CN101296139A - Frequency spectrum cooperation method of dynamic frequency hopping wireless area network - Google Patents

Abstract

The invention discloses a spectrum cooperation method in a dynamic frequency hopping wireless regional area network, which comprises the steps that: all CPEs in the WRAN carry out spectrum detection and feed related idle channel information back to a respective control base station; spectrum resource distribution of the WRAN system under the state of spectrum collision is determined by high priority WRANs. The spectrum cooperation method of the invention is applied to solving the problem of spectrum collision among all overlapping WRANs based on dynamic frequency hopping, thereby effectively ensuring that all WRAN systems, when ensure respective QoS, effectively avoid serious problems of non-realization or relatively long delay of wireless access, etc. of adjacent WRANs caused by the shortage of free idle channels. Therefore, the communication quality and reliability in the coverage scope of the whole WRAN area are improved effectively by the same operator when integrating the whole spectrum resources.

Description

Frequency spectrum cooperation method in the dynamic frequency hopping wireless area network

Technical field

The present invention relates to field of wireless communications systems, particularly the frequency spectrum cooperation method in the dynamic frequency hopping wireless area network based on cognitive radio.

Background technology

In present communication protocols such as IEEE802.22, how regulation and explanation do not utilize effective solution of method of frequency spectrum cooperation to collide more than or equal to the frequency spectrum between the WRAN system of two crossovers.

In the WRAN system of utilization cognitive radio technology, how making full use of limited free empty frequency range, to carry out regional access communications be one of research focus of the current wireless communications field.

Usually, when (In-band) frequency spectrum was detected in each client device in the WRAN system (CPE:Consumer PremiseEquipment) is with, this access network need be sacrificed very long call duration time and is used for the operating position detection that quiet period (Quiet period) is carried out the mandate validated user in the corresponding band.

A kind of WRAN system hops working method based on dynamic frequency hopping is provided in the above-mentioned agreement, thus this structure effectively utilize the enterprising line period frequency hopping of different idle channels shortened greatly be used to in the silence period of frequency spectrum detecting.Fig. 1 example WRAN1 system 104 and WRAN2 system 105 between CHA channel 101 and CHB channel 102 and CHC channel 103, carry out the schematic diagram of flexible frequency hopping.As can be seen from the figure, in first cycle of CHA channel 101, WRAN1 system 104 works in this available frequency band, second runtime, WRAN1 system 104 frequency hoppings communicate to idle CHB channel 102, in the 3rd run duration, WRAN system 104 skips to idle channel CHB103 again.Similarly, for WRAN2 system 105, it jumps to CHA channel 101 and CHB channel 102 by CHC channel 103 respectively in proper order in three runtimes.Thereby guarantee that not only WRAN1 system 104 and WRAN system 2105 can normally work in idle channel incessantly, make also simultaneously each CPE can whether the free time be detected to this channel in the quiet period of each channel.

Fig. 2 has provided the operation chart of WRAN201 in initial spectrum is detected 202 stages and two runtimes 203 and 204.At first, each CPE in the WRAN carries out initial spectrum detecting 202, finds the idle frequency range CHA and the entry-into-force time 205 of institute of this system energy operate as normal; Then, at second period, WRAN skips to CHA and sends data and simultaneously channel CH ([0, A-n], [A+n, N]) is carried out frequency spectrum detecting 203, the entry-into-force time 206 that draws CHB; Next, in the 3rd cycle, WRAN skips to CHB and simultaneously channel CH ([0, B-n], [B+n, N]) is carried out frequency spectrum detecting 204.N is whole channel number to be detected, and n is the protection interval width.

But how solving based on the frequency spectrum collision problem between a plurality of WRAN system of dynamic frequency hopping is one of present research focus.A kind of comparatively general solution be peripherad other WRAN of WRAN1 control centre of at first detecting idle channel CHA send signaling state its to this channel occupy in advance and monitor simultaneously from around the statement broadcasting of other WRAN.Other statements occupy the broadcast message of CHA in advance or the claim information of other system is later than WRAN1 if do not have, and then WRAN1 will be in ensuing cycle frequency hopping to CHA.Therefore, when utilizing this scheme of avoiding based on collision to solve the frequency spectrum conflict, suppose appearance scene as shown in Figure 3 in the WRAN system:

In first cycle, WRAN1 system 301 frequency spectrums detect the CHA entry-into-force time 303, WRAN2 system 302 frequency spectrums detect the CHD entry-into-force time and respectively at the second period frequency hopping to CHA and CHD; In second period, following two kinds of situations take place:

(1) all only to detect CHB be idle channel for WRAN1 system 301 and WRAN2 system 302, but have the different entry-into-force times, is respectively CHB entry-into-force time 305 and CHB entry-into-force time 306;

(2) WRAN1 system 301 only detects idle channel CHB, and the WRAN2 system detects idle channel CHB and CHC simultaneously.But the entry-into-force time of CHC surpasses the maximum delay restriction that system can bear.

Obviously, avoid solution can't ideally solve frequency spectrum collision problem under above-mentioned two kinds of situations based on the collision of competition mechanism.

Summary of the invention

The object of the present invention is to provide a mode of utilizing the frequency spectrum cooperation to solve the method for frequency spectrum conflict between the WRAN system of a plurality of crossovers, thereby make the WRAN system that respectively is in free frequency range operate more efficiently.

For achieving the above object, the frequency spectrum cooperation method in a kind of dynamic frequency hopping wireless area network comprises step:

CPE among all WRAN carries out frequency spectrum detecting and the relevant free channel information control base station extremely separately of feedback;

Be in the frequency spectrum resource distribution of the WRAN system of frequency spectrum collision status by the WRAN decision of high priority.

Adopt the frequency spectrum cooperation method among the present invention to solve, thereby guaranteed effectively that each WRAN system has effectively avoided adjacent WRAN when guaranteeing separately QoS because the wireless access that the shortage of free idle channel is brought can not be realized or delay time serious problems such as bigger based on the frequency spectrum collision problem between each crossover WRAN of dynamic frequency hopping.Thereby improved same operator effectively and improved communication quality and reliability in the coverage of whole WRAN zone effectively integrating frequency spectrum resource.

Description of drawings

Fig. 1 shows the dynamic frequency hopping schematic diagram of many WRAN system;

Fig. 2 shows dynamic frequency hopping operation schematic diagram in the WRAN system;

Fig. 3 shows that the frequency spectrum of two crossover WRAN systems collides schematic diagram;

Fig. 4 shows based on crossover WRAN system configuration of the present invention;

Fig. 5 shows the subchannel partitioning algorithm that adopts frequency spectrum cooperation method;

Fig. 6 shows based on system of the present invention operational flow diagram;

Fig. 7 shows based on the control signaling between the two crossover WRAN base stations of the present invention.

Embodiment

Among Fig. 4, there be the radio area network WRAN-A401 and the WRAN-B402 of two crossovers.At this moment, WRAN-A401 carries out the frequency spectrum detecting and obtains the frequency hopping target frequency bands that the CHB channel can be used as its following one-period; In addition, WRAN-B402 also frequency spectrum detect the frequency hopping target frequency bands that CHB can be used as its following one-period.This time-frequency spectrum conflict betides between WRAN-A401 and the WRAN-B402.

Therefore, thus core concept of the present invention is to realize that by the Signalling exchange between the control centre of crossover WRAN two radio area networks share idle frequency range CHB.Wherein, WRAN-A401 occupies frequency range CHB-par1 403; WRAN-B402 occupies frequency range CHB-part2 404.

Fig. 5 has provided on the temporal frequency coordinate curve WRAN-A501 and WRAN-B502 is carried out the division of frequency resource and share.Among the figure, channel CHB is divided into 0,1 ..., N-1 is N subchannel altogether, and its sub-channels [k+n, N-1] is assigned to WRAN-A501, and subchannel [0, k-n] is assigned to WRAN-B502.For fear of of the interference of two wireless zone connecting systems that overlap each other, reserve 2n subchannel as protection interval 503 to adjacent sub-channel.Therefore, the effective bandwidth of distributing to WRAN-A system 501 is:

$\mathrm{BW}(\mathrm{WRAN}-A)=\mathrm{\α}(1-\frac{2n}{N})\·\mathrm{BW}\_\mathrm{CHB}$

Distribution with the effective bandwidth of WRAN-B system 502 is:

$\mathrm{BW}(\mathrm{WRAN}-B)=(1-\mathrm{\α})(1-\frac{2n}{N})\·\mathrm{BW}\_\mathrm{CHB}$

Protection 503 bandwidth at interval is:

$\mathrm{BW}\left(\mathrm{GB}\right)=\frac{2n}{N}\·\mathrm{BW}\_\mathrm{CHB}$

A. wherein protect spacing parameter n value relevant according to the transmitted power P of base station among crossover region area S between the adjacent WRAN system and the WRAN; Bandwidth allocation parameters α value is determined according to the bandwidth request information that the lower WRAN base station of other priority sends by the higher WRAN system base-station of priority.Concrete Determination of priority and control signaling alternately and will in the detailed description of the invention part, be described in detail.

Fig. 6 has provided the operational flow diagram according to system of the present invention, and Fig. 7 has provided based on the control signaling between each WRAN system of the present invention.According to Fig. 6 and Fig. 7, WRAN system operation step of the present invention is as follows:

1.WRAN-A and each CPE among the WRAN-B carries out the frequency spectrum detecting, and the corresponding detection result is sent to separately base station, determines the idle frequency range that next hop period can find by it;

2.WRAN-A the base station 702 of base station 701 and WRAN-B is the claim information of WRAN broadcasting towards periphery Announcement_use_CHB703 respectively; Monitor simultaneously from around the broadcast message of other WRAN; (herein, thus we suppose that WRAN-A at first detects idle channel CHB prior to WRAN-B base station 702 broadcasting statement signals with being without loss of generality.Therefore the WRAN-A system has higher priority here);

3. if the statement Announcement_use_CHB703 information that is sent by WRAN is not on every side received in WRAN-A base station 701 in waiting time, then following one-period dynamic frequency hopping carry out data transmit-receive to CHB; If statement signal Announcement_use_CHB704 and Announcement_use_CHC by WRAN-B base station 702 WRAN broadcasting are towards periphery received at waiting time in WRAN-A base station 701, then WRAN-A still following one-period dynamic frequency hopping carry out data transmit-receive to CHB; If WRAN-A base station 701 only receives that at waiting time statement signal Announce_use_CHB704 and timestamp demonstration by WRAN-B base station 702 WRAN broadcasting towards periphery are later than WRAN-A, then determine the high priority status of WRAN-A system thus;

4.WRAN-B base station 702 sends solicited message Req_co-use_CHB705 to the WRAN-A base station 701 of sharing CHB; And send bandwidth request information Req_Bandwidth_WRAN-B706 simultaneously;

5.WRAN-A base station 702 is after receiving the solicited message Req_co-use_CHB705 that WRAN-B base station 702 sends, according to bandwidth request information Req_Bandwidth_WRAN-B706 and self system demand to QoS of survice, whether decision shares CHB;

6.WRAN-A thereby the response message Rep_co-use-CHB707 that base station 701 sends shared channel determines whether to participate in the bandwidth sharing of CHB;

If 7. but the WRAN-A system allows WRAN-B and its shared channel B, 701 scheduling of WRAN-A base station and distribution respective free frequency range are to WRAN-A and WRAN-B, and transmission allocated bandwidth control information Bandwidth allocation_CHB708 to WRAN-B base station 702.

Claims (9)

1. the frequency spectrum cooperation method in the dynamic frequency hopping wireless area network comprises step:

CPE among all WRAN carries out frequency spectrum detecting and the relevant free channel information control base station extremely separately of feedback;

Be in the frequency spectrum resource distribution of the WRAN system of frequency spectrum collision status by the WRAN decision of high priority.

2. method according to claim 1 is characterized in that the WRAN that at first detects idle channel CHB has high priority.

3. method according to claim 1 is characterized in that having the WRAN of high priority at first in idle channel CHB transceive data.

4. method according to claim 1 is characterized in that described frequency spectrum resource distribution comprises that non-orthogonal subcarrier allocation of employing or positive jiao zi carry distribution.

5. method according to claim 1 is characterized in that described frequency spectrum resource divides timing protection width at interval also to determine jointly with multiple factors such as the type of subcarrier, crossover region area between the WRAN and transmitted powers.

6. method according to claim 1 is characterized in that described frequency spectrum resource distribution comprises:

When the WRAN with high priority receives the solicited message of the shared channel CHB that another WRAN sends and bandwidth request information, whether the demand of QoS of survice is determined shared channel CHB according to bandwidth request information and self system.

7. method according to claim 6, it is characterized in that allowing another WRAN and its shared channel CHB if having the WRAN of high priority, then have the WRAN base station scheduling of priority and distribute the respective free frequency range, and send the allocated bandwidth control information to another WRAN base station to the WRAN with priority and another WRAN.

8. method according to claim 7 is characterized in that having the bandwidth of the WRAN of priority by the following formula distribution:

$\mathrm{BW}(\mathrm{WRAN}-A)=\mathrm{\α}(1-\frac{2n}{N})\·\mathrm{BW}\_\mathrm{CHB}.$

9. method according to claim 7 is characterized in that distributing by following formula the bandwidth of another WRAN:

$\mathrm{BW}(\mathrm{WRAN}-B)=(1-\mathrm{\α})(1-\frac{2n}{N})\·\mathrm{BW}\_\mathrm{CHB}.$

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