CN101116269A - Wireless communication method and apparatus for managing radio resources using silent measurement periods - Google Patents

Abstract

A silent measurement period (SMP) for a selected channel in an allowable channel set (ACS) of the access point (AP) is set. During the SMP, the AP does not serve wireless transmit/receive units (WTRUs) within its coverage area and reserves its channels for other BSSs. A normal operating channel of the AP is changed to the selected channel upon initialization of the SMP. Characteristics of the selected channel is measured during the SMP. The operating channel of the AP is changed back to the normal operating channel when the duration of the SMP expires.

Description

Use the wireless communications method and the device of managing radio resources during the measurement free of interest

Technical field

RRM (RRM) in the relevant wireless communication system of the present invention.Specifically, the RRM of (SMPs) during the use measurement free of interest in the relevant wireless communication system of the present invention.

Background technology

Comprise in the wireless communication system of a plurality of infrastructure service set (BSSs) that one the access point (AP) of a BSS is required to listen to the data packet that sends from contiguous BSSs sometimes.In addition, an AP may be required to measure the position standard of the external disturbance in the different channel because supporting advanced RRM function such as frequency selection, load balance or power management.But an AP also must support to commute the transmission and the reception of the package of the wireless transmission/receive unit (WTRUs) in himself BSS.One AP be used for himself BSS in the channel that communicates of WTRUs may be different from the used any channel of contiguous BSSs or be different from order to measure the channel of external disturbance.

Because the cost restriction, many APs only comprise a receiver.Therefore, AP can not measure external disturbance or listen to the package that sends from other BSSs with regard to a different channel when it communicate with regard to the WTRUs in a channel and himself BSS.Even the channel that an AP self BSS is used for operating is identical with the channel of pending measurement, these are measured the news of operations in the BSS of this AP and are engaged in may being difficult to carry out when busy.

Therefore, expect to have a kind of mechanism,, and this AP caused few interruption with the communicating by letter of WTRUs in himself BSS so as to the package that an AP can be measured external disturbance and send from contiguous BSSs (comprising with different channel fortune author).

Summary of the invention

The present invention allow an AP measure to disturb and the package that sends from other BSSs so that manage a Radio Resource that may comprise in the wireless communication system of a plurality of BSSs efficiently.This AP covers the ripple district to one of a BSS provides service.In a preset time, trigger a SMP of the selected channel in the tolerable channel set (ACS) of this AP.This AP waits that this channel becomes that idle state sends a SMP notification message then so that (as far as possible) is suppressed at during this SMP the encapsulated delivery of being sent by the WTRUs in himself BSS.

During this SMP, this AP does not provide service so that measure with regard to a selected channel to the WTRUs that covers at it in ripple district.After this SMP began, (optionally) changed the operation channel of the receiver in this AP into this selected channel.When this SMP expires, the operation channel of this AP is gained the channel (prerequisite is this two channels difference) that this AP uses before this SMP begins.Be another channel arrangement one new SMP in this ACS then.

The package that this SMP mechanism allows this AP to measure external disturbance and send from other BSSs, the communication to the WTRUs relevant with this AP simultaneously causes few interruption.

Description of drawings

Can be from the clearer the present invention of understanding of preferred embodiment of the present invention who proposes with way of example to be described in detail, in the accompanying drawing with reference to the accompanying drawing formula:

Fig. 1 draws a wireless communication system according to a preferred embodiment of the present invention, and it comprises a plurality of WTRUs and and utilizes SMPs to support the AP of advanced RRM function;

Fig. 2 one is rendered in the flow chart of the intrasystem program of Fig. 1, this program be used for have through judgement a communication medium can with after send by this AP a SMP during and after change channel and EDT value;

Fig. 3 one is rendered in the flow chart of the intrasystem program of Fig. 1, and this program is utilized the SMPs managing radio resources of a plurality of channels in the ACS; And

Fig. 4 is a Time Index Chart of Fig. 3 program.

Embodiment

Hereinafter, the non-limitation of term " WTRU " comprises a subscriber equipment (UE), a mobile radio station, is fixed or the device of moving user unit, a calling set or any type that other can operate in a wireless environment.

Hereinafter, the tipping that is situated between of the non-limitation of term " AP " wireless environment that comprises an access point, a B node, a site controller (sitecontroller), a base station or any other type is put.

Feature of the present invention can be merged in the integrated circuit (IC) or be configured in one and comprise in the circuit of a plurality of interconnecting assemblies.

Fig. 1 is a wireless communication system, its comprise one with the AP 105 of a plurality of WTRUs 110 selective communications.AP 105 uses SMPs to support advanced RRM function.AP 105 comprises a transceiver 115, a RRM unit 120 and a memory 125.It will be appreciated that each block shown in Figure 1 is the representative of a specific function.Many persons can be merged into single or multiple unit in the middle of these functions.Therefore, the present invention's function dividing mode shown in the dependency graph not.In addition, be not all functions as shown in Figure 1 all be that to carry out the present invention institute necessary, these functions are just drawn in order to allow the people understand.

The present invention uses clean channel assessment (CCA) function, and this function has concrete regulation in IEEE 802.11 standards.The role of the CCA function of one IEEE, 802.11 devices (AP or a WTRU) points out when communication medium is " busy ".One IEEE, 802.11 devices are avoided emission when communication medium is busy.In addition, the package that an idle receiver can trial and error decoding one enters when the CCA function begins to point out that communication medium is just busy.

In AP 105, other entity of 115 pairs one wireless communication systems of transceiver such as WTRUs 110 send communication and from these entity received communications.The characteristic of the signal that measurement sends via a radio channel, for example received signal intensity indication (RSSI), this CCA function that receives package points out that the position of duration that communication medium is just busy or external disturbance is accurate.

In AP 105, RRM unit 120 receives the information relevant with the content of deciphering package, such as source address and destination-address, packet type or similar information.As hereinafter describing in detail, RRM unit 120 provides the whole time of the running of AP105 to control, comprise the time relevant with SMP.For example all traditional RRM functions of an IEEE 802.11 devices (AP or a WTRU) of a wireless device are supported in RRM unit 120.For instance, the RRM function comprises judgement so as to the most suitable channel of running, the optimal transmission power position standard that reaches different packages and the function of message transmission rate.The RRM function also can comprise and is used for preventing or managing the function of being jammed that causes because of excessive news affair load.RRM unit 120 also is coupled to memory 125, this memory stores the parameter relevant with the running of AP 105, the numerical value (table 1) that wherein comprises ACS and in the calculating of timer, use.

In AP 105, memory 125 comprises ACS, and this ACS is defined in an AP who extends in the set of service (ESS) and is allowed to set so as to the channel of running.These channels should be all identical for all APs of an ESS.Channel in the ACS is preferably nonoverlapping, but this is not a necessary condition.Generally speaking, ACS can be the set of the possible channel of institute in the AP used band.But all APs are preferable to have identical ACS, and this ACS will only be a subclass of the possible channel of frequency band.

As previously mentioned, the role of CCA function points out that communication medium is idle or busy.Decide on selected CCA pattern, assert that promptly communication medium is busy if meet some condition.For instance, in a CCA pattern that usually is used for IEEE 802.11 systems, if received power is higher than an energy detection threshold (EDT) and detect a signal that produces by an IEEE 802.11 devices, assert that then communication medium is busy.

Table 1 is summed up out the parameter that involves in the process of setting up at SMPs (explaining with reference to Fig. 2 hereinafter).Can understand as those skilled in the art that, also may outside these parameters and numerical value, also use other parameter or replace with other parameter.

Symbol	Describe
		ACS	The tolerable channel set
T mpp fix	Produce fixed component at interval during the measurement free of interest
		T mpp var	Produce the amplitude of variable componenent at interval during the measurement free of interest
T mp dur	Duration during one measurement free of interest

Table 1

Fig. 2 is one according to the flow chart of program 200 of the present invention, its comprise in order to have through judgement a communication medium can send by AP 105 with the back SMP during change the method step of channel and EDT value after reaching.Program 200 is triggered in response to a SMP and is started, and sees for details hereinafter described with reference to figure Fig. 3.

With reference to Fig. 2, AP 105 judges at it that communication medium becomes and continues to wait (step 205) before available.In case communication medium becomes available, AP 105 waits a bit of effluxion (step 210) (a for example preferential interframe space (PIFS)) again.This short time can be predetermined or can be variable or at random.The reason that waits the short time process in step 210 is for fear of when sending SMP notice package and another packet collision.If this communication medium is available (step 215) at this short time through still being determined later, then program 200 advances to step 220.Otherwise, till program 200 is got back to step 205 by the time it is judged that this communication medium is available once more.In step 220, AP 105 sends SMP notice package (step 220).Role of this notice package reduces by AP 105 to provide a WTRU 110 in the BSS of service to send the possibility of a package during this SMP.

The mode of carrying out SMP notice package has multiple replacement scheme.In the replacement scheme of in an IEEE 802.11 systems, carrying out, this SMP notice package can be merely sends that (RTS) or a clear to send (CTS) package be formed and the address of " vacation " destination-address that possesses such as AP 105 self by a request, with one section duration T of communication medium reservation _{Mp_dur}Receive that the WTRUs 110 of this RTS or CTS package can be suppressed at the interior emission of duration of this package appointment.

Another selection, AP 105 can point out one section uncontested duration T by sending a beacon package _{Mp_dur}The initial contention free period of mode of beginning.The WTRUs 110 that receives this beacon package can suppress emission in the indicated contention free period of this package in the time.

Use that the through-put power of the SMP notice package that arbitrary method carries out is preferable to be set to one and lowly to avoid using the WTRUs 110 of identical operation channels to receive that this SMP notifies the value of package with AP 105 to being enough in contiguous BSSs.The reception of these WTRUs 110 can stop this WTRUs to carry out undermining the emission that this SMP assesses the ability of the channel utilization rate of contiguous BSSs on same channel.

Still with reference to Fig. 2, AP 105 (optionally) switches to a new selected channel (step 225) from a normality operation channel.Should new selected channel be will be so as to a channel of transmission from the data packet institute of other BSSs.In step 230, AP 105 changes the value of an EDT into a minimum value.This guarantees that this AP 105 can hear the package that receives with alap power level.

AP 105 measures and analyzes the received signal (step 235) on this newly selected channel.The measurement project can comprise but be not limited to: the duration that receives package; Receive the RSSI of package; The CCA function points out that communication medium is the available or busy duration; External disturbance position standard; Or similar item.When measuring the characteristic that receives package, AP 105 judges the duration (T of SMP _{Mp_dur}) whether expire (step 240).If the duration (T of SMP _{Mp_dur}) still not yet due, then AP 105 continues to measure and analyze the received signal of being somebody's turn to do on the new selected channel in step 235.If AP 105 judges the time (T of SMP in step 240 _{Mp_dur}) expire, then AP105 switches back normality operation channel (prerequisite is this two channels difference), and the value of EDT is gained normality value (that is the value before SMP) (step 245).

The present illustrates the program that all channels in the ACS are arranged SMPs with reference to figure Fig. 3 and Fig. 4.Fig. 3 is one according to the flow chart of program 300 of the present invention, and it comprises the SMPs method step of managing radio resources efficiently that utilizes a plurality of channels in the ACS.Fig. 4 is a Time Index Chart relevant with program 300.

With reference to as described in Fig. 2, it will be appreciated that AP 105 with the running of one specific (normality) operation channel as preamble, (optionally) switches to another channel during SMP, switch back this operations specific channel (prerequisite is this two channels difference) then after SMP.For this example, modern operation channel table with AP 105 is shown channel 0 (CHAN0), yet also can adopt any one transmission channel.

With reference to Fig. 3 and Fig. 4, in step 305, AP 105 is with a normality operation channel 0 running of an ACS.In step 310, AP 105 select in these ACS channel 1-N (CHAN 1-CHAN N) but in the middle of a channel and a communication medium time spent in a duration (T _{Mp_dur}) in an initial SMP, as among Fig. 4 with the T of SMP1 _{Mp_dur}1 expression.In step 315, AP 105 judges the duration (T of this SMP _{Mp_dur}) whether expire, and if expire then in step 320, AP 105 switches back normality operation channel 0 (CHAN 0).In step 325, have another channel requirement SMP to arrange in these ACS if AP 105 judges, then AP 105 set one in the end of SMP (SMP 1) last time and this ACS the interval (T between the beginning of the SMP next time (SMP2) of next channel (CHAN 2) _Mpp), as among Fig. 4 with T _Mpp1 and SMP2 represent.

Between setting by AP 105 every T _MppCan be a constant cycle, but be preferably a variable cycle by equation 1 decision:

T _Mpp=T _{Mpp_fix}+ C * T _{Mpp_var}Equation 1

T wherein _{Mpp_fix}And T _{Mpp_var}Be fixed value, and C is one between-1 to 1 variable.T _{Mpp_fix}Be approximate " the week rule " that SMP occurs.T _{Mpp_var}Be one to prevent to take place regularly the amplitude of " shake " at random that SMP occurs.Preferable, T _{Mpp_var}Much smaller than T _{Mpp_fix}This is also non-essential, because SMP can be periodically.So can alleviate the synchronized danger of some flow shapes (trafficpattern) in the measurement carried out and the tested BSSs with the implementation of aperiodicity mode during a SMP, this kind synchronia may cause some assessed value deviations.Therefore, the interval between SMPs must be according to T _MppValue and difference.As shown in Figure 4, T _Mpp1 less than T _Mpp2, and T _MppN (the T of the N time SMP _Mpp) greater than T _Mpp2.Interval T _MppLength change with the cycle according to equation 1 and different.

Because AP 105 can't provide service to himself WTRUs 110 during a SMP, for total time ratio (that is the ∑ T of SMP use _{Mp_dur}N/ (∑ T _MppN+ ∑ T _{Mp_dur}N)) should be very little.The total time ratio of SMP be one between the restriction one AP self transmission the loss of time with the distribution sufficient time for the compromise of the transmission of other BSS being measured between the use.

When preset proportion, consider support, because audio communication is highstrung for delay jitter for the sound load.This is to the duration (T of single SMP _{Mp_dur}) give a maximum value limit.On the other hand, single SMP must have the duration of enough length to allow receiving integral packets with a rational probalility of success from contiguous BSSs.

In step 335, AP 105 judges (T at interval _Mpp) whether expire, then this program is got back to step 310 if so, selects another channel (CHAN 2) from ACS.As shown in Figure 4, the T by SMP 2 _{Mp_dur}2 ..., the T of SMP N _{Mp_dur}N and T _Mpp2 ..., T _MppN continues repeating step 330,335,310,315 and 320, judges in the ACS to no longer include till the channel that requires the SMP arrangement in step 325.

By carrying out this program, to good all SMPs of all channel settings in the ACS.As shown in Figure 4, can an endless form set up SMPs to all channels in the ACS.Therefore, after AP 105 carried out the SMP N of N channel of ACS, AP 105 began to carry out another new circulation of SMP operation from the 1st channel of ACS.The operation channel that it will be appreciated that AP is the part of ACS under normal conditions, is sometimes the operation channel of himself to be arranged a SMP with AP.In addition, the SMPs that can a random sequence sets up all channels in the ACS.

The actual interval time between SMPs of it will be appreciated that equally may not be T just _MppN because communication medium may be busy when timer expires, forces AP 105 to wait a little for a long time sending SMP notice package as previously mentioned.

Though with regard to particular combinations feature of the present invention and assembly are described in preferred embodiment, each feature or assembly must be used alone (further feature and the assembly that do not possess preferred embodiment) or be used in combination to be with or without the various of further feature of the present invention and assembly.

Though reference one preferred embodiment is specially with accompanying drawing and the present invention of literal illustration, person skilled in the art person will appreciate that can not break away from foregoing scope of the present invention makes various variation with regard to form and details.

Claims (16)

1. serve in the wireless communication system of at least one wireless transmission/receive unit the method for the Radio Resource of this access point of management comprising an access point for one kind, this method comprises:

(a) make of the normality operation channel running of this access point with a tolerable channel set;

(b) but during this access point judges that a communication medium time spent makes initial one measurement free of interest of this access point;

(c) make this access point switch to a new channel of selecting from this tolerable channel set by this normality operation channel;

(d) after initial during this measurement free of interest that a duration is arranged, make this access point measure and analyze to the signal that this new channel received; And

When (e) duration during this measurement free of interest expires, make this access point switch back this normality operation channel.

2. the method for claim 1 is characterized in that this wireless transmission/receive unit can not attempt in the duration during this measurement free of interest this access point is posted a letter.

3. the method for claim 1 is characterized in that also comprising:

(f) during this measurement free of interest by after initial, make this access point change the set point of an energy detection threshold into a minimum value from a normality value; And

When (g) duration during this measurement free of interest expires, make this access point that this energy detection threshold value is gained this normality value.

4. the method for claim 1 is characterized in that this wireless communication system comprises a plurality of infrastructure services set, and this access point service be fated by these a plurality of basic service sets in one first infrastructure service set definition one cover the ripple district.

5. method as claimed in claim 4 is characterized in that this access point do not serve the wireless transmission/receive unit in it covers the ripple district in the duration during this measurement free of interest.

6. method as claimed in claim 4 is characterized in that this signal measured and that analyze is that at least one basic service set splice grafting beyond this first infrastructure service set is received from this basic service set is fated.

7. the method for claim 1 is characterized in that also comprising:

(h) this access point judges to arrange during whether another channel requirement measurement free of interest is arranged in this tolerable channel set;

(i) set one during nearest measurement free of interest, finish with this tolerable channel set in interval between beginning during next measurement free of interest of another channel;

(j) when this expires at interval, this access point switches to another new channel of selecting from this tolerable channel set by this normality operation channel; And

(k) but judge a communication medium time spent at this access point, during initial next measurement free of interest of this access point.

8. the method for claim 1 is characterized in that step (b) also comprises during this access point sends a measurement free of interest to this wireless transmission/receive unit to notify package.

9. the method for claim 1 is characterized in that step (b) but also is included in this access point judging a communication medium time spent, waits a bit of effluxion, and judges whether this communication medium is still available.

10. the method for the Radio Resource of the access point of a management one in a wireless communication system that comprises a plurality of infrastructure services set, this access point is served one of infrastructure service set and is covered the ripple district, and this method comprises:

(a), during this measurement free of interest, do not have the wireless transmission/receive unit relevant and attempt this access point is posted a letter with this access point to during the channel setting measurement free of interest in the tolerable channel set of this access point; And

(b) set interval during this measurement free of interest, this access point can be served the wireless transmission/receive unit in the ripple district of covering at this access point in this interval.

Cover the ripple district 11. an access point that utilizes managing radio resources during the measurement free of interest in a wireless communication system, this access point are served one of infrastructure service set, this access point comprises:

(a) memory that is used to store a tolerable channel set;

(b) transceiver, its channel that is used to select be used in this tolerable channel set sending package from other infrastructure service set during a measurement free of interest is used as an operation channel, and the duration that is used for during this measurement free of interest gains this operation channel the channel that is used before during this measurement free of interest to after date; And

(c) radio resource managing unit, itself and this transceiver and this memory communication, be used to set should select during the measurement free of interest of channel in this tolerable channel set, during this measurement free of interest, do not have the wireless transmission/receive unit relevant and attempt this access point is sent its package with this access point.

12. a wireless communication system, it comprises:

(a) at least one wireless transmission/receive unit; And

(b) access point of this wireless transmission/receive unit of service, wherein:

(c) this access point is with the normality operation channel running of a tolerable channel set;

(d) but this access point is judged a communication medium time spent at this access point, during initial one measurement free of interest;

(e) this access point switches to a new channel of selecting from this tolerable channel set by this normality operation channel;

(f) this access point is after initial during this measurement free of interest that a duration is arranged, and measures and analyzes at signal that this new channel received; And

Switch back this normality operation channel when (g) duration of this access point during this measurement free of interest expires.

13. system as claimed in claim 12 is characterized in that this wireless transmission/receive unit can not attempt in the duration during this measurement free of interest this access point is posted a letter.

14. system as claimed in claim 12, it is characterized in that this access point is changed the set point of an energy detection threshold into a minimum value from a normality value after initial during this measurement free of interest, and the duration of this access point during this measurement free of interest gains this normality value with this energy detection threshold value when expiring.

15. the integrated circuit that radio communication device is interior, it comprises:

(a) memory that is used to store a tolerable channel set;

(b) transceiver that is used for normality operation channel running;

(c) be used to the member of pointing out that a communication medium can be used;

(d) but be used for member during this communication medium time spent initial one measurement free of interest;

(e) be used for switching to the member of a new channel of selecting from this tolerable channel set by this normality operation channel;

(f) be used for the initial back member of measuring and analyzing the signal of receiving with this new channel during this measurement free of interest that a duration is arranged; And

(g) being used for duration during this measurement free of interest switches back the member of this normality operation channel when expiring.

16. an integrated circuit that utilizes managing radio resources during the measurement free of interest, this integrated circuit comprises:

(a) memory that is used to store a tolerable channel set;

(b) transceiver, its channel that is used to select to be used in this tolerable channel set to send package during a measurement free of interest is used as an operation channel, and the duration that is used for during this measurement free of interest gains this operation channel the channel that is used before during this measurement free of interest to after date; And

(c) radio resource managing unit, itself and this transceiver and this memory communication, be used to set during the measurement free of interest of this selected channel, set the interval during the measurement different free of interest of different channel in this tolerable channel set, and change the set point of an energy detection threshold.

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