CN101610094B - Method for selecting channel and communication system - Google Patents

Abstract

The embodiment of the invention discloses a channel selection method and a communication system. The channel selection method includes: obtaining the interference level of the working subbands of each logical channel; comparing the interference level of the working subbands of each logical channel; selecting a logic with a small interference level of the working subbands channel as the logical channel on which to send newly created beacon periods. The communication system includes: an acquisition unit, configured to acquire the interference level of the working sub-band of each logical channel; a processing unit, configured to compare the magnitude of the interference level acquired by the acquisition unit; a selection unit, configured according to As a result of the comparison, the processing unit selects a logical channel with a small interference level in the working subband as the logical channel for sending the newly created beacon period. The technical solution of the embodiment of the present invention can reduce the interference between the devices of adjacent piconets, and improve the system performance.

Description

Channel selecting method and communication system

Technical field

The present invention relates to communication technical field, be specifically related to a kind of channel selecting method and communication system.

Background technology

Ultra broadband (ultra wideband, UWB) is the key technology that realizes Technology in High-speed WPAN (wireless personal area network, WPAN) multimedia transmission as the new generation of wireless communication technology.The UWB technology mainly contains dual mode at present: Mb-ofdm (multi-band orthogonalfrequency division multiplexing, MB-OFDM) and direct sequence CDMA (direct-sequence code division multiple access, DS-CDMA).As first commercial UWB standard in the world, ECMA-368 standard and ECMA-369 standard have been produced at present based on WiMedia UWB (radio multimedium ultra broadband) platform of MB-OFDM.At present, China is also in the UWB standard of formulating oneself.

For the MB-OFDM-UWB technology, use time-frequency code TFC (Time-Frequency Code) coding to distinguish logic channel, 14 sub-frequency bands are divided into 5 groups, every group comprises three or two frequency ranges, be time-frequency (the Time-frequency Interleaving that interweaves by two types time-frequency codes, TFI) code and fixed frequency interweave (Fixed Frequency Interleaving, FFI) yard, are divided into altogether 30 logic channels.Time-frequency code is a kind of frequency hopping, piconet is Wireless Personal Network (WPAN, Wireless Personal AreaNetwork) basic structural unit, if the time-frequency code that a certain piconet adopts is 123123, represent that then the 1st OFDM symbol sends in frequency range 1, the 2nd OFDM symbol sends in frequency range 2, and the 3rd OFDM symbol sends in frequency range 3, and the 4th OFDM symbol sends in frequency range 1 ... by that analogy.In the ECMA-368 standard, adopt distributed medium access control MAC (Medium AccessControl) agreement.Each equipment will send the beacon of oneself and announce own existence, and the beacon by monitoring miscellaneous equipment is to know existing and moving of miscellaneous equipment.In this standard, adopt the operation between the superframe Mediation Device.Superframe is long to be divided into 256 parts of medium access time slot MAS (MediumAccess Slots) for 65.536ms, and each MAS is 256 μ s.A superframe is made of two parts: beacon period (BP, Beacon Period) and data transfer period (DTP, Data Transmission Period).At BP, beacon frame exchange of management and control information by each equipment sends have then guaranteed sequentially to access wireless medium by BP.

In the prior art, each equipment can be initiated the BP of oneself, has beacon period time started BPST (Beacon Period Start Time) and the BP length (being determined that by the number of devices in its sphere of action regulation has higher limit) of oneself.For fear of adjacent equipment a plurality of overlapping BP are arranged, after a new device power job, before it sends any frame, all will scan the beacon frame of at least one super frame period length.When a super frame period interscan does not detect the beacon frame head, need to create a new BP, detect in addition the beacon frame head, and at the frame check sequence FCS of beacon frame (Frame CheckSequence) when mistake not occurring, attempt adding a piconet, if all piconets all can't add, also to create a new BP this moment.

Wanting newly-built BP when equipment, is to select logic channel according to predefined priority of logical channels, at the new BP of logic channel transmission of this selection.Predefined priority of logical channels is referring to table 1.

Table 1: logic channel is selected priority

As shown in table 1, if belong to battery powered mobile device, power consumption is limited, and for TFI, the priority of logic channel is that logic channel 7 is limit priority, then can preferentially be chosen in the new BP of transmission on the logic channel 7.

In the research and practice process to prior art, the inventor finds that there is following problem in prior art:

It mainly is two kinds that equipment needs the reason of a newly-built BP: do not have other piconet in (1) equipment range of receiving in work; (2) in the equipment range of receiving piconet of working is arranged, but owing to there are not enough resources, equipment can't access.For the first reason, in range of receiving, there is not other MB-OFDM equipment (piconet devices), can not devices illustrated when work, can not be subject to the interference of other MB-OFDM equipment outside the scope; For the second reason, will inevitably there be the interference of other MB-OFDM equipment.Therefore, in the prior art, simply carry out logic channel according to priority and select, might make the interference between the equipment of adjacent piconets very large, affect the performance of system.

Summary of the invention

The technical problem that the embodiment of the invention will solve provides a kind of channel selecting method and communication system, can reduce the interference between the equipment of adjacent piconets, improves systematic function.

For solving the problems of the technologies described above, embodiment provided by the present invention is achieved through the following technical solutions:

The embodiment of the invention provides a kind of channel selecting method, comprising: the interference level that obtains the working sub-band of each logic channel; The size of the interference level of the working sub-band of more described each logic channel; Select the little logic channel of the interference level of described working sub-band as the logic channel that sends the new beacon period that creates.

The embodiment of the invention provides a kind of communication system, comprising: acquiring unit, for the interference level of the working sub-band of obtaining each logic channel; Processing unit is used for the size of the described interference level that more described acquiring unit obtains; Selected cell is used for the comparative result according to described processing unit, selects the little logic channel of the interference level of working sub-band as the logic channel that sends the new beacon period that creates.

Technique scheme can be found out, embodiment of the invention selection of technical scheme logic channel, the interference level of the working sub-band by obtaining each logic channel specifically, the size of the interference level of the working sub-band of more described each logic channel, and then according to comparative result, therefrom select again the little logic channel of the interference level of described working sub-band as the logic channel that sends the new beacon period that creates, so just can overcome the defective that prior art simply selects logic channel to bring according to priority, interference between the equipment of minimizing adjacent piconets improves systematic function.

Description of drawings

Fig. 1 is the embodiment of the invention one channel selecting method flow chart;

Fig. 2 is the embodiment of the invention two channel selecting method flow charts;

Fig. 3 is the particular flow sheet of the embodiment of the invention two steps 202;

Fig. 4 is the embodiment of the invention three channel selecting method flow charts;

Fig. 5 is the embodiment of the invention and the error rate comparative graph of prior art two schemes under the CM1 channel model;

Fig. 6 is the embodiment of the invention and the throughput comparative graph of prior art two schemes under the CM1 channel model;

Fig. 7 is the embodiment of the invention and the error rate comparative graph of prior art two schemes under the CM2 channel model;

Fig. 8 is the embodiment of the invention and the throughput comparative graph of prior art two schemes under the CM2 channel model;

Fig. 9 is the embodiment of the invention and the error rate comparative graph of prior art two schemes under the CM3 channel model;

Figure 10 is the embodiment of the invention and the throughput comparative graph of prior art two schemes under the CM3 channel model;

Figure 11 is the embodiment of the invention and the error rate comparative graph of prior art two schemes under the CM4 channel model;

Figure 12 is the embodiment of the invention and the throughput comparative graph of prior art two schemes under the CM4 channel model;

Figure 13 is embodiment of the invention communication system architecture schematic diagram.

Embodiment

The embodiment of the invention provides a kind of channel selecting method, can reduce the interference between the equipment of adjacent piconets, improves systematic function.

Embodiment of the invention technical scheme mainly is by the interference level of the working sub-band of each logic channel relatively, select the little logic channel of interference level as the logic channel that sends the new beacon period BP that creates, thus the interference between the equipment of minimizing adjacent piconets.

Seeing also Fig. 1, is the embodiment of the invention one channel selecting method flow chart, comprises step:

Step 101, obtain the interference level of the working sub-band of each logic channel;

The interference level that obtains the working sub-band of each logic channel is specially:

In set point number, detect the interference level of the working sub-band of each logic channel by hop period, obtain testing result.Described hop period is 18 OFDM symbol times, and the logic channel number is 7; Perhaps, described hop period is 24 OFDM symbol times, and the logic channel number is 12.

The size of the interference level of the working sub-band of step 102, more described each logic channel;

Specifically the interference level of the working sub-band of described each logic channel carried out logical operation, compare according to operation result, obtain the putting in order of the interference level of the working sub-band of each logic channel.

Step 103, select the little logic channel of the interference level of described working sub-band as the logic channel that sends the new beacon period BP that creates.

Among the embodiment one, select logic channel by above-mentioned steps, can reduce the interference between the equipment of adjacent piconets, improve systematic function.

Following content is selected to be introduced to carry out logic channel under the ECMA-368 standard first.

Seeing also Fig. 2, is the embodiment of the invention two channel selecting method flow charts, comprises step:

Step 201, detect the interference level of the working sub-band of each logic channel by hop period, obtain testing result;

When equipment determines to want newly-built BP, at first the working sub-band of each logic channel is carried out the detection of interference level, in the present embodiment, what the detection of described interference level was used is the detection method of matched filter.Consider the frequency pattern of logic channel, detection is take an OFDM symbol time as unit, the detection order is as follows: 123123213213312312 (this pattern is the frequency pattern of logic channel), be that first symbol time detects No. 1 working sub-band, detect No. 2 working sub-band in second symbol time, by that analogy, once detection need to detect a hop period.That is to say, according to the frequency pattern of logic channel, in a hop period, the interference level in OFDM symbol time of working sub-band detection of each logic channel.Under the ECMA-368 standard, hop period is 18 OFDM symbol times.Consider sequence problem, same detection is carried out repeatedly.In the present embodiment, consider sequential, former and later two OFDM symbols comprise identical with not identical situation, therefore successively carry out 4 times, can carry out continuously also can carrying out again every a period of time, for so that each result who detects is uncorrelated as far as possible in time, detection can be carried out once in the time at each MAS.

Step 202, use testing result are carried out logical operation as input by certain evaluation algorithms, according to operation result, select logic channel;

Each logic channel relatively in, that interference level minimum take the logic channel working sub-band is as target, and for a logic channel, when using evaluation algorithms to carry out logical operation, the interference level minimum in 6 OFDM symbol times of logic channel is as target.

The selection result that step 203, basis obtain sends new BP at selecteed logic channel.

Below step 202 is specifically introduced.

The embodiment of the invention uses gray scale association analysis method as evaluation algorithms, specific practice is as index with the interference level in each OFDM symbol time of logic channel hop period, with 7 logic channels using as alternative, be that each logic channel corresponds to a scheme, thereby the logic channel selection problem when equipment is initiated new BP is converted into typical many Criteria Decision Makings problem, sets up many Criteria Decision Makings model.

Further, in the design process of logic channel selection strategy, consider simultaneously the problem of sequential, static selection strategy is generalized to the Dynamic Multiple Index judgement, thereby farthest reflect the combination property of each scheme, improve the accuracy of judgement.

Seeing also Fig. 3, is the particular flow sheet of the embodiment of the invention two steps 202, comprises step:

301, obtain estimating matrix by the interference level of input and the frequency pattern of logic channel;

Detect the interference level of the working sub-band that obtains each logic channel by step 201 after, testing result is consisted of a matrix:

$G^t={\left(g_{\mathrm{cj}}^t\right)}_{3\×6}=\left(\begin{array}{ccccc}{g}_{11}^t& \·& \·& \·& g_{16}^t\\ \·& \·& & & \·\\ \·& & \·& & \·\\ \·& & & \·& \·\\ g_{31}^t& \·& \·& \·& g_{36}^t\end{array}\right)$

Wherein 1≤c≤3 represent frequency point number, j OFDM symbol in 1≤j≤hop period of 6 expressions, the result that 1≤t≤4 expressions detect for the t time, so g _Cj ^tBe exactly in the t time is detected in j OFDM symbol time the interference level on the c work song frequency range big or small.Then, according to matrix G ^t, and in conjunction with the frequency pattern of logic channel, can obtain G ^tTesting result in the t time is detected is matrix A ^t, matrix A ^tIn detecting as the t time, to estimate matrix for one of the interference level size that each logic channel is subject in each OFDM symbol time, specific as follows:

$A^t={\left(a_{\mathrm{ij}}^t\right)}_{7\×6}=\left(\begin{array}{ccccc}{a}_{11}^t& \·& \·& \·& a_{16}^t\\ \·& \·& & & \·\\ \·& & \·& & \·\\ \·& & & \·& \·\\ a_{71}^t& \·& \·& \·& a_{76}^t\end{array}\right)$

Wherein 1≤i≤7 represent the sequence number of alternative logic channel, j OFDM symbol in 1≤j≤hop period of 6 expressions, the result that 1≤t≤4 expressions detect for the t time, so a _Ij ^tBe exactly in the t time is detected, if when using the i logic channel, the interference level size that in j OFDM symbol time, is subject to.Owing to detected four times, can obtain four different evaluation matrixes, with they input matrixes as following algorithm.

Step 302, carry out standardization processing to estimating matrix;

Because interference level belongs to cost type index, and is namely more little more excellent, so pass through formula (1) to matrix A ^tCarry out standardization processing.

$b_{\mathrm{ij}}^t=\frac{\min \left\{a_{\mathrm{ij}}^t\right|1\≤i\≤n\}}{a_{\mathrm{ij}}^t},i=\mathrm{1,2,3},\·\·\·,n$ Formula (1)

The decision matrix that can standardize thus is as follows:

$B^t={\left(b_{\mathrm{ij}}^t\right)}_{7\×6}=\left(\begin{array}{ccccc}{b}_{11}^t& \·& \·& \·& b_{16}^t\\ \·& \·& & & \·\\ \·& & \·& & \·\\ \·& & & \·& \·\\ b_{71}^t& \·& \·& \·& b_{76}^t\end{array}\right)$

Step 303, by the standardization decision matrix, calculate the weight between each index in the standardization decision matrix;

Calculate the weight between each index in the standardization decision matrix, in fact the weight of each numerical value in the compute matrix namely.In many index judgements, determine that the method for index weights mainly contains subjective enabling legislation and objective weighted model.Objective weighted model is adopted in the impact that the embodiment of the invention is brought artificial subjective factor for fear of subjective enabling legislation, according to the information entropy theory in the Analysis of Policy Making, determines the weight of evaluation index with Information Entropy.

In embodiments of the present invention, adopt comentropy $H\left(x\right)=-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}p\left(x_i\right)*\ln P\left(x_i\right)$ As the tolerance of the unordered degree of system, information is the tolerance of system order degree, and both absolute values equate, opposite in sign.In the multiple target judgement, the property value intensity of variation of a certain index is larger, and comentropy is less, and the amount of information that this index provides is larger, and the weight of this index also should be larger; Otherwise the property value intensity of variation of a certain index is less, and comentropy is larger, and the amount of information that this index provides is less, and the weight of this index also should be less.So, can according to the degree of variation of indices property value, utilize comentropy to calculate the weight of each index.

Below be computational process:

1) entropy of j index of calculating;

$e_j^t=-\underset{i=1}{\overset{7}{\mathrm{\Σ}}}{b}_{\mathrm{ij}}^t*\ln b_{\mathrm{ij}}^i,j=\mathrm{1,2},\·\·\·,6$

2) definition otherness coefficient;

For j index, the otherness of property value is less, then e _j ^tLarger; When desired value all equates, $e_j^t=e_{\max }^t=1,$ This moment, property value was like water off a duck's back for the comparison of scheme; When the desired value of each scheme differs larger, e _j ^tLess, this index is larger for the scheme role.Therefore, definition otherness coefficient:

$g_j^t=1-e_j^t,j=\mathrm{1,2},\·\·\·,6$

3) determine index weights.

Because to index without any preference, so j index weights is:

$w_j^t=\frac{g_j^t}{\underset{j=1}{\overset{6}{\mathrm{\Σ}}}{g}_j^t},j=\mathrm{1,2},\·\·\·,6$

Step 304, by standardization decision matrix and index weights, calculate the grey correlation vector of local optimum judgement reference vector and the poorest local judgement reference vector of 7 schemes;

In the design process of the logic selection strategy of intensity-based association, it is excellent, poor with reference to scheme and feasible program incidence coefficient and the degree of association to excellent, poor scheme at first to define, purpose is them as the standard of weighing other feasible schemes to weigh the excellent poor of each scheme, so just can solve to a certain extent and only consider in the optimum reference vector situation problem that when incidence coefficient differs very little under this parameter, is difficult to make a strategic decision.

According to the standardization decision matrix, carry out as giving a definition:

Definition 1: vector $Q_{\max }^t=(h_1^t,h_2^t,h_3^t,h_4^t),h_k^t=\underset{1\&le;i\&le;7}{\mathrm{<figure-callout\; id="1"\; label="max"\; filenames="S2008101269679E00052.png,S2008101269679E00062.png"\; state="\{\{state\}\}">max</figure-callout>}}{b}_{\mathrm{ik}}^t$ Be sequential T _tLocal optimum judgement reference vector.

Definition 2: vector $Q_{\min }^t=(s_1^t,s_2^t,s_3^t,s_4^t),s_k^t=\underset{1\&le;i\&le;7}{\mathrm{<figure-callout\; id="1"\; label="min"\; filenames="S2008101269679E00052.png,S2008101269679E00062.png"\; state="\{\{state\}\}">min</figure-callout>}}{b}_{\mathrm{ik}}^t$ Be sequential T _tThe poorest judgement reference vector in part.

Because the paradox between multiobject judgement target usually has: $Q_{\min }^t\&NotEqual;b_{\mathrm{ij}}^t,j=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,6$ Or $Q_{\max }^t\&NotEqual;b_{\mathrm{ij}}^t,j=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,6.$

Calculate T _iThe grey relational grade of standardization decision matrix and its local optimum judgement reference vector is under the sequential:

$f_{\mathrm{ij}}^t=\frac{\underset{i}{\min }\underset{j}{\min }|h_j^t-b_{\mathrm{ij}}^t|+\mathrm{\&rho;}\underset{i}{\max }\underset{j}{\max }|h_j^t-b_{\mathrm{ij}}^t|}{|h_j^t-b_{\mathrm{ij}}^t|+\mathrm{\&rho;}\underset{i}{\max }\underset{j}{\max }|h_j^t-b_{\mathrm{ij}}^t|}$

Wherein ρ is resolution ratio, and ρ ∈ [0,1] generally gets ρ=0.5.

By 7*6 f _Ij ^tStructure grey correlation judgment matrix F ^tFor:

$F^t={\left(f_{\mathrm{ij}}^t\right)}_{7\&times;6}=\left(\begin{array}{ccccc}{f}_{11}^t& \&CenterDot;& \&CenterDot;& \&CenterDot;& f_{14}^t\\ \&CenterDot;& \&CenterDot;& & & \&CenterDot;\\ \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& & & \&CenterDot;& \&CenterDot;\\ f_{121}^t& \&CenterDot;& \&CenterDot;& \&CenterDot;& f_{124}^t\end{array}\right)$

In conjunction with index weights and grey correlation judgment matrix, can calculate T _iSequential scheme i (i=1,2 ..., 7) effect and the grey relational grade of its local optimum judgement reference vector be:

${\mathrm{\&chi;}}_i^t=\underset{j=1}{\overset{6}{\mathrm{\&Sigma;}}}{w}_j^t{f}_{\mathrm{ij}}^i,j=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,6,i=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,7$

Then the grey relational grade vector of all 7 schemes and local optimum judgement reference vector is: (χ _i ^t) ^T, i=1,2 ..., 7

In like manner, can calculate T _iSequential scheme i (i=1,2 ..., 7) effect and the grey relational grade of its poorest judgement reference vector in part be ψ _i ^t(i=1,2 ..., 7), then all 7 schemes with the grey relational grade vector of the poorest local judgement reference vector are:

(ψ _i ^t) ^T，i＝1，2，…，7。

Step 305, by the grey relational grade vector of the poorest judgement reference vector in grey relational grade vector sum part of local optimum judgement reference vector, it is vectorial to calculate the poorest judgement of total optimization judgement vector sum integral body;

The grey relational grade vector of the local optimum judgement reference vector of comprehensive 7 schemes in 4 sequential obtains the total optimization incidence matrices:

$X=\left(\begin{array}{ccccc}{\mathrm{\&chi;}}_1^1& \&CenterDot;& \&CenterDot;& \&CenterDot;& {\mathrm{\&chi;}}_1^4\\ \&CenterDot;& \&CenterDot;& & & \&CenterDot;\\ \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& & & \&CenterDot;& \&CenterDot;\\ {\mathrm{\&chi;}}_7^1& \&CenterDot;& \&CenterDot;& \&CenterDot;& {\mathrm{\&chi;}}_7^4\end{array}\right)$

Again this matrix is inputted as algorithm, by the cycle calculations of step 301-303, obtain scheme i (i=1,2 ..., 7) interrelating effect be χ with whole desirable optimum grey relational grade _i(i=1,2 ..., 7), further can get total optimization judgement vector and be R=(χ ₁, χ ₂..., χ ₇) ^T

In like manner, can get the most bad whole incidence matrices:

$E_{\mathrm{\&beta;}}=\left(\begin{array}{ccccc}{\mathrm{\&psi;}}_1^1& \&CenterDot;& \&CenterDot;& \&CenterDot;& {\mathrm{\&psi;}}_1^4\\ \&CenterDot;& \&CenterDot;& & & \&CenterDot;\\ \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& & & \&CenterDot;& \&CenterDot;\\ {\mathrm{\&psi;}}_7^1& \&CenterDot;& \&CenterDot;& \&CenterDot;& {\mathrm{\&psi;}}_7^4\end{array}\right)$

Thereby obtain the poorest judgement vector of integral body: C=(ψ ₁, ψ ₂..., ψ ₇) ^T

Step 306, vectorial by the poorest judgement of total optimization judgement vector sum integral body obtains the ordering vector of decision scheme.

According to the poorest judgement vector of total optimization judgement vector sum integral body, the ordering vector that can obtain decision scheme is P=(p ₁, p ₂..., p ₇) ^T, 0≤p wherein _i≤ 1.Scheme i is with the expectation Probability p _iBe subordinated to excellent scheme, take desired value as 1-p _iBe subordinated to bad scheme.So, just can determine which scheme is optimum according to ordering vector, determine that namely which logic channel is optimum.

Further, the final goal of considering algorithm is that the excellent scheme of some schemes distance is nearer the time and away from bad scheme, thereby when making other schemes away from excellent scheme near bad scheme, this is equivalent to and makes decision scheme neither be subordinated to the desired value minimum that excellent scheme is not subordinated to again bad scheme, by can more obviously distinguishing various alternatives like this, avoid occurring ambiguous judgement predicament.Therefore, can propose target function f (x) according to the least square method of classics, set up comprehensive optimal decision model:

$\max f({\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008101269679E00052.png,S2008101269679E00062.png"\; state="\{\{state\}\}">p</figure-callout>}}_1,p_2,\&CenterDot;\&CenterDot;\&CenterDot;,p_7)=\max \underset{i=1}{\overset{7}{\mathrm{\&Sigma;}}}\{{\left(p_i{\mathrm{\&chi;}}_i\right)}^2+{\left[(1-p_i){\mathrm{\&psi;}}_i\right]}^2\}$

In order conveniently to find the solution, above-mentioned formula is carried out inverse transformation, can get

$\min [-f({\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="S2008101269679E00052.png,S2008101269679E00062.png"\; state="\{\{state\}\}">p</figure-callout>}}_1,p_2,\&CenterDot;\&CenterDot;\&CenterDot;,p_7)]=\min \underset{i=1}{\overset{7}{\mathrm{\&Sigma;}}}\{{\left[(1-p_i){\mathrm{\&chi;}}_i\right]}^2+{\left(p_i{\mathrm{\&psi;}}_i\right)}^2\}$

Optimal solution vector P=(p for solving system ₁, p ₂..., p _n) ^T, scheme i is with the expectation Probability p _iThe correlation degree that is subordinated to excellent scheme is maximum, order $\frac{\mathrm{\&delta;f}}{\mathrm{\&delta;}{p}_i}=0,$ Can get $p_i=\frac{{\mathrm{\&chi;}}_i^2}{{\mathrm{\&chi;}}_i^2+{\mathrm{\&psi;}}_i^2}.$

Obviously, this moment p _iResult of calculation is larger, and scheme i is just more near total optimization judgement vector, more away from the poorest judgement vector of integral body.

According to result of calculation, can again determine again Priority Vector P=(p ₁, p ₂..., p _n) ^T, p _iArranged sequentially by from big to small so can more accurate selection scheme, i.e. more accurate selection logic channel.

Need to prove that in the above-mentioned steps, it is for example makes things convenient for subsequent calculations that step 302 pair evaluation matrix carries out standardization processing, also can not carry out standardization processing.In addition, adopting gray scale association analysis method also is an example as evaluation algorithms, just in order more easily the interference level of the working sub-band of each logic channel of detecting to be compared by this logical operation, thereby select the little logic channel of interference level, it also is passable adopting other logical operations, as long as can compare the size of interference level, its principle is similar.

Can find, embodiment two technical schemes, under the ECMA-368 standard, by adopting gray scale association analysis method as evaluation algorithms, can compare accurately the size of interference level of the working sub-band of each logic channel, thereby can select the little logic channel of interference level to send newly-built BP, with the interference between the equipment that reduces adjacent piconets, improve systematic function.

Embodiment two selects to be introduced to carry out logic channel under the ECMA-368 standard, and for the UWB standard that China proposes, the technical scheme of the embodiment of the invention is applicable equally.

Seeing also Fig. 4, is the embodiment of the invention three channel selecting method flow charts, comprises step:

Step 401, detect the interference level of the working sub-band of each logic channel by hop period, obtain testing result;

When equipment determines to want newly-built BP, at first the working sub-band of each logic channel is carried out the detection of interference level, in the present embodiment, what the detection of described interference level was used is the detection method of matched filter.Consider the frequency pattern of logic channel frequency hopping, detect take an OFDM symbol time as unit, in first carrier receiver place detection sequentially be: 345634653546356436453654 (this pattern is the frequency pattern of logic channel); Second carrier receiver place detection sequentially be: 789107810979810791087108971098.That is to say that at first carrier receiver place, first symbol time detects No. 3 working sub-band, detect No. 4 working sub-band in second symbol time; At second carrier receiver place, first symbol time detects No. 7 working sub-band, detects No. 8 working sub-band in second symbol time, and by that analogy, detection once need to detect a hop period.That is to say, according to the frequency pattern of logic channel, in a hop period, the interference level in OFDM symbol time of working sub-band detection of each logic channel.Under the China UWB standard, hop period is 24 OFDM symbol times.Consider sequence problem, same detection is carried out repeatedly.In the present embodiment, consider sequential, former and later two OFDM symbols comprise identical with not identical situation, therefore successively carry out 4 times, can carry out continuously also can carrying out again every a period of time, for so that each result who detects is uncorrelated as far as possible in time, detection can be carried out once in the time at each MAS.

Step 402, use testing result are carried out logical operation as input by certain evaluation algorithms, according to operation result, select logic channel;

Each logic channel relatively in, that interference level minimum take the logic channel working sub-band is as target, and for a logic channel, when using evaluation algorithms to carry out logical operation, the interference level minimum in 4 OFDM symbol times of logic channel is as target.

The selection result that step 403, basis obtain sends new BP at selecteed logic channel.

For step 402, also be to use gray scale association analysis method as evaluation algorithms, specific practice is as index with the interference level in each OFDM symbol time of logic channel hop period of Chinese UWB standard, with 12 logic channels using as alternative, be that each logic channel corresponds to a scheme, thereby the logic channel selection problem when equipment is initiated new BP is converted into typical many Criteria Decision Makings problem, sets up many Criteria Decision Makings model.

Further, in the design process of logic channel selection strategy, consider simultaneously the problem of sequential, static selection strategy is generalized to the Dynamic Multiple Index judgement, thereby farthest reflect the combination property of each scheme, improve the accuracy of judgement.

Detailed process as for step 402 may further comprise the steps:

Step 501, by the input interference level and the frequency pattern of logic channel obtain estimating matrix;

Step 502, carry out standardization processing to estimating matrix;

Step 503, by the standardization decision matrix, calculate the weight between each index in the standardization decision matrix;

Step 504, by standardization decision matrix and index weights, calculate the grey correlation vector of local optimum judgement reference vector and the poorest local judgement reference vector of 12 schemes;

Step 505, by the grey relational grade vector of the poorest judgement reference vector in grey relational grade vector sum part of local optimum judgement reference vector, it is vectorial to calculate the poorest judgement of total optimization judgement vector sum integral body.

Step 506, vectorial by the poorest judgement of total optimization judgement vector sum integral body obtains the ordering vector of decision scheme.

Concrete steps in above-mentioned steps and the example one in the step 202 are similar, here repeated description no longer.

Can find, embodiment three technical schemes, under Chinese UWB standard, by adopting gray scale association analysis method as evaluation algorithms, can compare accurately the size of interference level of the working sub-band of each logic channel, thereby can select the little logic channel of interference level to send newly-built BP, with the interference between the equipment that reduces adjacent piconets, improve systematic function.

In order better to embody the beneficial effect that embodiment of the invention technical scheme and prior art scheme have, embodiment of the invention technical scheme and prior art scheme are carried out emulation testing.

Test environment is: suppose in the area of a 20m * 20m that by 3 piconets in work, the radius of clean-up of each piconet is 10m, the logic channel of work at random but not identical needs the equipment of newly-built BP to be in outside 3 piconet scopes.

Superframe structure for ECMA-368 is simplified, just considered distributed reservation protocol DR P (Distributed Reservation Protocol) part, the sending and receiving node is constant in each MAS of piconet, and each MAS of sending and receiving node changes once the worst case of consideration 100% work.The transmitting power of each piconet devices is the upper limit-41.3dBm/Mhz.Only consider in addition the situation when throughput is 160Mbps.

Four kinds of channels that provide for IEEE (model of CM1～CM4), simulation result such as Fig. 5-shown in Figure 12.

Fig. 5 is the embodiment of the invention and the prior art two schemes error rate comparative graph under the CM1 channel model; Fig. 7 is the embodiment of the invention and the prior art two schemes error rate comparative graph under the CM2 channel model; Fig. 9 is the embodiment of the invention and the prior art two schemes error rate comparative graph under the CM3 channel model; Figure 11 is the embodiment of the invention and the prior art two schemes error rate comparative graph under the CM4 channel model.Among these four figure, the corresponding prior art scheme of top curve, the corresponding embodiment of the invention scheme of following curve.Can find that the embodiment of the invention scheme error rate is little.

Fig. 6 is the embodiment of the invention and the prior art two schemes throughput comparative graph under the CM1 channel model; Fig. 8 is the embodiment of the invention and the prior art two schemes throughput comparative graph under the CM2 channel model; Figure 10 is the embodiment of the invention and the prior art two schemes throughput comparative graph under the CM3 channel model; Figure 12 is the embodiment of the invention and the prior art two schemes throughput comparative graph under the CM4 channel model.Among these four figure, the corresponding prior art scheme of following curve, the corresponding embodiment of the invention scheme of top curve.Can find that embodiment of the invention scheme throughput of system is high.

Generally speaking, can find out according to simulation result that under various channel models, embodiment of the invention technical scheme has the less error rate and the throughput of Geng Gao than prior art scheme.

Need to prove, because multi-band OFDM UWB technology is based on the UWB scheme that the OFDM technology proposes, therefore adopt the communication system of the technology of OFDM for some, such as the 4G system, all can adopt embodiment of the invention technical scheme when relating to when switch channel selection and residential quarter, its principle is similar.

One of ordinary skill in the art will appreciate that all or part of step that realizes in above-described embodiment method is to come the relevant hardware of instruction to finish by program, described program can be stored in a kind of computer-readable recording medium, described storage medium can be read-only memory, disk or CD etc.

The introduction that foregoing is detailed embodiment of the invention channel selecting method, corresponding, the embodiment of the invention provides a kind of communication system.

Seeing also Figure 13, is embodiment of the invention communication system architecture schematic diagram.

As shown in figure 13, communication system comprises: acquiring unit 131, processing unit 132, selected cell 133.

Acquiring unit 131 is for the interference level of the working sub-band of obtaining each logic channel.

Processing unit 132 is used for the size of the described interference level that acquiring unit 131 relatively obtains.

Selected cell 133 is used for the comparative result according to described processing unit 132, selects the little logic channel of the interference level of working sub-band as the logic channel that sends the new beacon period BP that creates.

The processing unit 132 of communication system further comprises: operation processing unit 1321, comparing unit 1322.

Operation processing unit 1321, the described interference level that is used for described acquiring unit 131 is obtained carries out logical operation.

Comparing unit 1322 is used for comparing according to the logic operation result of described operation processing unit 1321, obtains putting in order of described interference level that described acquiring unit 131 obtains.

Described operation processing unit 1321 further comprises: setting unit 13211, weight unit 13212, the first associative cell 13213, the second associative cell 13214.

Setting unit 13211, for the described interference level of described each logic channel that obtains according to described acquiring unit 131, and the frequency pattern of described each logic channel, obtain the first matrix.

Weight unit 13212 is used to the numerical value configure weights in described the first matrix.Can according to the information entropy theory in the Analysis of Policy Making, determine that with Information Entropy evaluation index is the weight of the numerical value in the first matrix.

The first associative cell 13213 is used for according to described the first matrix and described weight, determines that the described interference level of described each logic channel is vectorial with the grey relational grade of each local optimum judgement reference vector and each the poorest judgement reference vector in part respectively.Communication system is to use gray scale association analysis method as evaluation algorithms, and therefore the correlation principle according to this algorithm calculates relevant grey relational grade vector.

The second associative cell 13214, be used for the described grey relational grade vector of comprehensive described each local optimum judgement reference vector and the described grey relational grade vector of described each the poorest judgement reference vector in part and carry out computing, obtain the poorest judgement vector of total optimization judgement vector sum integral body.

Described comparing unit 1322 according to the poorest judgement vector of the described integral body of described total optimization judgement vector sum that described the second associative cell 13214 obtains, obtains the ordering vector of each logic channel.So, just can determine which scheme is optimum according to ordering vector, determine that namely which logic channel is optimum.

Described operation processing unit 1321 further comprises: standardization processing unit 13215.

Standardization processing unit 13215, described the first matrix that is used for described setting unit 13211 is obtained carries out standardization processing; Described weight unit 13212 is to be the numerical value configure weights in described the first matrix after the standardization processing.Described the first associative cell 13213 is according to described the first matrix and described weight after the standardization processing, determines the grey relational grade vector.

The processing unit 132 of communication system further comprises: optimize unit 1323.

Optimize unit 1323, be used for according to least square method the described ordering vector that described comparing unit 1322 obtains being carried out computing, redefine ordering vector according to the result of described computing.

The acquiring unit 131 of communication system further comprises: detecting unit 1311, receiving element 1312.

Detecting unit 1311 is used for the frequency pattern according to described each logic channel, and in hop period, the interference level of a working sub-band OFDM symbol of detection in the time at described each logic channel obtains testing result.Consider sequence problem, same detection is undertaken repeatedly by detecting unit 1311.In the present embodiment, consider sequential, former and later two OFDM symbols comprise identical with not identical situation, so detecting unit 1311 successively carries out 4 detections.Receiving element 1312 is for the testing result that receives described detecting unit 1311.

Described hop period when described detecting unit 1311 detects is 18 OFDM symbol times, and the logic channel number is 7, and this situation is applicable to the ECMA-368 standard; Perhaps, described hop period is 24 OFDM symbol times, and the logic channel number is 12, and this situation is applicable to the UWB standard that China proposes.

In sum, embodiment of the invention selection of technical scheme logic channel, the interference level of the working sub-band by obtaining each logic channel specifically, the size of the interference level of the working sub-band of more described each logic channel, and then according to comparative result, therefrom select again the little logic channel of the interference level of described working sub-band as the logic channel that sends the new beacon period BP that creates, so just can overcome the defective that prior art simply selects logic channel to bring according to priority, interference between the equipment of minimizing adjacent piconets improves systematic function.

Further, embodiment of the invention technical scheme is by using gray scale association analysis method as evaluation algorithms, the size of the interference level of the working sub-band of more described each logic channel of computing by this algorithm, therefore more accurate, thereby select also more accurate.

Further, embodiment of the invention technical scheme goes for the ECMA-368 standard, also goes for the UWB standard that China proposes, applying flexible.

The embodiment of the invention only take " described hop period as 18 OFDM symbol times, logic channel number be 7; Perhaps, described hop period is 24 OFDM symbol times, the logic channel number is 12 " both of these case is that example is illustrated; easily full of beard and be; when described hop period and logic channel number adopted other values, the channel selecting method that the embodiment of the invention discloses and communication system were applicable equally.

More than a kind of channel selecting method and communication system that the embodiment of the invention is provided be described in detail, used specific case herein principle of the present invention and execution mode are set forth, the explanation of above embodiment just is used for helping to understand method of the present invention and core concept thereof; Simultaneously, for one of ordinary skill in the art, according to thought of the present invention, all will change in specific embodiments and applications, in sum, this description should not be construed as limitation of the present invention.

Claims (10)

1. A channel selection method, characterized in that, comprising: Obtaining the interference level of the working subband of each logical channel; Comparing the magnitude of the interference level of the working subbands of the logical channels; Selecting a logical channel with a small interference level in the working subband as the logical channel for sending the newly created beacon period; The size of the interference level of the working sub-band of the described comparison of each logical channel is specifically: Obtain the first matrix according to the interference level of the working subband of each logical channel and the frequency hopping pattern of the logical channel; configuring weights for values in the first matrix; According to the first matrix and the weight, determine the gray correlation degree vectors between the interference level of the working subband of each logical channel and each local optimal decision reference vector and each local worst decision reference vector; Combining the gray correlation degree vectors of each local optimal judgment reference vector and the gray correlation degree vectors of each local worst judgment reference vector to obtain the overall optimal judgment vector and the overall worst judgment vector; According to the overall optimal decision vector and the overall worst decision vector, a ranking vector of each logical channel is obtained. 2. The channel selection method according to claim 1, characterized in that: After obtaining the first matrix according to the interference level of the working subband of each logical channel and the frequency hopping pattern of the logical channel, further include: Perform normalization processing on the first matrix, and then enter the steps of configuring weights and determining gray correlation degree vectors. 3. The channel selection method according to claim 1, characterized in that: After obtaining the sorting vector of each logical channel, it further includes: The sorting vector is operated according to the least square method, and the sorting vector is re-determined according to the operation result. 4. The channel selection method according to any one of claims 1 to 3, characterized in that: The interference level of the working sub-band of each logical channel is specifically obtained as follows: According to the frequency hopping pattern of the logical channel, within the frequency hopping period, the interference level within one OFDM symbol time is detected in the working subband of each logical channel, and the detection result is obtained. 5. The channel selection method according to claim 4, characterized in that: According to the frequency hopping pattern of the logical channel, within the frequency hopping period, the step of detecting the interference level within one OFDM symbol time in the working subband of each logical channel and obtaining the detection result is performed multiple times. 6. The channel selection method according to claim 4, characterized in that: The frequency hopping period is 18 OFDM symbol times, and the number of logical channels is 7; or, the frequency hopping period is 24 OFDM symbol times, and the number of logical channels is 12. 7. A communication system, characterized in that it comprises: an acquisition unit, configured to acquire the interference level of the working subband of each logical channel; a processing unit, configured to compare the magnitude of the interference level obtained by the obtaining unit; A selection unit, configured to select a logical channel with a small interference level in the working subband as the logical channel for sending the newly created beacon period according to the comparison result of the processing unit; The processing unit further includes: an operation processing unit, configured to perform logic operations on the interference level acquired by the acquisition unit; a comparison unit, configured to compare according to the logical operation results of the operation processing unit, and obtain the arrangement order of the magnitudes of the interference levels acquired by the acquisition unit; The operation processing unit further includes: a setting unit, configured to obtain a first matrix according to the interference level of each logical channel obtained by the obtaining unit and the frequency hopping pattern of each logical channel; a weight unit, configured to configure weights for the values in the first matrix; A first associating unit, configured to determine gray associations between the interference levels of the logical channels and the locally optimal decision reference vectors and the local worst decision reference vectors, respectively, according to the first matrix and the weights degree vector; The second association unit is configured to synthesize the gray correlation degree vectors of the local optimal decision reference vectors and the gray correlation degree vectors of the local worst decision reference vectors to obtain an overall optimal decision vector and the overall worst decision vector; The comparing unit obtains a ranking vector of each logical channel according to the overall optimal decision vector and the overall worst decision vector obtained by the second associating unit. 8. The communication system according to claim 7, wherein the operation processing unit further comprises: A normalization processing unit, configured to perform normalization processing on the first matrix obtained by the setting unit; the weight unit configures weights for the values in the first matrix after normalization processing; The first associating unit determines a gray relational degree vector according to the normalized first matrix and the weight. 9. The communication system according to claim 7, wherein the processing unit further comprises: An optimization unit is configured to perform an operation on the sorting vector obtained by the comparison unit according to the least square method, and re-determine the sorting vector according to the result of the operation. 10. The communication system according to claim 7, wherein the acquiring unit further comprises: The detection unit is configured to detect the interference level within one OFDM symbol time in the working subband of each logical channel within the frequency hopping period according to the frequency hopping pattern of each logical channel, and obtain the detection result.

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