CN103052131A - Energy consumption control method under delay constraint in wireless sensor network - Google Patents

Abstract

The invention relates to the field of wireless self-organizing networks and sensor networks, in particular to an energy consumption control method under delay constraint in a wireless sensor network. The energy consumption control method comprises the following steps of: generating a normal data packet and a pioneer data packet by a source node when data packets in the wireless sensor network need to be transmitted to a base station from the source node, wherein the normal data packet is used for transmitting the data packets, and the pioneer data packet is used for selecting nodes on a transmission path; determining the delay constraint of the nodes on the transmission path; computing the best sleep time of the nodes on the transmission path; applying the best sleep time to a duty ratio self-adaptive adjustment mechanism to obtain new duty ratio to transmit the data packets; and respectively recovering work cycles of all the nodes on the transmission path into an original state after all the data packets are transmitted to the base station. According to the energy consumption control method under the delay constraint in the wireless sensor network, on the premise that the constraint condition of the wireless sensor network on transmission delay is met, the energy consumption of the wireless sensor network is reduced to the maximum limit, and the service life of the wireless sensor network is prolonged.

Description

Consumption control method in a kind of radio sensing network under the time-delay constraint

Technical field

The present invention relates to wireless self-organization network and sensor network field, relate in particular to the consumption control method under the time-delay constraint in a kind of radio sensing network.

Background technology

The sensor node of radio sensing network (Wireless SensorNetwork is called for short WSN) generally is made of transducer, processor, memory, electric supply installation, antenna and drive unit.Because sensor node limited storage space and usually be deployed in inaccessible environment, and need Anneta module frequently image data to be transferred to network base station and so that be main energy source with battery, so in radio sensing network, energy consumption problem is its key problem.Progress along with microelectric technique and crystal technology, the energy consumption of processor module and sensor assembly becomes very low on the sensor node, energy consumption is mainly used in the antenna communication module, and therefore, the energy consumption that reduces the antenna communication module is the emphasis that prolongs sensor network life.

The fourdrinier wire network life-span that had finished in recent years as can be seen from Table 1 the wireless sensing network system that moves is 6 months, and the energy consumption that therefore how to reduce network service becomes the problem that must solve.

The network life of table 1 radio sensing network typical case application system

In radio sensing network, found through experiments the how much relevant with Anneta module opening time length of node energy consumption.Take the CC2420 Anneta module of sensors node TelosB as example, table 2 has been listed the energy consumption of CC2420 under different mode.As can be seen from Table 2, energy consumption is very large when antenna is in reception and the state of transmission, and is in idle condition and the closed condition situation, and its energy consumption is quite few.So time how to control the unlatching of sensor node antenna in radio sensing network is the popular research topic that the low energy consumption agreement relates to.

Table 2CC2420 antenna energy consumption index

In actual deployment, there is considerable radio sensing network to be positioned at unattended area, and provides energy with the battery of finite energy.Therefore, in order to keep the normal operation of system, network using " duty ratio " mechanism (Duty Cycle, duty ratio=wakeup time/whole work period) is saved energy consumption mostly.Such as at LPL(Low Power Listening, low-power is intercepted) mechanism is lower, and node is periodically slept and is waken up, and makes the node most time be in sleep state to save energy.Under LPL mechanism, the successful transmission of packet needs sending node and receiving node to be in simultaneously wake-up states, in order to realize reliably transmission, sending node must send " frame head " slightly grown than the length of one's sleep of receiving node (Preamble) before Packet Generation.The use frame head can reduce " idle waiting time " (Idle Listening) of receiving node, and the part energy consumption is transferred to sending node.But " frame head " brought more network delay.Consider network to the restriction in transmission time, original LPL mechanism can not satisfy network to the requirement of end-to-end transmission delay, and the equalization problem in the low energy consumption LPL radio sensing network between node energy consumption and the time-delay remains optimization process.

Summary of the invention

The object of the invention is to propose a kind ofly can satisfy network to delay requirement, can reduce again the consumption control method under the time-delay constraint in the radio sensing network of whole energy consumption of network.

For reaching this purpose, the present invention by the following technical solutions:

Consumption control method in a kind of radio sensing network under the time-delay constraint comprises:

When having packet to be transferred to the base station from source node in the radio sensing network, source node produces normal data packet in order to the transmission of data bag, produces pioneer's packet in order to select the node on the transmission path;

Determine the time-delay constraint of the node on the transmission path to the distance of base station according to the node on the selected transmission path;

According to the best length of one's sleep of the node on the time-delay constraint calculating transmission path of the node on the transmission path, should the best the length of one's sleep be applied to duty ratio self adaptation regulation mechanism (Duty Cycle Gearing, DC-Gear) in, obtain the transmission that new duty ratio is carried out packet;

After all packets all are transferred to the base station, work period of all nodes on the transmission path is reverted to initial condition.

Wherein, the work period of all nodes is divided into two parts on the transmission path: the length of one's sleep and wakeup time, the duty ratio of node are wakeup time/work period.

Wherein, determine that to the distance of base station the time-delay constraint of each node on the transmission path is specially according to the node on the selected transmission path: make ξ represent that network is to the time-delay needs of node, h represents the distance from the source node to the base station, ETX represents to replace using the distance of " jumping " expression, and the maximum delay time that is assigned to each jumping under the network delay constraint is:

$D_h=\mathrm{\ξ}\·\frac{{\mathrm{ETX}}_{(h,h-1)}}{{\mathrm{ETX}}_{(h,0)}}---\left(1\right)$

Wherein, ETX _{(h, h-1)}Expression is apart from the ETX between base station h hop node and the optimum neighbor node, ETX _{(h, 0)}The expression source node is to the ETX of base station.

Be specially the best length of one's sleep of wherein, calculating each node: calculate and apart from base station h-1 hop node be the length of one's sleep:

$t_{\mathrm{DC}-\mathrm{Gear}}^{(h-1)}=(D_h-D_{\mathrm{def}})\×\mathrm{PRR}+t_s---\left(2\right)$

Wherein, D _DefNode carry out DC-Gear regulate before the average delay under the default situations in the network, PRR(packet receiver rate) be the packet acceptance rate, t _sIt is the length of one's sleep of node under the acquiescence work period;

Wherein, select the node on the transmission path to be specially: pioneer's packet is selected than oneself more near the base station, and the best neighbours of link-quality are as down hop, and these nodes are joined " transmission node collection ", according to formula (2) duty ratio of selected node is carried out dynamic adjustments simultaneously.

Wherein, the node energy consumption formula is:

E _con=E _t+E _t+E _idle （3）

Wherein, E _tExpression is used for sending the energy consumption of packet, E _tTime span be directly proportional E under the different agreement with the total time length that sends frame head _tTime span different, its E _lExpression is used for the energy consumption of receive data bag, and its time length depends on the size of packet, E _IdleExpression is used for the energy consumption of idle listening, and its time length is relevant with the agreement that network uses, and hence one can see that, and node energy consumption depends primarily on time, the time of idle listening and the time of receive data bag that sends frame head in the process of transmitting.

Wherein, DC-Gear keeps the wakeup time of node constant, changes the duty ratio of node by the length of regulating the length of one's sleep.

Wherein, the DC-Gear adjustment node can cause the change of three aspects: time factor the length of one's sleep: Anneta module is opened the time, the Anneta module that are used for sending packet and is opened the time that is used for the receive data bag and the time that is used for idle listening.

Wherein, the time of transmission packet comprises: Packet Generation time (T _d) and frame head transmitting time (T _p), wherein, T _dLength depend on and the size of the packet that will send be generally fixed value, T _pLength depend on the length of one's sleep of receiving node in the work period, be used under the DC-Gear mechanism each packet of data flow from the energy consumption formula that source node sends to destination node be:

$E_t^{\left(i\right)}=I_t\·\underset{j=1}{\overset{H}{\mathrm{\Σ}}}({\tilde{T}}_{\mathrm{Pj}}^{\left(i\right)}+T_d)\·V---\left(4\right)$

Wherein, I _tThe electric current of expression sensor node Anneta module when sending data, unit is mA, and H represents source node to the distance of base station, and unit is for jumping, and V represents the operating voltage of transducer, unit is V, I data wrap in the defeated transmitting time of j jump set under the expression DC-Gear mechanism.

Wherein, the time of receive data bag comprises: the time (T that receives effective data packets _d) and be used for time of receiving unit frame head

The energy consumption formula that be used for to receive each packet that sends over from upper hop under the DC-Gear mechanism is:

$E_l^{\left(i\right)}=I_l\·\underset{j=1}{\overset{H}{\mathrm{\Σ}}}({\widetilde{\mathrm{\η}}}_j^{\left(i\right)}+T_d)\·V---\left(5\right)$

Wherein, I _lThe electric current of expression sensor node Anneta module when receive data, unit is mA, and H represents source node to the distance of base station, and unit is for jumping, and V represents the operating voltage of transducer, unit is V,

Be illustrated in the time of receiving unit frame head when i data of reception wrap in the j jumping under the DC-Gear mechanism.

Wherein, the time of idle listening is: node wakes up rear when channel is intercepted, if do not listen to available information, these are intercepted and just are called idle listening so, use DC-Gear to after the sensor node duty ratio is regulated in the radio sensing network, its idle waiting time can increase, but the time of Internet Transmission effective data packets can shorten, make N data bag form data flow, after then using DC-Gear that the duty ratio of sensor node is carried out dynamic adjustments, the total energy consumption formula that all nodes are used for idle listening on the transmission path in whole data stream transmitting process is:

${\tilde{E}}_{\mathrm{idle}}=I_l\·\left\{\right[\tilde{L}-\underset{i=1}{\overset{N}{\mathrm{\Σ}}}(\frac{{\tilde{E}}_l^{\left(i\right)}}{I_t}+\frac{{\tilde{E}}_l^{\left(i\right)}}{I_l})]\·\frac{t_l}{\tilde{T}}+\mathrm{\ΔL}\·\frac{t_l}{T}\·V---\left(6\right)$

Wherein, Δ L represents time of using DC-Gear to fulfil ahead of schedule,

Expression uses DC-Gear to finish used total time of data stream transmitting, I _lThe electric current of expression sensor node Anneta module when receive data, unit is mA, N represents the number of packet in the data flow,

With

Represent respectively the time

The interior summation that from the source node to the base station, sends i packet and receive i packet energy consumption.

Beneficial effect of the present invention is: the consumption control method in a kind of radio sensing network under the time-delay constraint, when having packet to be transferred to the base station from source node in the radio sensing network, source node produces normal data packet in order to the transmission of data bag, produces pioneer's packet in order to select the node on the transmission path; Determine the time-delay constraint of the node on the transmission path to the distance of base station according to the node on the selected transmission path; Should the best be applied in the duty ratio self adaptation regulation mechanism the best length of one's sleep according to the node on the transmission path is calculated in the time-delay constraint of the node on the transmission path length of one's sleep, obtains the transmission that new duty ratio is carried out packet; After all packets all are transferred to the base station, the work period of all nodes on the transmission path is reverted to initial condition, the present invention is optimized the equalization problem between node energy consumption in the low-consumption wireless sensing network and the time-delay, satisfying under the prerequisite of radio sensing network to the transmission delay constraint, reduce to greatest extent the energy consumption of radio sensing network, and prolonged the useful life of radio sensing network.

Description of drawings

Fig. 1 is the inventive method flow chart

Fig. 2 is node sleep time and the graph of a relation of saving energy consumption

Fig. 3 is the work schematic diagram that X-MAC and LPL use different frame heads

Fig. 4 is the work schematic diagram that DC-Gear and X-MAC use different frame heads

Embodiment

Further specify technical scheme of the present invention below in conjunction with Fig. 1-Fig. 4 and by embodiment.

Consumption control method in a kind of radio sensing network under the time-delay constraint comprises:

When having packet to be transferred to the base station from source node in the radio sensing network, source node produces normal data packet in order to the transmission of data bag, produces pioneer's packet in order to select the node on the transmission path;

Determine the time-delay constraint of the node on the transmission path to the distance of base station according to the node on the selected transmission path;

Should the best be applied in the DC-Gear mechanism the best length of one's sleep according to the node on the transmission path is calculated in the time-delay constraint of the node on the transmission path length of one's sleep, obtains the transmission that new duty ratio is carried out packet;

After all packets all are transferred to the base station, work period of all nodes on the transmission path is reverted to initial condition.

In the present embodiment, the work period of all nodes is divided into two parts on the transmission path: the length of one's sleep and wakeup time, the duty ratio of node is wakeup time/work period, conventional understanding, the duty ratio that improves node can increase the ratio of node wakeup time in the work period, its result will be the raising of network energy consumption, but the statistical analysis to the GreenOrbs system data is found, in the radio sensing network under using LPL mechanism, the node duty ratio is suitably improved, not only total energy consumption can not increase in some cases, reduces on the contrary.

Under the network delay constraint, save schematic diagram, abscissa T among the figure by the energy consumption that obtains in the adjustment node duty ratio situation as shown in Figure 2 _sThe initial length of one's sleep of representation node; d ₁, d ₂Represent respectively network to two kinds of constraints of transmission delay; O_T _sThe best length of one's sleep that representative needs node to use when reaching energy consumption minimized.Ordinate represents compare the situation that the network energy consumption is saved after " duty ratio " adjusting with default situations.Can find by Fig. 2, " duty ratio " that can regulate working node in network realizes the energy consumption saving.In practical operation, can be divided into two kinds of situations to the needs of delaying time according to network and carry out: the first situation is that network is positioned at d to the constraint of delaying time _lThe position can not realize that energy consumption saves by regulating " duty ratio ", and at this moment, network can only be sacrificed energy consumption and be satisfied constraints to delaying time; The second situation is that network is positioned at d to the constraint of delaying time ₂Adjustment node " duty ratio " can be passed through to O_T in the position _sMinimizing of network energy consumption realized in the position.

In the present embodiment, determine that to the distance of base station the time-delay constraint of each node on the transmission path is specially according to the node on the selected transmission path: make ξ represent that network is to the time-delay needs of node, h represents the distance from the source node to the base station, ETX represents to replace using the distance of " jumping " expression, and the maximum delay time that is assigned to each jumping under the network delay constraint is:

$D_h=\mathrm{\ξ}\·\frac{{\mathrm{ETX}}_{(h,h-1)}}{{\mathrm{ETX}}_{(h,0)}}---\left(1\right)$

Wherein, ETX _{(h, h-l)}Expression is apart from the ETX between base station h hop node and the optimum neighbor node, ETX _{(h, 0)}The expression source node is to the ETX of base station, in time-delay restricted type radio sensing network, carry the packet of effective information must be before finishing confinement time data packet transmission to the base station, yet, each node of network is not identical to the distance of base station, therefore is necessary to determine to the distance of base station according to each node the time-delay constraint of each node on the transmission path.

In the present embodiment, jump the linear module that refers to path in the network.

Be specially the best length of one's sleep of in the present embodiment, calculating each node: calculate and apart from base station h-1 hop node be the length of one's sleep:

$t_{\mathrm{DC}-\mathrm{Gear}}^{(h-1)}=(D_h-D_{\mathrm{def}})\×\mathrm{PRR}+t_s---\left(2\right)$

Wherein, D _DefBe that node is carrying out DC-Gear(Duty Cycle Gearing, the duty ratio self adaptation is regulated) regulate before the average delay under the default situations in the network, PRR(packet receiver rate) be the packet acceptance rate, t _sIt is the length of one's sleep of node under the acquiescence work period;

In the present embodiment, select the node on the transmission path to be specially: when having data flow to be transferred to the base station from source node in the network, source node can produce two kinds of bags: pioneer's packet and normal data packet, pioneer's packet is produced by source node behind perception events, is used for selecting the node of transmission path; Pioneer's packet contains two characteristics: the one, contain the order that down hop is optimized operation, and have higher operating right; The one, be the path of the transmission of follow-up normal data packet selection from the source node to the base station.In the network each sensor node know and neighbor node between link-quality and neighbor node to the distance of base station, therefore pioneer's packet is selected than oneself more near the base station, and the best neighbours of link-quality are as down hop, and these nodes are joined " transmission node collection ", simultaneously according to formula (2) duty ratio of alternative node is carried out dynamic adjustments, the packet of pioneer's packet back can be transmitted to the base station by source node according to the selected transmission path of pioneer's node, to the last arrives the base station.

In the present embodiment, node must send a frame head (Preamble) slightly longer than the length of one's sleep of receiving node before sending packet, use frame head can reduce the idle listening time (IdleListening) of receiving node and the part energy consumption is transferred to sending node, but frame head has brought more network delay, consider the restriction of network to the transmission time, original LPL mechanism can not satisfy network to the requirement of end-to-end transmission delay, therefore is necessary the equalization problem between node energy consumption in the low-power consumption LPL sensing network and the time-delay is optimized.

In the present embodiment, the node energy consumption formula is:

E _con=E _t+E _t+E _idle （3）

Wherein, E _tExpression is used for sending the energy consumption of packet, E _tTime span be directly proportional E under the different agreement with the total time length that sends frame head _tTime span different, its E _lExpression is used for the energy consumption of receive data bag, and its time length depends on the size of packet, E _IdleExpression is used for the energy consumption of idle listening, its time length is relevant with the agreement that network uses, hence one can see that, and node energy consumption depends primarily on time, the time of idle listening and the time of receive data bag that sends frame head in the process of transmitting, and Fig. 3 has provided LPL and the difference of X-MAC on the operating time.Find E by research _tTo affect E _ConPrincipal element, by to E _IdleCarry out the adjusting of lightweight, E _tCan significantly decrease.Affected by this, E _ConAlso have a considerable saving, this phenomenon is called " few sleep, but province's energy consumption ".Based on this phenomenon, in carrying out data transmission procedure, DC-Gear is by the energy consumption that reduces whole network the length of one's sleep of part of nodes in the dynamic minimizing network.

The DC-Gear that the present invention proposes is under LPL mechanism, keep the wakeup time of node constant, change the duty ratio of node by the length of regulating the length of one's sleep, thereby realize saving to greatest extent the network energy consumption and prolonging network useful life satisfying under the prerequisite of network to the transmission delay constraint.

In the present embodiment, the DC-Gear adjustment node can cause the change of three aspects: time factor the length of one's sleep: Anneta module is opened the time, the Anneta module that are used for sending packet and is opened the time that is used for the receive data bag and the time that is used for idle listening.

In the present embodiment, the time of transmission packet comprises: Packet Generation time (T _d) and frame head transmitting time (T _p), wherein, T _dLength depend on and the size of the packet that will send be generally fixed value, T _pLength depend on the length of one's sleep of receiving node in the work period, be used under the DC-Gear mechanism each packet of data flow from the energy consumption formula that source node sends to destination node be:

$E_t^{\left(i\right)}=I_t\·\underset{j=1}{\overset{H}{\mathrm{\Σ}}}({\tilde{T}}_{\mathrm{Pj}}^{\left(i\right)}+T_d)\·V---\left(4\right)$

Wherein, I _tThe electric current of expression sensor node Anneta module when sending data, unit is mA, and H represents source node to the distance of base station, and unit is for jumping, and V represents the operating voltage of transducer, unit is V,

I data wrap in the defeated transmitting time of j jump set under the expression DC-Gear mechanism.

As shown in Figure 4, under the X-MAC agreement for each packet with data flow from the energy consumption formula that source node sends to destination node be:

$E_t^{\left(i\right)}=I_t\·\underset{j=1}{\overset{H}{\mathrm{\Σ}}}(T_{\mathrm{Pj}}^{\left(i\right)}+T_d)\·V---\left(7\right)$

Wherein, I _tThe electric current of expression sensor node Anneta module when sending data, unit is mA, and H represents source node to the distance of base station, and unit is for jumping, and V represents the operating voltage of transducer, unit is V, T _Pj ⁽ⁱ⁾I data wrap in the defeated transmitting time of j jump set under the expression LPL mechanism.

Can get the DC-Gear energy consumption of comparing with X-MAC when sending packet by formula (4) and (7) saves formula and is:

$\mathrm{\Δ}{E}_t^{\left(i\right)}=I_t\·\underset{j=1}{\overset{H}{\mathrm{\Σ}}}(T_{\mathrm{Pj}}^{\left(i\right)}-{\tilde{T}}_{\mathrm{Pj}}^{\left(i\right)})\·V---\left(8\right)$

In the present embodiment, the time of receive data bag comprises: the time (T that receives effective data packets _d) and be used for time of receiving unit frame head The energy consumption formula that be used for to receive each packet that sends over from upper hop under the DC-Gear mechanism is:

$E_l^{\left(i\right)}=I_l\·\underset{j=1}{\overset{H}{\mathrm{\Σ}}}({\widetilde{\mathrm{\η}}}_j^{\left(i\right)}+T_d)\·V---\left(5\right)$

Wherein, I _lThe electric current of expression sensor node Anneta module when receive data, unit is mA, and H represents source node to the distance of base station, and unit is for jumping, and V represents the operating voltage of transducer, unit is V, Be illustrated in the time of receiving unit frame head when i data of reception wrap in the j jumping under the DC-Gear mechanism.

The energy consumption formula that be used for to receive each packet that sends over from upper hop under the X-MAC agreement is:

$E_l^{\left(i\right)}=I_l\·\underset{j=1}{\overset{H}{\mathrm{\Σ}}}({\mathrm{\η}}_j^{\left(i\right)}+T_d)\·V---\left(9\right)$

Wherein, I _lThe electric current of expression sensor node Anneta module when receive data, unit is mA, and H represents source node to the distance of base station, and unit is for jumping, and V represents the operating voltage of transducer, unit is V,

Be illustrated in the time of receiving unit frame head when i data of reception wrap in the j jumping under the X-MAC mechanism.Why Fig. 4 has illustrated

It is the time of receiving unit frame head: in the X-MAC situation, receiving node intercepts channel time after waking up and sending node frame head transmitting time has two kinds of situations, a kind of is after receiving node is waken up, just receive a frame head that is sent to oneself, then carry out the ACK answer and keep wake-up states to receive following effective data packets, this moment It is the time span of a complete frame head; Another kind of situation is to listen to after waking up to have frame head but be not complete frame head, then keeps wake-up states to wait for next frame head, makes corresponding ACK again and replys and receive subsequently packet.

Energy consumption is saved formula and is in the time of can being got DC-Gear and compared the receive data bag with X-MAC by formula (5) and (9):

$\mathrm{\Δ}{E}_l=I_l\·\underset{j=1}{\overset{H}{\mathrm{\Σ}}}({\mathrm{\η}}_j^{\left(i\right)}-{\tilde{T}}_j^{\left(i\right)})\·V---\left(10\right)$

In the present embodiment, the time of idle listening is: node wakes up rear when channel is intercepted, if do not listen to available information, these are intercepted and just are called idle listening so, use DC-Gear to after the sensor node duty ratio is regulated in the radio sensing network, its idle waiting time can increase, but the time of Internet Transmission effective data packets can shorten, for relatively DC-Gear and two kinds of machine-processed lower nodes of X-MAC in the difference of energy consumption aspect the idle listening, the total time as a comparison total time that is transmitted data flow (N packet) under the X-MAC mechanism and consumes.Make L represent to use and transfer N needed total time of packet, its computational methods such as formula (11) under the X-MAC mechanism:

L=(N-1)·T+b/B （11）

Wherein, b represents the load of each packet, unit is bit, T is that source node produces the time interval between two packets, B represents that sensor node is at the current duty network throughput under the current channel circumstance when, its data are subjected to change such as the difference of network environment, sensor node voltage etc., such as formula (12):

$B=B_0\·\left(\frac{t_l-\mathrm{\δ}}{T}\right)---\left(12\right)$

Wherein, δ represents the operation delay of sensor node self, comprises in the time-delay of processing time-delay, the transmit queue in the buffer memory, data transmission procedure of CPU causing the time-delay of keeping out of the way formation etc., B because channel is busy ₀Be the network throughput during full load running (duty ratio is 1) under the current network environment, unit is bps.

The job specification of the whole operating time of radio sensing network by Anneta module is divided into four classes: the time of the bag that is used for transmitting and receive data, be used for the sending and receiving frame head time, be used for the time of idle listening and be used for time of sleep in order to save energy consumption, the timer node that wherein is used for sleep is consumed energy not.Therefore, transmit in the time period in the whole data flow procedure at L, the total energy consumption that node is used for intercepting in the space on the transmission path can be used formula (13) expression:

$E_{\mathrm{idle}}=I_l\·[L-\underset{i=1}{\overset{N}{\mathrm{\Σ}}}(\frac{E_t^{\left(i\right)}}{I_t}+\frac{E_l^{\left(i\right)}}{I_l})]\·\frac{t_1}{T}\·V---\left(13\right)$

I wherein _lThe electric current of expression sensor node Anneta module when sending packet, unit is mA; N represents total number of packet in the data flow;

With

Represent respectively from the source node to the base station, to send in the time L i packet and receive i the catabiotic summation of packet; T represents a work period; V represents the operating voltage (V) of sensor node.

Can find out such as Fig. 4, the data flow of transmitting N data bag composition is using the deadline in the DC-Gear situation to shift to an earlier date than use X-MAC.Make Δ L represent the time of using DC-Gear to fulfil ahead of schedule,

Expression uses DC-Gear to finish needed total time of data stream transmitting, can obtain formula (14):

$L=\tilde{L}+\mathrm{\ΔL}---\left(14\right)$

After using DC-Gear that the duty ratio of sensor node is carried out dynamic adjustments, the total energy consumption formula that all nodes are used for idle listening on the transmission path in whole data stream transmitting process is:

${\tilde{E}}_{\mathrm{idle}}=I_l\·\left\{\right[\tilde{L}-\underset{i=1}{\overset{N}{\mathrm{\Σ}}}(\frac{{\tilde{E}}_l^{\left(i\right)}}{I_t}+\frac{{\tilde{E}}_l^{\left(i\right)}}{I_l})]\·\frac{t_l}{\tilde{T}}+\mathrm{\ΔL}\·\frac{t_l}{T}\·V---\left(6\right)$

Wherein, Δ L represents time of using DC-Gear to fulfil ahead of schedule,

Expression uses DC-Gear to finish used total time of data stream transmitting, I _tThe electric current of expression sensor node Anneta module when receive data, unit is mA, N represents the number of packet in the data flow,

With

Represent respectively the time

The interior summation that from the source node to the base station, sends i packet and receive i packet energy consumption.

Can obtain in the whole process of data stream transmitting by upper surface analysis, use under X-MAC and two kinds of different mechanisms of DC-Gear on the transmission path total energy consumption of all nodes as shown in Equation (15).

$\left\{\begin{array}{c}{E}_{X-\mathrm{MAC}}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}(E_t^{\left(i\right)}+E_l^{\left(i\right)})+E_{\mathrm{idle}}\\ E_{\mathrm{DC}-\mathrm{Gear}}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}({\tilde{E}}_t^{\left(i\right)}+{\tilde{E}}_l^{\left(i\right)})+{\tilde{E}}_{\mathrm{idle}}\end{array}\right.---\left(15\right)$

Make E _SaveExpression is compared the energy of DC-Gear and is saved with X-MAC, formula (16) is then arranged:

$E_{\mathrm{save}}=E_{X-\mathrm{MAC}}-E_{\mathrm{DC}-\mathrm{Gear}}=I_l\·\left\{\begin{array}{c}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\left[\right(\frac{{\tilde{E}}_t^{\left(i\right)}}{I_t}+\frac{{\tilde{E}}_l^{\left(i\right)}}{I_l})\·\frac{t_1}{\tilde{T}}]-\\ (\frac{E_t^{\left(i\right)}}{I_t}+\frac{E_l^{\left(i\right)}}{I_l})\·\frac{t_1}{T}+\frac{E_t^{\left(i\right)}-{\tilde{E}}_t^{\left(i\right)}}{I_l}\\ -\mathrm{\ΔL}\·\frac{t_1}{T}\·V+(L\·\frac{t_1}{T}-\tilde{L}\·\frac{t_1}{\tilde{T}})\end{array}\right\}---\left(16\right)$

The above only is the specific embodiment of the present invention, and these are described just in order to explain principle of the present invention, and can not be interpreted as by any way limiting the scope of the invention.Based on explanation herein, those skilled in the art does not need to pay performing creative labour can associate other embodiment of the present invention, and these modes all will fall within protection scope of the present invention.

Claims (10)

1. the consumption control method under the time-delay constraint in the radio sensing network is characterized in that, comprising:

When having packet to be transferred to the base station from source node in the radio sensing network, source node produces normal data packet in order to the transmission of data bag, produces pioneer's packet in order to select the node on the transmission path;

Determine the time-delay constraint of the node on the transmission path to the distance of base station according to the node on the selected transmission path;

Should the best be applied in the duty ratio self adaptation regulation mechanism the best length of one's sleep according to the node on the transmission path is calculated in the time-delay constraint of the node on the transmission path length of one's sleep, obtains the transmission that new duty ratio is carried out packet;

After all packets all are transferred to the base station, work period of all nodes on the transmission path is reverted to initial condition.

2. method according to claim 1 is characterized in that, the work period of all nodes is divided into two parts on the described transmission path: the length of one's sleep and wakeup time, the duty ratio of node are wakeup time/work period.

3. method according to claim 1, it is characterized in that, describedly determine that to the distance of base station the time-delay constraint of each node on the transmission path is specially according to the node on the selected transmission path: make ξ represent that network is to the time-delay needs of node, h represents the distance from the source node to the base station, ETX represents to replace using the distance of " jumping " expression, and the maximum delay time that is assigned to each jumping under the network delay constraint is:

Wherein, ETX _{(h, h-1)}Expression is apart from the ETX between base station h hop node and the optimum neighbor node, ETX _{(h, 0)}The expression source node is to the ETX of base station.

4. method according to claim 1 is characterized in that, be specially the best length of one's sleep of the node on the described calculating transmission path: calculating apart from base station h-1 hop node is the length of one's sleep:

Wherein, D _DefNode carry out duty ratio self adaptation regulation mechanism regulate before the average delay under the default situations in the network, PRR is the packet acceptance rate, t _sIt is the length of one's sleep of node under the acquiescence work period.

5. method according to claim 4, it is characterized in that, node on the described selection transmission path is specially: pioneer's packet is selected than oneself more near the base station, and the best neighbours of link-quality are as down hop, and these nodes are joined " transmission node collection ", according to formula (2) duty ratio of selected node is carried out dynamic adjustments simultaneously.

6. method according to claim 1 is characterized in that, the energy consumption formula of the node on the described transmission path is:

E _con=E _t+E _l+E _idle （3）

Wherein, E _tExpression is used for sending the energy consumption of packet, E _tTime span be directly proportional E under the different agreement with the total time length that sends frame head _tTime span different, its E _lExpression is used for the energy consumption of receive data bag, and its time length depends on the size of packet, E _IdleExpression is used for the energy consumption of idle listening, and its time length is relevant with the agreement that network uses.

7. method according to claim 1, it is characterized in that, described should the best the length of one's sleep be applied to the change that can cause the three aspects: time factor in the duty ratio self adaptation regulation mechanism: be used for sending packet time, be used for the time of receive data bag and the time that is used for idle listening.

8. method according to claim 7 is characterized in that, the time of described transmission packet comprises: Packet Generation time (T _d) and frame head transmitting time (T _p), wherein, T _dLength depend on and the size of the packet that will send be fixed value, T _pLength depend on the length of one's sleep of receiving node in the work period, be used under the DC-Gear mechanism each packet of data flow from the energy consumption formula that source node sends to destination node be:

Wherein, I _tThe electric current of expression sensor node Anneta module when sending data, unit is mA, and H represents source node to the distance of base station, and unit is for jumping, and V represents the operating voltage of transducer, unit is V,

I data wrap in the defeated transmitting time of j jump set under the expression DC-Gear mechanism.

9. method according to claim 7 is characterized in that, the time of described receive data bag comprises: the time (T that receives effective data packets _d) and be used for time of receiving unit frame head

The energy consumption formula that be used for to receive each packet that sends over from upper hop under the duty ratio self adaptation regulation mechanism is:

Wherein, I _lThe electric current of expression sensor node Anneta module when receive data, unit is mA, and H represents source node to the distance of base station, and unit is for jumping, and V represents the operating voltage of transducer, unit is V,

Be illustrated in the time of receiving unit frame head when i data of reception wrap in the j jumping under the duty ratio self adaptation regulation mechanism.

10. method according to claim 7, it is characterized in that, the time of described idle listening is: node wakes up rear when channel is intercepted, if do not listen to available information, these are intercepted and just are called idle listening so, use duty ratio self adaptation regulation mechanism to after the sensor node duty ratio is regulated in the radio sensing network, its idle waiting time can increase, but the time of Internet Transmission effective data packets can shorten, make N data bag form data flow, after then using duty ratio self adaptation regulation mechanism that the duty ratio of sensor node is carried out dynamic adjustments, the total energy consumption formula that all nodes are used for idle listening on the transmission path in whole data stream transmitting process is:

Wherein, Δ L represents time of using duty ratio self adaptation regulation mechanism to fulfil ahead of schedule,

Expression uses duty ratio self adaptation regulation mechanism to finish used total time of data stream transmitting, I _lThe electric current of expression node Anneta module when receive data, unit is mA, N represents the number of packet in the data flow,

With Represent respectively the time

The interior summation that from the source node to the base station, sends i packet and receive i packet energy consumption.

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