is the original interference on the spectrum hole.

Fig. 3 shows a schematic diagram of the impact analysis on the transmission power of the secondary system in a single-user scenario (ie, a primary user and a secondary user interfere with each other) in the present invention. As shown in FIG. 3 , the primary user transmits signals through the spectrum hole f with the transmission power P _PT , and the interference intensity from the primary user to the secondary user is _{If_SU} . Therefore, P _{I_additional} and I _{f_SU} satisfy formula (6), as follows:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; P</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; additional</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; ST</span>}}}{{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}}\\ {\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PT</span>}}}{{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}}\end{array}\right.\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

According to the formula (6), the transmitted power P _ST from the user is obtained, and its specific expression is shown in the formula (7):

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; ST</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PT</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; additional</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

Among them, T _th is the interference temperature threshold of the master user, and P _th is the detection threshold of the slave user; as shown in Figure 3, the interference temperature threshold T _th represents the maximum interference intensity that the master user can bear, and the communication of the slave system should ensure that the master system The interference temperature is lower than T _th . As a spectrum hole, the interference of the primary user detected by the secondary user is lower than the detection threshold P _th of the secondary user. Therefore, the boundary conditions of Equation (7) are as follows:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; the\; th</span>}}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; additional</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; th</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; kB</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; original</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

Fig. 4 is a schematic diagram showing the impact analysis of the transmission power of the secondary system in a multi-user scenario (that is, multiple primary users and multiple secondary users interfere with each other) in the present invention. As shown in Figure 4, in a multi-user scenario, the signal transmitted by each secondary user will reach all primary users and cause interference, so formula (6) is correspondingly modified into formula (9), as follows:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; P</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; additional</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; ST</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}{{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}}\\ {\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PT</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>}{{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}}\end{array}\right.<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

The boundary conditions corresponding to formula (9) are shown in formula (10):

$\left\{\begin{array}{c}\underset{\mathrm{<span\; class="notranslate">\; j</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">\; P</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; additional</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; kB</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; original</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>\\ \underset{\mathrm{<span\; class="notranslate">\; j</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">\; P</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; additional</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; th</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; kB</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; original</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>\\ \underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; the\; th</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

Among them, j ∈ [1, N] and i ∈ [1, L] represent different slave users and master users respectively, and N is the number of slave users using frequency f as a spectrum hole in a certain geographical range (for example, in a radius of 1km In the area, if the slave users use the same spectrum hole, then there will be mutual influence between the slave users, and if a slave user 100km away also uses the same spectrum hole, since it is not in the affected area, then the It is not considered; the specific distance value is to be determined according to the wireless environment of the transmit power of the secondary user, and this is only an example), and L is the number of primary users corresponding to the authorized frequency f.

Divide each group of equations in formula (9) to obtain the transmit power from the user, as shown below:

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; ST</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; \&times;</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PT</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; additional</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

The interference intensity of the spectrum hole at the current geographic space position is added to the calculation formula (3) of the channel capacity of the system to obtain the formula (12), which is as follows:

$\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; B</span>}\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; ST</span>}}}{{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; CR</span>}}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 12</span>}<span\; class="notranslate">\; )</span>$

Substitute formula (7) into formula (12) to get the channel capacity in the single-user scenario, as shown in formula (13):

$\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; B</span>}\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PT</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; additional</span>}}}{{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; BN</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 13</span>}<span\; class="notranslate">\; )</span>$

Substitute formula (9) into formula (12) to get the channel capacity in the multi-user scenario, as shown in formula (14):

$\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; B</span>}\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\underset{\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PT</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; additional</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; d</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; BN</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 14</span>}<span\; class="notranslate">\; )</span>$

Equation (14) characterizes the difference in channel capacity caused by spectral hole inhomogeneity, from which those skilled in the art can know: there are different master-slave user distributions for different frequencies, resulting in different slave users using the same spectrum hole to obtain capacity varies.

Step 206: Evaluate the spectrum hole according to the transmission rate requirement of the slave user and the channel capacity corresponding to the spectrum hole, and eliminate the spectrum hole that cannot meet the transmission rate requirement of the slave user to obtain a re-selection result of the spectrum hole. For example, according to the user's transmission rate requirements and the actual calculation of the channel capacity corresponding to each spectrum hole, each spectrum hole is evaluated, so that the spectrum holes that cannot meet the user's transmission rate requirements are excluded from the primary selection set P-Set , and the remaining spectral holes form the result of the multiple selection, which can also be called the multiple selection set (E-Set, Evolution Set).

Step 208: Calculate the uniform interval of the spectral holes currently accessed by the user, and filter out the spectral holes in the uniform interval from the selection results of the spectral holes to obtain the screening sub-results of the spectral holes. Specifically, for a secondary user who needs to switch a spectrum hole, it is not only necessary to meet the transmission rate requirement of the secondary user, but also to ensure that the switching target spectrum hole is close to the frequency of the currently serving spectrum hole. Inaccurate wireless parameters and high interference levels are the main reasons for the failure of spectrum hole handover. If the frequency difference between the target spectrum hole and the current service spectrum hole is large, the path loss model will change. At this time, spectrum hole Handover may cause a large difference in the wireless environment estimation performed by the user. Moreover, in the case of a large frequency difference before and after the spectrum hole switching, factors such as Doppler frequency shift cannot be ignored. In addition, since the licensed frequency bands of the primary system are mostly continuous, the service and distribution characteristics of the primary users corresponding to the similar spectrum holes are likely to be relatively close; therefore, the reliability of the spectrum holes with similar frequencies is greater than that of the spectrum far apart. Reliability of spectral holes. Moreover, due to the change of the characteristics of the primary user, the interference level received by the secondary user from the primary user may be greater than before, which is also one of the reasons for the handover failure. Therefore, frequency selection needs to be performed during the spectrum hole access process of handover users.

Next, an optimal way to calculate the channel capacity corresponding to the spectrum hole is briefly introduced. Preferably, the uniform interval where the center frequency of the spectrum hole currently accessed by the user is calculated. There are many calculation methods for the uniform interval, and the purpose of determining this interval is to reduce the probability of handover spectrum hole failure.

In an embodiment of the calculation of the uniform interval provided by the present invention, the channel capacity corresponding to the spectrum hole is calculated by calculating the partial derivative with respect to the frequency. Specifically, after taking the aforementioned formula (8) into the formula (7), the maximum capacity that the spectrum hole can provide in a single-user scenario can be obtained, as shown in formula (15):

$\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; B</span>}\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PT</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; th</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; kB</span>}}{{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; BN</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 15</span>}<span\; class="notranslate">\; )</span>$

的计算比较困难，这是因为K、m和n都是频谱空洞频率f的函数，并随f的变化而变化。然而，在较短时间内，通信环境的变化可以忽略不计，因此m和K可以被视为常数。现有的无线系统的频率大多在10GHz以下，因此n也可以看作常数。I_{f_SU}、N₀和P_PT取决于主从用户的地理分布，因此在计算过程中也可以简化为常数。由此，我们得到频谱空洞的信道容量对频率求偏导数的表达式，如公式(16)所示：usually,

The calculation of is more difficult, because K, m and n are all functions of the spectral hole frequency f, and change with the change of f. However, in a short period of time, the change of the communication environment is negligible, so m and K can be regarded as constants. The frequencies of existing wireless systems are mostly below 10 GHz, so n can also be regarded as a constant. I _{f_SU} , N ₀ and P _PT depend on the geographical distribution of master and slave users, so they can also be simplified to constants in the calculation process. From this, we get the expression of the partial derivative of the channel capacity of the spectral hole with respect to the frequency, as shown in formula (16):

$\frac{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; C</span>}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PT</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; th</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; ln</span>}\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; BN</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; -</span>}\mathrm{<span\; class="notranslate">\; SU</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PT</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; th</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; ]</span>}\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 16</span>}<span\; class="notranslate">\; )</span>$

进而得到该频谱空洞中心频率所处的均匀区间的频率范围。According to the aforementioned formula (16), calculate the corresponding

Furthermore, the frequency range of the uniform interval in which the center frequency of the spectrum hole is located is obtained.

决定的均匀区间的范围；

为当前的偏导的值，

为偏导数的门限所决定的偏导范围，也就是说

由于现实的从系统中

并不是单调的，因此，图5中所示的曲线也可能不是单调的，也就是说，可能存在多个频率区间满足

的要求，所以要在横轴加入频率变化门限的限制才能够得到正确的均匀区间，例如根据从用户传输速率需求加入(Δf)th的限制确定均匀区间。Fig. 5 shows a schematic diagram of a uniform interval where the central frequency of the spectrum hole currently used by the user is located in the present invention. As shown in Figure 5, where f ₀ represents the center frequency of the spectrum hole currently used by the user, [f ₁ , f ₂ ] is

Determine the range of the uniform interval;

is the current value of the partial derivative,

The partial derivative range determined by the threshold of the partial derivative, that is to say

Due to the fact that from the system

is not monotonic, therefore, the curve shown in Figure 5 may not be monotonic, that is, there may be multiple frequency intervals satisfying

Therefore, the correct uniform interval can be obtained only by adding a frequency change threshold limit on the horizontal axis, for example, the uniform interval can be determined by adding the (Δf)th limit from the user transmission rate requirement.

In another embodiment of the calculation of the uniform interval provided by the present invention, it is calculated by means of the difference between the channel capacity corresponding to the spectrum hole and the transmission rate requirement of the user. Specifically, the channel capacity of the spectrum hole is calculated according to the aforementioned formula (15), and a uniform interval threshold ΔC _th is set. ΔC _th and the slave user transmission rate requirement R _SUrequire form a range of hole capacity in a uniform interval [R _SUrequire -ΔC _th , R _SUrequire +ΔC _th ]. Select the spectrum hole whose capacity is within this range from the spectrum hole check result as the sub-result of uniform interval screening. If the result is an empty set, the spectral holes in this range are selected again from the preliminary detection results of the spectral holes as the screening sub-results of the uniform interval.

For the multi-user scenario, it can be regarded as a combination of multiple single-user scenarios; the derivation of its uniform interval is more complicated than that of the single-user scenario, and the multi-user scenario should be based on the analysis of the single-user scenario. Analysis, but the principle is the same as the single-user scenario, and the methods used for analysis are roughly the same.

Step 210: Select a spectrum hole with a suitable channel capacity from the screening sub-results of the spectrum hole, and access the spectrum hole with a corresponding channel capacity from the user. For example, the user selects a suitable spectrum hole in the final screening sub-results for access, which can meet the communication capacity requirements of the user; after the screening of the aforementioned process, the spectrum holes in the screening sub-results can all meet the communication capacity requirements of the user. Therefore, selecting an appropriate spectrum hole can be understood as selecting any one of the spectrum holes for handover and access. Preferably, implement the most appropriate selection principle (APP-Selection, Appropriate Selection; that is, select the spectrum hole with the smallest capacity in the spectrum hole set) to select the spectrum hole with the smallest channel capacity in the screening sub-results as the access hole from the user.

The spectrum access method based on the inhomogeneity of spectrum holes provided by the present invention considers the influence of the inhomogeneity of spectrum holes on the communication of secondary users when performing spectrum access. Select an appropriate spectrum hole (preferably select the spectrum hole with the smallest channel capacity) for access, which will not cause waste of spectrum hole capacity, and can meet the transmission rate requirements of users. According to the teaching of the present invention, those skilled in the art can clearly know that the spectrum access scheme based on the inhomogeneity of the spectrum hole provided by the present invention is beneficial to significantly improve the throughput and spectrum utilization of the slave system, thereby greatly reducing the frequency of slave user communication. call drop rate during the process.

Fig. 6 shows a flow chart of another embodiment of a spectrum access method based on spectrum hole inhomogeneity provided by the present invention.

As shown in FIG. 6 , the spectrum access method flow 600 based on spectrum hole inhomogeneity includes: steps 602-612, wherein steps 602-606, 608 and 610 can be performed the same as steps 202-210 shown in FIG. 2 or For similar technical content, for the sake of brevity, the technical content will not be repeated here.

As shown in Figure 6, after step 606 of "removing the spectrum holes that cannot meet the user's transmission rate requirements to obtain the check result of the spectrum hole", step 608 of "calculate the uniform interval of the spectrum hole currently accessed by the user" Before that, step 607 is executed to determine whether the slave user needs to switch spectrum holes. If the secondary user needs to switch spectrum holes, go to step 608; otherwise, go to step 612.

Step 612: Select the spectrum hole with the smallest channel capacity from the re-selected results of the spectrum holes, and access the spectrum hole with the smallest channel capacity from the re-selected results from the user. Specifically, since different spectrum holes can bring different channel capacities to secondary users, in the process of spectrum access, the channel capacity of the spectrum hole needs to be used as the criterion for determining whether the spectrum hole can meet the needs of secondary users. When the user who implements spectrum hole access is a new user, it is only necessary to ensure that the accessed spectrum hole can meet the user's capacity requirements, without the need to switch users (not only to meet the transmission rate requirements of the user, but also to The requirement to ensure that the frequency of the target spectrum hole for switching is close to the frequency of the serving spectrum hole). Based on the aforementioned reasons, when the secondary user is a newly accessed user (non-handover user), then select an appropriate spectrum hole in the reselection result E-Set to access, because in step 606, the spectrum that does not meet the capacity requirement has been allocated Holes are eliminated, so the spectrum holes selected in the check result E-Set can all meet the user's transmission rate requirements. Preferably, the most appropriate selection principle APP-Selection is implemented to select the spectrum hole with the smallest channel capacity, which can meet the transmission rate requirements of the user without causing waste of capacity.

The spectrum access method based on the inhomogeneity of the spectrum holes provided by the present invention, after evaluating the spectrum holes and eliminating the spectrum holes that cannot meet the transmission rate requirements of the slave users, judges whether the slave users need to switch the spectrum holes, according to whether the slave users are The newly connected user is still waiting to be switched. The secondary user selects the appropriate spectrum hole for access from different screening results, thereby significantly improving the throughput and spectrum utilization of the secondary system, and greatly reducing the call drop rate of the secondary user during communication. .

Fig. 7 shows a flow chart of another embodiment of a spectrum access method based on spectrum hole inhomogeneity provided by the present invention.

As shown in FIG. 7 , the spectrum access method flow 600 based on spectrum hole inhomogeneity includes: steps 702-712, wherein steps 702-708 and 710 can perform the same or similar steps as steps 202-210 shown in FIG. For the sake of brevity, the technical content will not be repeated here.

As shown in FIG. 7 , after the step 708 of "screening the spectral holes in the uniform interval from the screening results of the spectral holes to obtain the screening sub-results of the spectral holes", the step 710 of "from the screening sub-results of the spectral holes Before selecting the spectrum hole with the smallest channel capacity", step 709 is executed to determine whether the screening sub-result is an empty set. If the screening result is an empty set, go to step 712; otherwise, go to step 710.

Step 712: Select the spectrum hole with the smallest channel capacity from the rechecked results of the spectrum holes, and access the spectrum hole with the smallest channel capacity from the rechecked results from the user. Specifically, if the screening sub-result Sub-Set is an empty set, it means that there is no spectral hole that meets the requirements in the uniform interval calculated in step 708; It can meet the transmission rate requirements of users. Preferably, the most appropriate selection principle APP-Selection is implemented to select the spectrum hole with the smallest channel capacity, which can meet the transmission rate requirements of the user without causing waste of capacity.

The spectrum access method based on the inhomogeneity of the spectrum holes provided by the present invention, after screening out the spectrum holes in the uniform interval from the re-selection results of the spectrum holes to obtain the screening sub-results of the spectrum holes, judge the final screening sub-results Whether it is an empty set, and according to the judgment result, select a suitable spectrum hole from different screening results for access, thereby significantly improving the throughput and spectrum utilization of the slave system, and greatly reducing the call drop rate of the slave user during communication.

Fig. 8 shows a flow chart of a specific embodiment of a spectrum access method based on spectrum hole inhomogeneity provided by the present invention.

As shown in FIG. 8 , the spectrum access method based on the heterogeneity of the spectrum hole includes step 802 , obtaining a preliminary detection result of the spectrum hole from the spectrum detection performed by the user. For example, the user first detects the spectrum holes currently provided by the system that can be used for access, and forms a preliminary detection result, which can also be called a primary set (P-Set, Prior Set).

Step 804, calculate the channel capacity corresponding to the spectrum hole according to the preliminary detection result of the spectrum hole. For example, the channel capacity corresponding to each spectrum hole is calculated according to the aforementioned preliminary detection result P-Set, and the channel capacity C obtained from the user or the spectrum hole used by the system can be calculated by Shannon's theorem. Preferably, according to the preliminary detection of the spectrum hole As a result, the channel capacity corresponding to the spectrum hole is calculated in combination with the frequency factor and the propagation environment factor; for the specific calculation method, please refer to the detailed introduction in the aforementioned step 204, which will not be repeated here.

Step 806: Evaluate the spectrum hole according to the transmission rate requirement of the slave user and the channel capacity corresponding to the spectrum hole, and eliminate the spectrum hole that cannot meet the transmission rate requirement of the slave user to obtain a re-selection result of the spectrum hole. For example, according to the user's transmission rate requirements and the actual calculation of the channel capacity corresponding to each spectrum hole, each spectrum hole is evaluated, so that the spectrum holes that cannot meet the user's transmission rate requirements are excluded from the primary selection set P-Set , and the remaining spectral holes form the result of the multiple selection, which can also be called the multiple selection set (E-Set, Evolution Set).

Step 807, judging whether the secondary user needs to switch spectrum holes. Specifically, since different spectrum holes can bring different channel capacities to secondary users, in the process of spectrum access, the channel capacity of the spectrum hole needs to be used as the criterion for determining whether the spectrum hole can meet the needs of secondary users. When the user who implements spectrum hole access is a new user, it is only necessary to ensure that the accessed spectrum hole can meet the user's capacity requirements, without the need to switch users (not only to meet the transmission rate requirements of the user, but also to Ensure that the frequency of the target spectrum hole for switching is close to the frequency of the serving spectrum hole); therefore, step 807 is executed after step 806, and step 812 is executed according to the secondary user being a new access user; if there is a requirement for switching the spectrum hole If the slave user is selected, step 808 is performed.

Step 808: Calculate the uniform interval of the spectral holes currently accessed by the user, and filter out the spectral holes in the uniform interval from the checked results of the spectral holes to obtain the screening sub-results of the spectral holes. Specifically, for a secondary user who needs to switch a spectrum hole, it is not only necessary to meet the transmission rate requirement of the secondary user, but also to ensure that the switching target spectrum hole is close to the frequency of the currently serving spectrum hole. Inaccurate wireless parameters and high interference levels are the main reasons for the failure of spectrum hole handover. If the frequency difference between the target spectrum hole and the current service spectrum hole is large, the path loss model will change. At this time, spectrum hole Handover may cause a large difference in the wireless environment estimation performed by the user. Moreover, in the case of a large frequency difference before and after the spectrum hole switching, factors such as Doppler frequency shift cannot be ignored. In addition, since the licensed frequency bands of the primary system are mostly continuous, the service and distribution characteristics of the primary users corresponding to the similar spectrum holes are likely to be relatively close; therefore, the reliability of the spectrum holes with similar frequencies is greater than that of the spectrum far apart. Reliability of spectral holes. Therefore, it is necessary to select a frequency during the spectrum hole access process of switching users; for the specific calculation method, please refer to the detailed introduction in the aforementioned step 208, which will not be repeated here.

Step 809, judging whether the screening sub-result is an empty set. If the screening sub-result is an empty set, go to step 812; otherwise, go to step 810.

Step 810: Select the spectrum hole with the smallest channel capacity from the screening sub-results of the spectrum holes, and access the spectrum hole with the smallest channel capacity from the user. For example, implement the most appropriate selection principle (APP-Selection, Appropriate Selection; that is, select the spectrum hole with the smallest capacity in the spectrum hole set) from the user in the final screening sub-result to select the spectrum hole with the smallest channel capacity in the screening sub-result as the user’s access hole.

Step 812: Select the spectrum hole with the smallest channel capacity from the rechecked results of the spectrum holes, and access the spectrum hole with the smallest channel capacity from the rechecked results from the user. Specifically, if the screening sub-result Sub-Set is an empty set, it means that there is no spectral hole that meets the requirements in the uniform interval calculated in step 808; In the E-Set, the spectral hole with the smallest channel capacity is selected, which can not only meet the user's transmission rate requirements, but also not cause waste of capacity.

FIG. 9 shows a schematic structural diagram of a spectrum access system based on spectrum hole inhomogeneity provided by an embodiment of the present invention.

As shown in Fig. 9, a spectrum access system 900 based on spectrum hole inhomogeneity includes: a spectrum detection module 902, a channel capacity calculation module 904, a spectrum hole evaluation module 906, a uniform interval calculation module 908 and a spectrum hole access module 910.

Wherein, the spectrum detection module 902 is configured to perform spectrum detection and obtain preliminary detection results of spectrum holes. For example, the spectrum detection module first detects the spectrum holes that the system can currently provide that can be used for access, forms a preliminary detection result, which can also be called a primary selection set (P-Set, Prior Set), and sends the preliminary detection result to the channel capacity calculation module 904 .

The channel capacity calculation module 904 is configured to receive the preliminary detection result sent by the spectrum detection module 902, and calculate the channel capacity corresponding to the spectrum hole according to the preliminary detection result of the spectrum hole; and send the channel capacity corresponding to the spectrum hole to the spectrum hole evaluation module 906. For example, according to the preliminary detection result P-Set obtained by the spectrum detection module 902, the channel capacity corresponding to each spectrum hole is calculated respectively, and the channel capacity obtained from the spectrum hole used by the user or the system can be calculated by Shannon's theorem. Preferably, the channel capacity calculation module 904 calculates the channel capacity corresponding to the spectrum hole according to the preliminary detection result of the spectrum hole, combined with frequency factors and propagation environment factors; the specific calculation method refers to the detailed introduction in the aforementioned step 204, and will not be repeated here.

The spectrum hole evaluation module 906 is used to receive the channel capacity sent by the channel capacity calculation module 904, evaluate the spectrum hole according to the transmission rate requirement and the channel capacity of the secondary user, and eliminate the spectral hole that cannot meet the transmission rate requirement of the secondary user to obtain the spectrum empty check result; and send the check result to the uniform interval calculation module 908. For example, according to the user's transmission rate requirements and the actual calculation of the channel capacity corresponding to each spectrum hole by the channel capacity calculation module, the spectrum hole evaluation module evaluates each spectrum hole, so that the spectrum holes that cannot meet the user's transmission rate requirements are removed from Excluded from the primary selection set P-Set, the remaining spectrum holes form the re-selection result, which can also be called the re-selection set (E-Set, Evolution Set), and the re-selection result is sent to the uniform interval calculation module.

The uniform interval calculation module 908 is configured to receive the check result sent by the spectrum hole evaluation module 906, calculate the uniform interval of the spectrum hole currently accessed by the user, and filter out the spectrum hole in the uniform interval from the check result to obtain The screening sub-result of the spectrum hole; and sending the screening sub-result to the spectrum hole access module 910 . Specifically, for a secondary user who needs to switch a spectrum hole, it is not only necessary to meet the transmission rate requirement of the secondary user, but also to ensure that the switching target spectrum hole is close to the frequency of the currently serving spectrum hole. If the frequencies of the target spectrum hole and the frequency of the current service spectrum hole are greatly different, the path loss model will change, and switching the spectrum hole at this time may cause a large difference in the estimation of the wireless environment from the user. Moreover, in the case of a large frequency difference before and after the spectrum hole switching, factors such as Doppler frequency shift cannot be ignored. In addition, since the licensed frequency bands of the primary system are mostly continuous, the service and distribution characteristics of the primary users corresponding to the similar spectrum holes are likely to be relatively close; therefore, the reliability of the spectrum holes with similar frequencies is greater than that of the spectrum far apart. Reliability of spectral holes. Therefore, frequency selection needs to be performed during the spectrum hole access process of handover users. Preferably, the uniform interval calculation module 908 calculates the channel capacity corresponding to the spectrum hole to the frequency partial derivative, or the difference between the channel capacity corresponding to the spectrum hole and the transmission rate requirement of the user to calculate the current access rate of the slave user. The uniform interval in which the center frequency of the spectrum hole of , for the specific calculation method, refer to the detailed introduction in the aforementioned step 208 , which will not be repeated here.

The spectrum hole access module 910 is used to receive the screening sub-results sent by the uniform interval calculation module 908, select a spectrum hole from the screening sub-results and access the secondary user; preferably, select the spectral hole with the smallest channel capacity, and transfer the secondary user Access the spectral hole with the smallest channel capacity. For example, the spectrum hole access module selects a suitable spectrum hole in the final screening sub-result for access, and the accessed spectrum hole can meet the communication capacity requirements of the user; after the screening of the aforementioned process, the spectrum hole in the screening sub-result All of them can meet the communication capacity requirements of the secondary users. Therefore, selecting an appropriate spectrum hole can be understood as selecting any spectrum hole for handover access. Preferably, the most appropriate selection principle APP-Selection is implemented to select the spectrum hole with the smallest channel capacity in the screening sub-results as the access hole for the secondary user.

The spectrum access system based on the inhomogeneity of spectrum holes provided by the present invention considers the influence of the inhomogeneity of spectrum holes on the communication of secondary users when performing spectrum access. Select an appropriate spectrum hole (preferably select the spectrum hole with the smallest channel capacity) for access, which will not cause waste of spectrum hole capacity, and can meet the transmission rate requirements of users. According to the teaching of the present invention, those skilled in the art can clearly know that the spectrum access scheme based on the inhomogeneity of the spectrum hole provided by the present invention is beneficial to significantly improve the throughput and spectrum utilization of the slave system, thereby greatly reducing the frequency of slave user communication. call drop rate during the process.

Fig. 10 is a schematic structural diagram of another embodiment of a spectrum access system based on spectrum hole inhomogeneity provided by the present invention.

As shown in Figure 10, a spectrum access system 1000 based on spectrum hole inhomogeneity includes: a spectrum detection module 1002, a channel capacity calculation module 1004, a spectrum hole evaluation module 1006, a spectrum hole switching judgment module 1007, and a uniform interval calculation module 1008 and a spectrum hole access module 1010. Wherein the spectrum detection module 1002, the channel capacity calculation module 1004, the spectrum hole evaluation module 1006, the uniform interval calculation module 1008 and the spectrum hole access module 1010 can be the same as the spectrum detection module 902 shown in Figure 9, the channel capacity calculation module 904, the spectrum hole The evaluation module 906, the uniform interval calculation module 908 and the spectrum hole access module 910 have the same or similar functional modules. For the sake of brevity, no more details are given here.

As shown in FIG. 10 , the spectrum access system 1000 based on spectrum hole inhomogeneity also includes: a spectrum hole switching judgment module 1007, which is used to eliminate spectrum holes that cannot meet the user's transmission rate requirements in the spectrum hole evaluation module 1006 and obtain spectrum After the check result of the hole, it is judged whether the slave user needs to switch the spectrum hole; if the slave user needs to switch the spectrum hole, the uniform interval calculation module calculates the uniform interval of the spectrum hole currently accessed by the slave user; otherwise, when the slave user is a new A user (non-handover user) who accesses, then selects a suitable spectrum hole in the reselection result E-Set to access, because the spectrum hole evaluation module 1006 has excluded the spectrum hole that does not meet the capacity requirement, so in the reselection As a result, the spectrum holes selected in E-Set can meet the transmission rate requirements of users. Preferably, the most appropriate selection principle APP-Selection is implemented to select the spectrum hole with the smallest channel capacity, which can meet the transmission rate requirements of the user without causing waste of capacity.

In an embodiment of the spectrum access system based on spectrum hole inhomogeneity provided by the present invention, the spectrum hole switching judgment module is further used to filter out the spectrum in the uniform interval from the re-selection results of the spectrum holes in the uniform interval calculation module After emptying to obtain the screening sub-results of spectrum holes, it is judged whether the screening sub-results are empty sets; if the screening sub-results are empty sets, the spectrum hole access module selects the spectrum holes with the smallest channel capacity in the selection results of spectrum holes , and will access the spectrum hole with the smallest channel capacity from the user access check result; otherwise, if the screening sub-result Sub-Set is an empty set, it means that the uniform interval calculated by the uniform interval calculation module does not meet the requirements The spectrum holes; then the spectrum holes selected in the check result E-Set can meet the transmission rate requirements of the users. Preferably, the most appropriate selection principle APP-Selection is implemented to select the spectrum hole with the smallest channel capacity, which can meet the transmission rate requirements of the user without causing waste of capacity.

The present invention focuses on frequency, propagation environment and interference of the master-slave system and other factors that lead to the inhomogeneity of the spectrum hole when studying the inhomogeneity of the spectrum hole (the difference when the spectrum hole is used by different slave systems). Calculate the spectrum hole capacity based on the inhomogeneity of the spectrum hole and propose a new spectrum hole allocation scheme, which can effectively avoid selecting unavailable spectrum holes from the system and allocate the detected spectrum holes more reasonably, and finally improve the spectrum utilization. . With reference to the foregoing exemplary description of the present invention, those skilled in the art can clearly understand that the present invention has the following advantages:

The invention discloses a spectrum access method and system based on spectrum hole inhomogeneity, which considers the impact of spectrum hole inhomogeneity on slave user communication when performing spectrum access, and satisfies the transmission rate of the slave user. Selecting a suitable spectrum hole in the required spectrum hole for access will not cause waste of the spectrum hole capacity, but also can meet the user's transmission rate requirements.

The invention discloses a spectrum access method and system based on the inhomogeneity of spectrum holes. Selecting the spectrum hole with the smallest channel capacity from the spectrum holes that meet the transmission rate requirements of the slave user is beneficial to significantly improve the throughput and spectrum of the slave system. Utilization, thereby greatly reducing the call drop rate from the user communication process.

The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and changes will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to better explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention and design various embodiments with various modifications as are suited to the particular use.

Claims (10)

1. A spectrum access method based on spectrum hole inhomogeneity, characterized in that the method comprises: Obtain the preliminary detection result of the spectrum hole from the spectrum detection performed by the user; calculating the channel capacity corresponding to the spectrum hole according to the preliminary detection result of the spectrum hole; Evaluate the spectrum hole according to the transmission rate requirement of the slave user and the channel capacity corresponding to the spectrum hole, and eliminate the spectrum hole that cannot meet the transmission rate requirement of the slave user to obtain a re-selection result of the spectrum hole; calculating the uniform interval of the spectral holes currently accessed by the user, and screening out the spectral holes within the uniform interval from the check results of the spectral holes to obtain the filtering sub-results of the spectral holes; Selecting a spectrum hole from the screening sub-results of the spectrum hole and accessing the secondary user, preferably, selecting a spectrum hole with the smallest channel capacity, and connecting the secondary user to the spectrum hole with the smallest channel capacity. 2. The method according to claim 1, characterized in that, the method further comprises: after eliminating the spectral holes that cannot meet the transmission rate requirements of the secondary users to obtain the check result of the spectral holes, calculating the secondary user Before the uniform interval of the currently accessed spectrum hole; determine whether the slave user needs to switch the spectrum hole; If the slave user needs to switch the spectrum hole, calculate the uniform interval of the spectrum hole currently accessed by the slave user; Otherwise, select the spectrum hole with the smallest channel capacity from the re-selection results of the spectrum holes, and connect the secondary user to the spectrum hole with the smallest channel capacity among the re-selection results. 3. The method according to claim 1, characterized in that, the method further comprises: screening out the spectral holes in the uniform interval from the check results of the spectral holes to obtain the filter of the spectral holes After the result, before selecting the spectral hole with the smallest channel capacity from the screening sub-results of the spectrum hole; judging whether the screening sub-result is an empty set; If the screening sub-result is an empty set, selecting the spectrum hole with the smallest channel capacity in the selection result of the spectrum hole, and accessing the spectrum hole with the smallest channel capacity in the selection result from the user; Otherwise, select a spectrum hole with the smallest channel capacity from the screening sub-results of the spectrum holes, and connect the secondary user to the spectrum hole with the smallest channel capacity in the screening sub-results. 4. The method according to claim 1, wherein the step of calculating the channel capacity corresponding to the spectral hole according to the preliminary detection result of the spectral hole further comprises: according to the preliminary detection result of the spectral hole, The channel capacity corresponding to the spectrum hole is calculated in combination with the frequency factor and the propagation environment factor. 5. The method according to claim 1, wherein the step of calculating the uniform interval of the spectrum hole currently accessed by the user further comprises: By calculating the partial derivative of the channel capacity corresponding to the spectral hole with respect to frequency, or by using the difference between the channel capacity corresponding to the spectral hole and the transmission rate requirement of the secondary user, calculate the value of the spectral hole currently accessed by the secondary user The uniform interval in which the center frequency lies. 6. A spectrum access system based on spectrum hole inhomogeneity, characterized in that the system comprises: A spectrum detection module, configured to perform spectrum detection, obtain preliminary detection results of spectrum holes, and send the preliminary detection results to the channel capacity calculation module; The channel capacity calculation module is configured to receive the preliminary detection result sent by the spectrum detection module, and calculate the channel capacity corresponding to the spectrum hole according to the preliminary detection result; and calculate the channel capacity corresponding to the spectrum hole Send to the spectrum hole evaluation module; A spectrum hole evaluation module, configured to receive the channel capacity sent by the channel capacity calculation module, evaluate the spectrum hole according to the transmission rate requirement of the secondary user and the channel capacity, and eliminate the channel capacity that cannot meet the requirements of the secondary user. The frequency spectrum hole required by the transmission rate to obtain the check result of the spectrum hole; and send the check result to the uniform interval calculation module; The uniform interval calculation module is configured to receive the re-selection result sent by the spectrum hole evaluation module, calculate the uniform interval of the spectrum hole currently accessed by the user, and filter out from the re-selection result the Spectrum holes in the uniform interval to obtain the screening sub-results of the spectrum holes; and sending the screening sub-results to the spectrum hole access module; The spectrum hole access module is configured to receive the screening sub-result sent by the uniform interval calculation module, select a spectrum hole from the screening sub-result and access the secondary user, preferably, select the channel with the smallest capacity spectrum hole, and the secondary user accesses the spectrum hole with the smallest channel capacity. 7. The system according to claim 6, characterized in that, the system further comprises: a spectrum hole switching judging module, which is used to eliminate the spectrum holes that cannot meet the transmission rate requirements of the secondary user in the spectrum hole evaluation module After obtaining the re-selection result of the spectrum hole, before the re-selection result is sent to the uniform interval calculation module, it is judged whether the user needs to switch the spectrum hole; if the user needs to switch the spectrum hole, the uniform interval The calculation module calculates the uniform interval of the spectrum hole currently accessed by the slave user; otherwise, the spectrum hole access module selects the spectrum hole with the smallest channel capacity from the selection results of the spectrum hole, and the slave user The user accesses the spectrum hole with the smallest channel capacity among the multiple selection results. 8. The system according to claim 6, characterized in that, the system further comprises: a spectrum hole switching judging module, which is used to filter out the spectrum holes in the spectrum hole from the re-selection results of the spectrum holes in the uniform interval calculation module. After the spectral hole in the uniform interval to obtain the screening sub-result of the spectral hole, before sending the screening sub-result to the spectrum hole access module, it is judged whether the screening sub-result is an empty set; if the screening sub-result is If the set is empty, the spectrum hole access module selects the spectrum hole with the smallest channel capacity in the selection results of the spectrum holes, and connects the user to the spectrum hole with the smallest channel capacity in the selection results. ; Otherwise, select the spectrum hole with the smallest channel capacity in the screening sub-results of the spectrum holes by the spectrum hole access module, and access the user to the spectrum hole with the smallest channel capacity in the screening sub-results. 9. The system according to claim 6, wherein the channel capacity calculation module is further used to calculate the channel corresponding to the spectrum hole in combination with frequency factors and propagation environment factors according to the preliminary detection result of the spectrum hole capacity. 10. The system according to claim 6, wherein the uniform interval calculation module is further used to calculate the partial derivative of frequency through the channel capacity corresponding to the spectral hole, or through the channel capacity corresponding to the spectral hole The difference between the capacity and the transmission rate requirement of the slave user is used to calculate the uniform interval where the center frequency of the spectrum hole currently accessed by the slave user is located.

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