CN101309166B - Transmission parameter acquiring method and apparatus in wireless communication system - Google Patents

Abstract

Disclosed are an acquiring method and a device of the transmission parameter in a wireless communication system; wherein, the transmission parameter includes the network throughput parameter in the wireless communication system; the mode of computing the throughput parameter includes that: firstly, the time for sending data in the time slot ensuring mechanism of the active period of the superframe and the time length of the time slot ensuring mechanism are acquired; and then, the ratio of the time for sending data in the time slot ensuring mechanism of the active period of the superframe and the time length of the time slot ensuring mechanism is computed to be the result of the throughput parameter; Thereby, the acquiring method and the device of the transmission parameter in the wireless communication system improves the accuracy of the estimation of the network throughput parameter and provides a reliable and accurate analyzing tool for the network performance estimation.

Description

The acquisition methods of transmission parameter and device in the wireless communication system

Technical field

The present invention relates to wireless communication technology field, relate in particular to the time delay in a kind of wireless communication system and the analytical technology of throughput.

Background technology

In WPAN (wireless personal domain network) and WSN cordless communication networks such as (wireless sensor networks), corresponding network work pattern mainly comprises: beacon enable mode and non-beacon enable mode.Wherein, under the beacon enable mode, network coordinator periodically sends superframe with organizing communication, and the assurance of timely service is provided, and by in superframe, distributing time slot to guarantee transmission quality; Under non-beacon enable mode, all nodes in the network are by CSMA (access of carrier sense multiple spot)/CA (conflict is avoided) the algorithm competitive channel of non-time slot, non-beacon enable mode has the advantage of self-organization, but it can't provide the assurance of time and quality.

Under the beacon enable mode, BI (BeaconInterval, beacon interval) expression, the i.e. duration of superframe are used in the transmission of two continuous beacon frames at interval.As shown in Figure 1, this BI specifically can be divided into active period (active) and non-active period (Inactive), and wherein, active period comprises Beacon (beacon) frame transmit time segments, CAP (contention access period) and CFP (non-competing access-hours).

In Fig. 1, the active period of superframe is called the duration SD of superframe, SD is divided into 16 isometric slot (time slot) altogether, and the parameters such as timeslot number that the length of each slot and contention access period comprise are set by network coordinator, and the beacon frame when beginning by superframe is broadcast to whole network.In the non-active period of superframe, node does not send data, enters resting state to save energy.

Described BI and SD mainly by BO (Beacon Order, beacon frame index) and two parameter decisions of SO (Superframe Order, superframe index), are specially:

BI＝aBaseSuperframeDuration×2 ^BO 0≤BO≤14 (1)

SD＝aBaseSuperframeDuration×2 ^SO 0≤SO≤BO≤14 (2)

Wherein, parameter aBaseSuperframeDuration is the minimum length of superframe when SO=0, at present, is generally 960symbols (1symbol=4bits), i.e. 15.36ms.

In time period, the minimum length of CAP period is aMinCAPLength (440 symbols) at SD, but if use GTS (ensuring mechanism time slot) then allows the length of CAP to be worth less than this.In the CAP stage, node is by the CSMA/CA algorithm competitive channel of time slot.Node distributes GTS in the CAP period to the telegon application, successfully obtain GTS after, node just can be in the GTS of oneself direct transmission data, do not need to use CSMA/CA algorithm competitive channel.

Can only distribute 7 GTS in a superframe at most, each GTS is made up of several slots.The node that is assigned to GTS must guarantee to finish communication before GTS finishes.

In cordless communication network, for ease of the transmission situation in the awareness network, need the transmission parameter of estimation network usually, corresponding transmission parameter comprises time delay, network throughput etc.

Wherein, the estimation mode of described throughput parameter is:

${\mathrm{Th}}_{\max }=\min \left(\begin{array}{c}\frac{b+r\·\mathrm{Ts}}{\mathrm{BI}},\\ \max \left(\begin{array}{c}\mathrm{Ts}-(N_{\mathrm{LIFS}}-1)\·\mathrm{LIFS}-\mathrm{\Δ}\left(\mathrm{IFS}\right),\\ \mathrm{Ts}-N_{\mathrm{SIFS}}\·\mathrm{SIFS}\end{array}\right)\frac{C}{\mathrm{BI}}\end{array}\right);$

In the formula, Th _MaxBe throughput, b is the length of bursty data, and r is the slope of data arrival curve, N is the quantity of long frame or short frame, and LIFS is long frame interFrameGap, and SIFS is short frame interFrameGap, C is a channel capacity, and Δ (IFS) is the IFS (interFrameGap) of last frame, can be LIFS or SIFS.

In implementing process of the present invention, the inventor finds to exist at least in the prior art following problem:

In existing throughput estimation procedure, what adopt is that data transmission period among the CFP is compared with BI, be its calculating be relative throughput in the network, in computing network throughput process, do not consider the data that to transmit in the CAP period, so the estimated result of throughput of the prior art also exists the not good problem of accuracy.

Summary of the invention

Embodiments of the invention provide the acquisition methods and the device of transmission parameter in a kind of wireless communication system, with the accuracy of the estimated result that improves transmission parameter.

The embodiment of the invention provides the method for estimation of transmission parameter in a kind of wireless communication system, and described transmission parameter comprises the throughput parameter in the wireless communication system, and the method for calculating described throughput parameter comprises:

Obtain the time and the ensuring mechanism time slot length that are used to send data in the ensuring mechanism time slot of the active period in the superframe;

Calculate in the ensuring mechanism time slot of active period and be used to send the time of data and the ratio of ensuring mechanism time slot length, and with described result of calculation as described throughput parameter.

The embodiment of the invention provides the estimation unit of transmission parameter in a kind of wireless communication system, comprises the throughput estimation unit that is used for calculating the throughput parameter of estimating wireless communication system in the described device, and described throughput estimation unit comprises:

The first estimated parameter acquiring unit is used for obtaining the time and the ensuring mechanism time slot length that are used to send data in the ensuring mechanism time slot of active period of superframe;

The throughput computing unit, be used for the information obtained according to the described first estimated parameter acquiring unit, calculate in the ensuring mechanism time slot of active period and be used to send the time of data and the ratio of ensuring mechanism time slot length, and with described result of calculation as the throughput parameter in the described transmission parameter.

The technical scheme that is provided by the embodiment of the invention described above as can be seen, the embodiment of the invention provides a kind of implementation of CFP period network throughput of accurate estimation superframe, improve the accuracy of the throughput parameter Estimation in the network, thereby provide reliably analysis tool accurately for network performance evaluation.

Description of drawings

Fig. 1 is a superframe structure schematic diagram in the prior art;

Fig. 2 is that the transmission mode schematic diagram is confirmed and confirmed to the nothing among the GTS of prior art;

Fig. 3 is the relation curve schematic diagram one between throughput and the SO in the embodiment of the invention;

Fig. 4 is the relation curve schematic diagram two between throughput and the SO in the embodiment of the invention;

Fig. 5 is that the data in the embodiment of the invention arrive and service curve synoptic diagram one;

Fig. 6 is that the data in the embodiment of the invention arrive and service curve synoptic diagram two;

Fig. 7 is that the data in the embodiment of the invention arrive and service curve synoptic diagram three;

Fig. 8 is the relation curve schematic diagram between time delay and the SO in the embodiment of the invention;

The structural representation of the device that Fig. 9 provides for the embodiment of the invention.

Embodiment

In the embodiment of the invention, the scheme of obtaining of transmission parameter in the corresponding wireless communication system is provided, wherein, described transmission parameter comprises the throughput parameter in the wireless communication system, and the method for calculating described throughput mainly comprises: at first, obtain the time and the ensuring mechanism time slot length that are used to send data in the ensuring mechanism time slot of the active period in the superframe; Afterwards, calculate in the ensuring mechanism time slot of active period and be used to send the time of data and the ratio of ensuring mechanism time slot length, and with described result of calculation as described throughput, thereby obtain throughput result of calculation accurately.

In the embodiment of the invention, described transmission parameter can also comprise delay parameter, and the method for calculating described time delay comprises: according to the described time delay of function calculation that sends data in the length of bursty data and the wireless communication system.

Therefore, in embodiments of the present invention, specifically be to carry out the estimation of transmission parameters such as network throughput and time delay, thereby can obtain transmission parameter accurately according to the arrival situation of node data in the network and the parameter setting of superframe structure.

For ease of the understanding to the embodiment of the invention, below in conjunction with accompanying drawing, the computing network throughput that the embodiment of the invention is provided and the specific implementation of time delay parameter are elaborated.

(1) computational process of network throughput

In the embodiment of the invention, the throughput Th that is defined in the CFP stage is that GTS is used to send the time of data and the ratio of GTS length.

Transmission mode in GTS includes the transmission mode of confirming and not having affirmation respectively as shown in Figure 2, in Fig. 2, and T _s(be T _Slot) be the duration of a slot, so:

$T_{\mathrm{slot}}=\frac{\mathrm{SD}}{16}\·\frac{1}{C}=\frac{\mathrm{aBaseSuperframeDuration}}{C}\×2^{\mathrm{SO}-4}---\left(3\right)$

Working condition definition of T according to reality _Slot=T _Data+ T _Idle=T _Data+ T _Over+ T _Waste, T wherein _DataBe the transmission time of Frame, T _OverBeing transmission time (if confirmation request) sum of IFS (interFrameGap) and Ack (affirmation), is the protocol overhead time of system, T _WasteIt then is the remaining time of transmission (transfer of data, IFS and Ack) back of finishing data.

For accurately estimating then to need corresponding throughput the operating position of the time slot among the GTS is analyzed, the operating position of corresponding GTS can comprise two kinds: a kind of slot of being (time slot) is fully utilized; Another kind is that slot partly is utilized.

In addition, for ease of describing, the length of supposing long frame is 840bits, and short frame length is 48bits, and adopts variables L ength to represent frame length; InterFrameGap LIFS is 160bits, and SIFS is 48bits; And, calculate for convenient, suppose only to include among the GTS slot.

To the computational process of the throughput under the different time-gap operating position be described below.

(1) the slot throughput computational process under the situation that is fully utilized

When sending burst length is the bursty data b required time of b during greater than a slot, then will have only T among the slot _DataAnd T _Over, and do not have T _Waste

Like this, when sending long frame, the frame number N that can send among slot then _lFor:

In formula (4), the outer long frame number that is sent of last frame is removed in first expression, and last frame may be short frame.

Therefore, in a time slot, be used to send the time (not comprising the interFrameGap time) of bursty data b

For:

$T_{\mathrm{data}}^l=T_{\mathrm{slot}}-(N_l-1)\frac{\mathrm{LIFS}}{C}-\mathrm{\δ}---\left(5\right)$

In formula (5), δ is the interFrameGap of last frame, and it can be

Also can be

When sending short frame, the frame number N that can send among slot _sFor:

At this moment, in a time slot, be used to send the time (not comprising interFrameGap) of bursty data b

For:

$T_{\mathrm{data}}^s=T_{\mathrm{slot}}-N_s\frac{\mathrm{SIFS}}{C}---\left(7\right)$

Therefore, the throughput Th under slot is fully utilized situation _FullFor:

${\mathrm{Th}}_{\mathrm{full}}=\max (T_{\mathrm{data}}^s/T_{\mathrm{slot}},T_{\mathrm{data}}^l/T_{\mathrm{slot}})---\left(8\right)$

(2) the throughput computational process under the slot situation about partly being utilized

During less than a slot, the data of transmitting in a slot can not surpass α (T at bursty data b required time _Slot)=b+rT _Slot, wherein, r is the speed that data arrive, b is the length of bursty data;

At this moment, corresponding throughput Th _PartFor:

${\mathrm{Th}}_{\mathrm{part}}=\min \left\{\begin{array}{c}\frac{b+{\mathrm{rT}}_{\mathrm{slot}}}{C\·T_{\mathrm{slot}}}\\ \max (T_{\mathrm{data}}^s/T_{\mathrm{slot}},T_{\mathrm{data}}^l/T_{\mathrm{slot}})\end{array}\right.---\left(9\right)$

As can be seen, formula (9) is suitable for slot and partly is utilized two kinds of situations by whole utilizations and slot, therefore, can determine that the throughput Th in CFP stage is:

$\mathrm{Th}=\min \left\{\begin{array}{c}\frac{b+{\mathrm{rT}}_{\mathrm{slot}}}{C\·T_{\mathrm{slot}}}\\ \max (T_{\mathrm{data}}^s/T_{\mathrm{slot}},T_{\mathrm{data}}^l/T_{\mathrm{slot}})\end{array}\right.---\left(10\right)$

Wherein, suppose that b is constant, r changes, and then the relation curve that can obtain throughput and SO (superframe index) according to formula (10) as shown in Figure 3; Suppose that r is constant, b changes, and then the relation curve that can obtain throughput and SO according to formula (10) as shown in Figure 4.

(2) computational process of time delay

In the time-delay calculation process,,, and only contain 1 slot (time slot) among the GTS and the computational process of time delay is analyzed explanation for example specifically only having distributed a GTS in the superframe for ease of understanding.

Suppose that BO (beacon frame index) and SO (superframe index) remain unchanged in continuous a period of time, and when node has the transfer of data demand, can apply for GTS in the CAP period.

Based on above-mentioned hypothesis, have at node to send demand data to sending described data, during the maximum time interval be T=BI-SD+SD-T _Slot=BI-T _Slot, promptly when current C FP finishes, there are data to arrive, and send at the CFP of next superframe, corresponding data arrival curve and service curve with Fig. 5 SD that moves to left in time, then can obtain data arrival curve shown in Figure 6 and service curve as shown in Figure 5.

In Fig. 6, the data arrival curve is: α (t)=b+rt, slope r are the arrival rates of data, and b is the length of bursty data; The maximum delay D that then receives data and send data when equating is:

D＝h(α，β)＝max{inf{τ≥0:α(s)≤β(s+τ)}} s≥0 (11)

In the formula, Inf refer to be the value that satisfies under which kind of condition, τ is for sending the time of data;

At this, only consider to be used among the GTS send the T of data _DataSo the service curve is a step function, be designated as β (t), like this, in first superframe, the data volume that the CFP period receives is:

In formula (12), definition (t) +=max (O, t).So, being generalized to k the Data Receiving in the superframe, then corresponding step function is:

So the service curve is a step function, promptly $\mathrm{\β}\left(t\right)=\underset{k}{\mathrm{\Σ}}{\mathrm{\β}}^k\left(t\right),$ Specifically can be with reference to shown in Figure 7.

In Fig. 7, the t value when time delay D is data arrival for b, according to formula (13) as can be known, if b=(k-1) T _DataC+C[t-(kBI-T _Slot)], the t value of then finding the solution acquisition just is time delay D, that is:

$D^k=\frac{b-(k-1)T_{\mathrm{data}}C}{C}+\mathrm{kBI}-T_{\mathrm{slot}}$

$=\frac{b}{C}+\mathrm{kBI}-T_{\mathrm{slot}}-(k-1)T_{\mathrm{data}}$ (k-1)CT _data≤b≤kCT _data (14)

Further, be generalized to the situation that contains n slot (n≤15) among the GTS, then time delay is:

${D_n}^k=\frac{b}{C}+\mathrm{kBI}-n{T}_{\mathrm{slot}}+n(k-1)T_{\mathrm{data}}+m{T}_{\mathrm{idle}}$ (k-1)nT _dataC≤b≤knT _dataC (15)

Wherein,

Based on formula (15), then the relation curve of corresponding C FP time delay D and SO as shown in Figure 8.

In sum, in the embodiment of the invention, be throughput and the time delay of CFP period are carried out analytical calculation, thereby improved the result's that analytical calculation obtains accuracy greatly, for the efficient use of GTS provides scientific foundation according to the arrival of Network and the actual conditions of transmission.

The embodiment of the invention also provides the estimation unit of transmission parameter in a kind of wireless communication system, its specific implementation structure as shown in Figure 9, described device can comprise the throughput estimation unit that is used for calculating the throughput parameter of estimating wireless communication system, and described throughput estimation unit specifically can comprise:

(1) first estimated parameter acquiring unit

This unit specifically can be used for obtaining time and the ensuring mechanism time slot length that is used to send data in the ensuring mechanism time slot of active period of superframe;

(2) throughput computing unit

This unit specifically can be used for the information obtained according to the described first estimated parameter acquiring unit, calculate in the ensuring mechanism time slot of active period and be used to send the time of data and the ratio of ensuring mechanism time slot length, and with described result of calculation as the throughput value in the described transmission parameter;

And described throughput computing unit specifically comprises:

The second estimated parameter acquiring unit is used to obtain the interFrameGap δ of last frame, the quantity N of short frame or long frame _sAnd N _l, the slope r of data arrival curve, the interFrameGap LIFS and the SIFS of long frame or short frame;

The throughput determining unit is used for the information that the parameter obtained according to the described second estimated parameter acquiring unit and the described first estimated parameter acquiring unit obtain, and adopts following formula to carry out the calculating of throughput:

Throughput $\mathrm{Th}=\min \left\{\begin{array}{c}\frac{b+{\mathrm{rT}}_{\mathrm{slot}}}{C\·T_{\mathrm{slot}}}\\ \max (T_{\mathrm{data}}^s/T_{\mathrm{slot}},T_{\mathrm{data}}^l/T_{\mathrm{slot}})\end{array}\right.;$

Wherein, $T_{\mathrm{data}}^l=T_{\mathrm{slot}}-(N_l-1)\frac{\mathrm{LIFS}}{C}-\mathrm{\δ},$ ? $T_{\mathrm{data}}^s=T_{\mathrm{slot}}-N_s\frac{\mathrm{SIFS}}{C}.$

For ease of carrying out the calculating of delay parameter, described device can also comprise the time delay estimation unit, is used for estimating the delay parameter of transmission parameter, and specifically is used to adopt following formula to carry out time-delay calculation:

Time delay ${D_n}^k=\frac{b}{C}+\mathrm{kBI}-{\mathrm{nT}}_{\mathrm{slot}}+n(k-1)T_{\mathrm{data}}+{\mathrm{mT}}_{\mathrm{idle}},$ And (k-1) nT _DataC≤b≤knT _DataC;

Wherein, D _n ^kBe time delay, b is the length of bursty data, and c is a channel capacity, and k is a superframe quantity, and n is the timeslot number in the ensuring mechanism time slot of single superframe, T _DataBe the Frame length in the ensuring mechanism time slot, T _SlotBe the length of ensuring mechanism time slot, T _IdleBe the idle length in the ensuring mechanism time slot.

In sum, the realization of the embodiment of the invention can effectively improve the accuracy of the throughput parameter Estimation in the network, and the estimation mode of corresponding delay parameter also is provided simultaneously, thereby provides reliably analysis tool accurately for network performance evaluation.

The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.

Claims (4)

1. the acquisition methods of transmission parameter in the wireless communication system, described transmission parameter comprises the throughput parameter in the wireless communication system, it is characterized in that, the method for calculating described throughput parameter comprises:

Obtain the time and the ensuring mechanism time slot length that are used to send data in the ensuring mechanism time slot of the active period in the superframe;

Be used to send the time of data and the ratio of ensuring mechanism time slot length in the ensuring mechanism time slot of calculating active period, described result of calculation is described throughput parameter;

Described throughput CALCULATION OF PARAMETERS mode is specially:

Throughput $\mathrm{Th}=\min \left\{\begin{array}{c}\frac{b+{\mathrm{rT}}_{\mathrm{slot}}}{C\·T_{\mathrm{slot}}}\\ \max (T_{\mathrm{data}}^s/T_{\mathrm{slot}},T_{\mathrm{data}}^l/T_{\mathrm{slot}})\end{array}\right.;$

Wherein, $T_{\mathrm{data}}^l=T_{\mathrm{slot}}-(N_l-1)\frac{\mathrm{LIFS}}{C}-\mathrm{\δ},$ $T_{\mathrm{data}}^s=T_{\mathrm{slot}}-N_s\frac{\mathrm{SIFS}}{C},$ δ is the interFrameGap of last frame, N _sAnd N _lBe respectively the quantity of short frame or long frame, r is the slope of data arrival curve, and LIFS and SIFS are respectively the interFrameGap of long frame or short frame, and b is the length of bursty data, and C is a channel capacity,

Be the length of the short data frame in the ensuring mechanism time slot,

Be the length of the long data frame in the ensuring mechanism time slot, T _SlotLength for ensuring mechanism time slot.

2. method according to claim 1 is characterized in that described transmission parameter also comprises delay parameter, and the method for calculating described delay parameter comprises:

According to the described delay parameter of function calculation that sends data in the length of bursty data and the wireless communication system;

The computational methods of described delay parameter specifically comprise:

Delay parameter ${D_n}^k=\frac{b}{C}+\mathrm{kBI}-{\mathrm{nT}}_{\mathrm{slot}}+n(k-1)T_{\mathrm{data}}+{\mathrm{mT}}_{\mathrm{idle}},$ And (k-1) nT _DataC≤b≤knT _DataC;

Wherein, D _n ^kBe time delay, b is the length of bursty data, and C is a channel capacity, and k is a superframe quantity, and n is the timeslot number in the ensuring mechanism time slot of single superframe, T _DataBe the Frame length in the ensuring mechanism time slot, T _SlotBe the length of ensuring mechanism time slot, T _IdleBe the idle length in the ensuring mechanism time slot, BI represents the duration of superframe.

3. the deriving means of transmission parameter in the wireless communication system comprises the throughput estimation unit that is used for calculating the throughput parameter of estimating wireless communication system in the described device, it is characterized in that described throughput estimation unit comprises:

The first estimated parameter acquiring unit is used for obtaining the time and the ensuring mechanism time slot length that are used to send data in the ensuring mechanism time slot of active period of superframe;

The throughput computing unit, be used for the information obtained according to the described first estimated parameter acquiring unit, calculate in the ensuring mechanism time slot of active period and be used to send the time of data and the ratio of ensuring mechanism time slot length, and with described result of calculation as the throughput parameter in the described transmission parameter;

Described throughput computing unit specifically comprises:

The second estimated parameter acquiring unit is used to obtain the interFrameGap δ of last frame, the quantity N of short frame or long frame _sAnd N _l, the slope r of data arrival curve, the interFrameGap LIFS and the SIFS of long frame or short frame;

The throughput determining unit is used for the information that the parameter obtained according to the described second estimated parameter acquiring unit and the described first estimated parameter acquiring unit obtain, and adopts following formula to carry out described throughput CALCULATION OF PARAMETERS:

Throughput $\mathrm{Th}=\min \left\{\begin{array}{c}\frac{b+{\mathrm{rT}}_{\mathrm{slot}}}{C\·T_{\mathrm{slot}}}\\ \max (T_{\mathrm{data}}^s/T_{\mathrm{slot}},T_{\mathrm{data}}^l/T_{\mathrm{slot}})\end{array}\right.;$

Wherein, $T_{\mathrm{data}}^l=T_{\mathrm{slot}}-(N_l-1)\frac{\mathrm{LIFS}}{C}-\mathrm{\δ},$ $T_{\mathrm{data}}^s=T_{\mathrm{slot}}-N_s\frac{\mathrm{SIFS}}{C},$ δ is the interFrameGap of last frame, N _sAnd N _lBe respectively the quantity of short frame or long frame, r is the slope of data arrival curve, and LIFS and SIFS are respectively the interFrameGap of long frame or short frame, and b is the length of bursty data, and C is a channel capacity,

Be the length of the short data frame in the ensuring mechanism time slot,

Be the length of the long data frame in the ensuring mechanism time slot, T _SlotLength for ensuring mechanism time slot.

4. device according to claim 3 is characterized in that described device also comprises the time delay estimation unit, is used to adopt following formula to carry out delay parameter and estimates:

Delay parameter ${D_n}^k=\frac{b}{C}+\mathrm{kBI}-{\mathrm{nT}}_{\mathrm{slot}}+n(k-1)T_{\mathrm{data}}+{\mathrm{mT}}_{\mathrm{idle}},$ And (k-1) nT _DataC≤b≤knT _DataC;

Wherein,

D _n ^kBe time delay, b is the length of bursty data, and C is a channel capacity, and k is a superframe quantity, and n is the timeslot number in the ensuring mechanism time slot of single superframe, T _DataBe the Frame length in the ensuring mechanism time slot, T _SlotBe the length of ensuring mechanism time slot, T _IdleBe the idle length in the ensuring mechanism time slot, BI represents the duration of superframe.

Images