CN103237332B - Energy-saving routing method for underwater sensor network on basis of vector forwarding - Google Patents

Abstract

The invention provides an energy-saving routing method for an underwater sensor network on the basis of vector forwarding. The energy-saving routing method includes computing distances from nodes to previous hop nodes recorded in data packets and angles of arrival of the previous hop nodes when the nodes receive the data packets, and judging whether the distances and the angles of arrival are within ranges of radiuses of forwarding channels or not; computing the distance from each node to projection of the node on a routing vector from a corresponding source node to a corresponding destination node and an included angle between a vector from each previous hop node to a corresponding destination node and a vector from the previous hop node to the corresponding node; computing forwarding coefficients; enabling the nodes to hold the data packets and wait for certain periods, and computing the corresponding forward coefficients relative to a plurality of corresponding nodes again whenever a certain node receives the corresponding data packet from the corresponding nodes during waiting; and broadcasting within the forwarding radiuses if repeated packets are not received during waiting, and forwarding the data packets. The energy-saving routing method for the underwater dynamic network has the advantages that the routing energy consumption of the network can be effectively saved, the energy consumption of the total network can be balanced, network cavities are prevented, and accordingly the service life of the network is greatly prolonged.

Description

A kind of underwater sensor network energy-saving routing method forwarded based on vector

Technical field

The present invention relates to underwater sensor network communication technical field, is specifically the method for the saving routing procedure energy ezpenditure that a kind of routing layer of network under water forwards based on vector.

Background technology

Under water network environment and land network the network interconnection with to communicate etc. in although there is certain similitude, in a lot of, have larger difference.Network causes network traffic conditions to be different from land due to the impact of following factor under water: electromagnetic wave is bandwidth critical constraints in long propagation under water, only has 30-3000HZ, need higher transmitting power and through-put power, and transmission delay is large simultaneously; It is impaired that multipath effect and decay make channel under water be very easy to; The extreme feature of channel causes the high error rate of Signal transmissions under water; Underwater sensor easily lost efficacy due to factors such as water body corrosion; The difficulty of charging or replacing battery makes transducer life span limited, thus limits the life span of whole network.

In addition, the particularity of underwater environment, makes underwater sensor network also have following feature: extensive, self-organizing, dynamic.Be mainly reflected in waters wide scope on a large scale, ocean area is comparatively large, and which region unknown can produce significant information, so need to lay sensor node on a large scale, to cover region large as far as possible, thus obtains useful information widest in area.Self-organizing is then because underwater sensor is not most of node of picture land, the adjustment of attendant can be obtained when needing, the value of information more needing to judge voluntarily positional information and collect, in addition, more to automatically configure and manage, rely on the topological structure forwarding Routing Protocol and autonomous formation to form underwater transmission network system.Topological structure neither be unalterable, the movement of Marine Weather situation, mankind's activity and sensor node and lost efficacy and all may cause the dynamic of underwater sensor network, and topological structure is constantly changed.

The not easily attainability of underwater environment makes sensor node can not obtain electricity supply or battery altering in time, and the decay of underwater acoustic channel and multipath effect make transmission and Received signal strength need relatively high power, therefore, the power-saving technology of underwater sensor network studies the emphasis of network under water.

The existing Routing Protocol under water forwarded based on vector often can not consider position, motion and energy three factors for the network under water carrying out forwarding, comprehensive not during selection route: repeatedly to select the node with advantageous position to forward, make respective regions individual node because repeatedly use and depleted of energy, cause the whole network at the routing failure of these node locations, formation network cavity, causes network to be paralysed too early.

Summary of the invention

The present invention is intended to the above-mentioned deficiency overcoming prior art, provides a kind of underwater sensor network energy-saving routing method that can consider node location information, movable information and energy information when network carries out Route Selection under water.In order to achieve the above object, the present invention adopts following technical scheme:

A kind of underwater sensor network energy-saving routing method forwarded based on vector, each packet of the method transmission is with sending node, destination node and previous dive node location information, forward-path is determined by the vector of source node to destination node, and the method comprises the following aspects:

1) movement velocity be the node of v when receiving packet, calculate distance m and the angle of arrival of the previous dive node recorded in itself and packet, judge whether within forwarding pipe radius s; If so, then computing node and its in source-destination node route vector the distance l of upper projection, and previous dive-destination node vector with previous dive-this knot vector angle β; Otherwise, abandon;

2) adopt formula (1) to calculate and forward coefficient δ:

$\mathrm{\δ}=v*0.1+{(1-\frac{\mathrm{energy}}{\mathrm{initialenergy}})}^N+\left(\frac{l}{s}\right)+\left(\frac{r-m*\cos \mathrm{\β}}{r}\right)---\left(1\right)$

In formula, N is the natural number that value is greater than 0, and r is for forwarding radius, and energy is node current remaining, and initialenergy is node primary power;

3) the node bag that holds data waits for a period of time T _adaptationif node repeatedly receives this packet from multiple node at waiting time, often receive once, it can recalculate oneself forwarding coefficient relative to these nodes, and remembering that initial previous dive node forwards coefficient is δ ₀, afterwards be respectively δ ₁, δ ₂..., δ _nif met n is the nodes except issuing this node identical data packet after initial previous dive node, δ _ca predefined constant, 0≤δ _c≤ 3, node just forwards this packet, otherwise, abandoned; If do not receive duplicate packages etc. biding one's time, then broadcast in forwarding radius r, continue forwarding data bag.

Preferably, when adopting formula (1) to calculate forwarding coefficient, l, s, m and angle β judge based on present node positional information, and v judges based on joint movements information; N can get different value according to practical application, if network is high to energy-conservation requirement, N gets 1, if high to the requirement forwarding success rate, can get 2,3 or higher; Stand-by period is determined according to formula (2):

$T_{\mathrm{adaptation}}=\sqrt{\mathrm{\δ}}*T_{\mathrm{delay}}+\left(\frac{r-m}{v_0}\right)---\left(2\right)$

Wherein, T _delaythe maximum delay of a cosine definition, v ₀the transmission rate of underwater sound signal.

Compared with conventional method, node average residual energy of the present invention enlarges markedly; Residue energy of node variance reduces; Forwarding success rate reduces few, can ignore, do not affect practical application, can be effectively balanced node energy consumption, make in node routing procedure, to consider position and dump energy information, to whether being applicable to forwarding evaluation, correct total calculation oneself is in all priority held in identical data packet node, the node of energy abundance preferentially forwards, thus balance energy ezpenditure, extend network lifetime, achieve energy-conservation object, and have good adaptability for the topological diagram of dynamic change.

Accompanying drawing explanation

Fig. 1 adopts underwater sensor network schematic diagram of the present invention.

Fig. 2 is route flow chart of the present invention.

Embodiment

The energy-saving routing method that underwater sensor network routing layer provided by the invention forwards based on vector, the energy ezpenditure in the past forwarding route technology based on vector is optimized by introducing capacity factor, in routing procedure, consider position, motion and energy ezpenditure three factors, more, that positional information the is more excellent nodes of dump energy are selected preferentially to forward, contribute to node energy equilibrium like this to consume, avoid respective nodes repeatedly to use, depleted of energy was so that lost efficacy.Scheme is as follows:

1. the vector from source node to destination node determines that forwards a cylindrical region, and there is one fixed width s in this region.Directivity in repeating process is from source node towards the direction near destination node all the time, can not return transmission.Previous dive carries out with the forms of broadcasting this forwarding, not only a node receives packet, the distance m of the previous dive node recorded in all node calculate receiving this bag itself and packet and the angle of arrival (the angle of arrival, AOA, the angle of arrival is the angle between the direction line of packet arrival and node place horizontal plane).

2. sensor node judges that whether oneself distance repeating vector is enough near, if not, directly abandon this packet, thus unnecessary forwarding step can be saved, save energy.If enough near, then the preparation carrying out forwarding of having an opportunity.In underwater sound communication network, usually all the information that sensor node collects is sent to Chuan Ji receiving station (SINK), by SINK, analyzing and processing is carried out to data.

3. sensor node calculate with its in source-destination node route vector the distance l of upper projection, and previous dive-destination node vector with previous dive-this knot vector angle β.Adopt formula (1) to calculate and forward coefficient δ.Effectively avoid the node energy excessive loss with position advantage, make position deviation little, movement velocity is little and the node with enough energy can participate in forwarding data bag, reasonable equalizing network energy consumption.

4. use waiting mechanism before forwarding, the node bag that holds data waits for a period of time T _adaptation.Formula (2) is adopted to calculate stand-by period T _adaptation.Node is evaluated oneself in the adaptability of numerous neighbor node repeating data bag again at waiting time.The node that time delay and speed positive correlation make movement velocity large does not participate in forwarding, and reduces consequent packet loss.N value can be chosen according to different situations, if network is high to energy-conservation requirement, N gets 1, if success rate is high can get 2 or higher to forwarding.The energy added in formula (1) one is being less than 0.5, and speed term is less than 0.3, and location entries, between [0,3], does not cause the impact of essence, and is acceptable suitably to increase the balancing energy that time delay is cost on time delay.

5., when residue energy of node is larger, forward coefficient δ less, this node can more early forward, otherwise, then to wait for.If waiting time receives the identical packet that other nodes are sent out again, then again calculate and forward coefficient δ, finally judge whether to forward.In reality, if node receives the packet that two or more repeats waiting to bide one's time, then this node will by data packet discarding.

6. node judges oneself priority in all neighbor nodes, if be the highest, then broadcasts to forward radius r, uses identical judgement priority approach to continue forwarding data bag.

So just can effectively save forwarding energy ezpenditure, equalizing network energy, greatly extends network lifetime.

As follows see Fig. 1 and Fig. 2 concrete scheme of the present invention.

(1) in each packet, three bands of position are had: OP, TP, FP, i.e. the coordinate system of sending node, destination node and previous dive node.Eachly include a RANGE region, when packet arrives the RANGE region at destination node place, just in this region, carry out inundation.Underwater sensor network initiates route requests, has two kinds of modes: a kind of Shi Chuan base receiving station SINK initiates; A kind of be route source initiate.Wherein, the mode that Chuan Ji receiving station SINK initiates has two kinds: location-based request and position are independently asked.The former Shi Chuan base receiving station SINK only wants to understand the data message that certain particular range inner sensor node collects, so it is location-based.To be SINK be interested in certain type or with the data of some information the latter, and go for these information, then no matter which node has, and the node no matter having these information where, all will obtain this information.

(2) node is with forms of broadcasting forwarding data bag, and the vector from source node to destination node determines a Relay Region, and this region is cylindrical, and width is s.The direction of repeating process is all the time from source node to destination node direction.Under water in network model for the purpose of SINK point node.The sensor node receiving this packet calculates distance m and the angle of arrival (AOA) of the previous dive node recorded in itself and packet.Sensor node judges whether oneself is positioned at cylindrical region, if not, abandon this packet, economize the forwarding step of de-redundancy, save energy.If in region, the preparation carrying out forwarding of having an opportunity.In underwater sound communication network, usually the information that sensor node collects is sent to Chuan Ji receiving station SINK, by SINK, analyzing and processing is carried out to data.

(3) sensor node calculate with its in source-destination node route vector the distance l of upper projection, and previous dive-destination node vector with previous dive-this knot vector angle β, obtain relevant position information, then adopt formula (1) to calculate to forward coefficient δ.

(4) if certain node to be on repeating vector and at the broadcasting area edge of previous dive forward node, then this node is called as optimal node, its position is called as optimum position, after considering motion and capacity factor, effectively prevent the node energy excessive loss that this type of has position advantage.Select can not repeatedly select this node during route, consume its energy excessively, then consider the node of other positions, even if position deviation is not very large, but also can forward when there is enough energy and appropriate motion speed, rational equalizing network energy consumption, make network energy consumption even.

(5) use forward before waiting mechanism, the node bag that holds data waits for a period of time T _adaptation.Formula (2) is adopted to calculate stand-by period T _adaptation.If waiting time receives the identical data that other nodes are sent out again, then again calculate and forward coefficient δ, finally judge whether to forward.When the minimum forwarding factor is less than threshold value shi Jixu forwarding data bag.

Use Aqua-Sim under water Network Simulation Software verify based on underwater sensor network routing layer, arrange environment facies with under, the method node average residual energy compared with conventional method enlarges markedly; Residue energy of node variance reduces; Forwarding success rate reduces few, can ignore, not affect practical application.Node energy consumption that proof the method is effectively balanced, make in node routing procedure, to consider position and dump energy information, to whether being applicable to forwarding evaluation, correct total calculation oneself is in all priority held in identical data packet node, the node of energy abundance preferentially forwards, thus balances energy ezpenditure, extends network lifetime, achieve energy-conservation object, and have good adaptability for the topological diagram of dynamic change.

Claims (4)

1. the underwater sensor network energy-saving routing method forwarded based on vector, each packet of the method transmission is with sending node, destination node and previous dive node location information, forward-path is determined by the vector of source node to destination node, and the method comprises the following aspects:

1) movement velocity be the node of v when receiving packet, calculate distance m and the angle of arrival of the previous dive node recorded in itself and packet, judge whether within forwarding pipe radius s; If so, then computing node and its in source-destination node route vector the distance l of upper projection, and previous dive-destination node vector with previous dive-this knot vector angle β; Otherwise, abandon;

2) adopt formula (1) to calculate and forward coefficient δ:

$\mathrm{\δ}=v*0.1+{(1-\frac{\mathrm{energy}}{\mathrm{initialenergy}})}^N+\left(\frac{l}{s}\right)+\left(\frac{r-m*\cos \mathrm{\β}}{r}\right)---\left(1\right)$

In formula, N is the natural number that value is greater than 0, and r is for forwarding radius, and energy is node current remaining, and initialenergy is node primary power;

3) the node bag that holds data waits for a period of time T _adaptationif node repeatedly receives this packet from multiple node at waiting time, often receive once, recalculate the forwarding coefficient of node relative to these sending nodes itself, remembering that initial previous dive node forwards coefficient is δ ₀, afterwards be respectively δ ₁, δ ₂..., δ _nif met n is the nodes except issuing this node identical data packet after initial previous dive node, δ _ca predefined constant, 0≤δ _c≤ 3, node just forwards this packet, otherwise, abandoned; If do not receive duplicate packages etc. biding one's time, then broadcast in forwarding radius r, continue forwarding data bag.

2. method as claimed in claim 1, is characterized in that, when adopting formula (1) to calculate forwarding coefficient, l, s, m and angle β judge based on present node positional information, and v judges based on joint movements information.

3. method as claimed in claim 1, it is characterized in that, N can get different value according to practical application, if network is high to energy-conservation requirement, N gets 1, if high to the requirement forwarding success rate, can get 2,3 or higher.

4. method as claimed in claim 1, it is characterized in that, the stand-by period is determined according to formula (2):

$T_{\mathrm{adaptatiom}}=\sqrt{\mathrm{\δ}}*T_{\mathrm{delay}}+\left(\frac{r-m}{v_0}\right)---\left(2\right)$

Wherein, T _delaythe maximum delay of a cosine definition, v ₀it is the transmission rate of underwater sound signal.