CN103533622A - Channel sharing method based on power control in underwater sensor network - Google Patents

Abstract

The invention belongs to the field of underwater sensor network communication technologies, and relates to a channel sharing method based on the power control in an underwater sensor network. The channel sharing method comprises the following steps: an RTS (Request To Send) group, a CIS (Channel Information State) group, a DATA group and an ACK (Acknowledgement) group between a sender and a receiver are defined; a channel gain matrix between the other neighbor node and a source node A is defined; when a channel is idle, the source node is capable of transmitting the RTS group with the maximum power, and searching the CIS group of the neighbor node of the channel, and a target node B returns the CIS group containing the channel gain between the nodes at the maximum power; the power of the data is computed, distributed and transmitted by the sending source node A through utilizing a power control algorithm, if the channel is idle, the data group is transmitted by the source node A. According to the channel sharing method, the power consumption and the long-distance transmission are effectively balanced, so that the efficiency of spatial multiplexing is enhanced.

Description

The shared channel method of controlling based on power in underwater sensor network

Technical field

The present invention relates to underwater sensor network communication technical field, is a kind of high spatial reusability, high concurrency and low collision probability based on power, control shared channel method.

Background technology

Underwater sensor network has the feature of propagation loss, noise, multipath effect, Doppler's diffusion and hypermutation propagation delay time, therefore, its environment and feature have determined that transmission medium matter is not radio magnetic wave, but sonar transmission, its transmission rate is under water 1500m/s, is radio magnetic wave 2 * 10 ^-5doubly, these factors all have a strong impact on the throughput of network.

In order to improve the throughput of network, in underwater sensor network, adopt the method for multiple channel access.It is mainly the channel access method adopting based on reservation.For example, having a kind of is the shared channel method proposing in order to solve the problem of concealed terminal, and also having a kind of is the shared channel method proposing in order to solve the problem of long Distance Transmission time delay.Yet network capacity depends on desirable channel capacity, link capacity and spatial reuse situation.When a large amount of node concurrent data, above-mentioned shared channel method efficiency on spatial reuse can not get embodying well.If communication distance surpasses maximum transmission range 22%, RTS/CTS shakes hands and will become invalid.Only have when transmission range approaches maximum transmission distance 56%, RTS/CTS shakes hands just effective.

Summary of the invention

The object of the invention is to overcome the above-mentioned deficiency of prior art, provide a kind of be applicable to underwater sensor network a kind of to control shared channel method based on power, in order to energy efficient preferably with improve spatial multiplex ratio.Technical scheme of the present invention is as follows:

A shared channel method of controlling based on power, is characterized in that, comprises following step:

(1) RTS (sending request grouping), the CIS(channel information state between definition transmit leg and recipient), DATA(packet) and ACK(confirm to divide into groups) 4 kinds of groupings;

(2) define the channel gain matrix between other neighbor node and source node A:

In the situation that not considering background noise, set up the signal interference ratio SIR(signal to interference ratio of underwater sensor network) model:

$\mathrm{SIR}=\frac{R_i\·H_i}{{\mathrm{\Σ}}_{j=1}^{N-1}{P}_j\·H_j}$

Wherein, P _ithe transmitted power that represents channel i, H _irepresent channel i gain, other channel gain is H _j, the transmitted power of other channel is P _j;

Suppose that source node A sends data to destination B node, channel gain is between the two:: H _aB=P _b-P _a, other

Neighbor node with the form that channel gain between source node A is listed as into matrix is:

$H=\left[\begin{array}{ccccc}{H}_{\mathrm{AA}}& H_{\mathrm{AB}}& h_{\mathrm{AC}}& H_{\mathrm{AD}}& ...\\ H_{\mathrm{BA}}& H_{\mathrm{BB}}& H_{\mathrm{BC}}& H_{\mathrm{BD}}& ...\\ H_{\mathrm{CA}}& H_{\mathrm{CB}}& H_{\mathrm{CC}}& H_{\mathrm{CD}}& ...\\ H_{\mathrm{DA}}& H_{\mathrm{DB}}& H_{\mathrm{DC}}& H_{\mathrm{DD}}& ...\\ .& .& .& .& .\\ .& .& .& .& .\\ .& .& .& .& .\end{array}\right];$

(3) when channel idle, source node A sends the RTS grouping of a maximum power, and collects the CIS grouping of channel neighbor node, if B is destination node, B returns to CIS grouping with maximum power, in CIS grouping, has comprised internodal channel gain; Transmission source node A lists channel gain matrix between node by the CIS grouping of collecting, utilize power control algorithm, calculate and distribute and send data power, if channel idle, source node A sends packet, otherwise, channel busy, source node A waits for that next time slot sends packet again after keeping out of the way; After packet sends successfully, return to an ACK(and confirm grouping).

As preferred implementation, a kind of of described underwater sensor network controls shared channel method based on power, and power control algorithm is wherein as follows:

Suppose that A sends data to B, the utility function of optimal throughput is:

$u_{\mathrm{AB}}(P_{\mathrm{AB}},P_{-\mathrm{AB}})=\log (1+\frac{P_{\mathrm{AB}}\·H_{\mathrm{AB}}}{{\mathrm{\Σ}}_{j=1}^{N-1}{H}_j\·P_j})-\mathrm{\Θ}\·P_{\mathrm{AB}}$

Wherein, P _aBrepresent that A is to the transmitted power of B, P _-ABexpression is except giving B transmitted power, and the power between other neighbor node, H _-ABexpression except B, the channel gain between A node and neighbor node, Θ is to be default adjustment factor;

To the differentiate of utility function secondary, if the value of second derivative is less than 0, judge that channel exists Nash Equilibrium point;

To a differentiate of utility function, make it equal 0, obtain Nash Equilibrium point P and distribute power;

Transmission source node A distributes power according to the Nash Equilibrium point P obtaining, and distributes and sends data power.

The present invention proposes the shared channel method of controlling based on power, it defines respectively RTS (Request to send), CIS(Channel Information State), DATA and 4 kinds of groupings of Acknowledgement (ACK), by periodically collecting CIS, divide into groups, calculate and distribute data transmitted power, active balance power consumption and long Distance Transmission, thereby solved when great deal of nodes sends data simultaneously, the problem that data collision collision probability is high, has strengthened the efficiency of spatial reuse.

Embodiment

The present invention adopts a kind of shared channel method of controlling based on power.The method defines respectively RTS (Request to send), CIS(Channel Information State), DATA and 4 kinds of groupings of Acknowledgement (ACK).When channel idle, node A sends RTS grouping with maximum power, and collects the CIS grouping of neighbor node.If B is destination node, B returns to CIS grouping with maximum power.At sending node A end, according to the CIS grouping of collecting, list gain matrix, then utilize power control algorithm, calculate and distribute transmission data power.Channel idle, node A sends packet.Otherwise, channel busy, node A waits for that next time slot sends packet again after keeping out of the way.After packet sends successfully, return to an ACK and confirm grouping.The concrete step of the present invention is as follows:

Step 1: node A, C send RTS grouping jointly with maximum power, and the CIS grouping of periodically collecting neighbor node.B, as the destination of A node, sends CIS grouping with maximum power, and in like manner, D, as the destination of C node, sends CIS with maximum power and divides into groups to C.Then, transmitting terminal A, C, according to the CIS grouping of collecting, set up information gain matrix, utilize power control algorithm, distribute power, complete the transmission of data.

Step 2: the signal interference ratio model of underwater sensor network is:

$\mathrm{SIR}=\frac{P_i\·H_i}{{\mathrm{\Σ}}_{j=1}^{N-1}{P}_j\·H_j+{\mathrm{\θ}}^2}$

Wherein, P _ifor the transmitted power of user i, H _irepresent the gain of user i busy channel, other channel gain is H _j, other user's transmitted power is P _j, θ ²it is background noise.In the situation that not considering background noise, the signal interference ratio of underwater sensor network is:

$\mathrm{SIR}=\frac{R_i\·H_i}{{\mathrm{\Σ}}_{j=1}^{N-1}{P}_j\·H_j}$

Suppose that source node A sends data to destination node B, channel gain is between the two:

H _AB＝P _B-P _A

Other neighbor node with the form that channel gain between source node A is listed as into matrix is:

$H=\left[\begin{array}{ccccc}{H}_{\mathrm{AA}}& H_{\mathrm{AB}}& h_{\mathrm{AC}}& H_{\mathrm{AD}}& ...\\ H_{\mathrm{BA}}& H_{\mathrm{BB}}& H_{\mathrm{BC}}& H_{\mathrm{BD}}& ...\\ H_{\mathrm{CA}}& H_{\mathrm{CB}}& H_{\mathrm{CC}}& H_{\mathrm{CD}}& ...\\ H_{\mathrm{DA}}& H_{\mathrm{DB}}& H_{\mathrm{DC}}& H_{\mathrm{DD}}& ...\\ .& .& .& .& .\\ .& .& .& .& .\\ .& .& .& .& .\end{array}\right];$

I node after shared channel gain matrix, according to non-cooperative game Nash Equilibrium, solves the utility function that obtains optimal throughput between each node of grasp:

u _i(P _i,P _-i,)＝log(1+SINR _i)-Θ·Pi

Suppose that A sends data to B, utility function is:

$u_{\mathrm{AB}}(P_{\mathrm{AB}},P_{-\mathrm{AB}})=\log (1+\frac{P_{\mathrm{AB}}\·H_{\mathrm{AB}}}{{\mathrm{\Σ}}_{j=1}^{N-1}{H}_j\·P_j})-\mathrm{\Θ}\·P_{\mathrm{AB}}$

P _aBrepresent that A is to the transmitted power of B, P _-ABexpression is except giving B transmitted power, and the power between other neighbor node, H _aBrepresent the channel gain between A and B, H _-ABrepresent the channel gain between A and neighbor node, with represent-AB of j, Θ means adjustment factor below, and adjusting utility function is maximum.

First, utility function is carried out to secondary differentiate, obtains:

$\frac{{{\∂u}^2}_{\mathrm{AB}}(P_{\mathrm{AB}},P_{-\mathrm{AB}})}{{\∂}^2{P}_{\mathrm{AB}},}=-\frac{{H^2}_{\mathrm{AB}}}{{(H_{\mathrm{AB}}\·P_{\mathrm{AB}}+{\mathrm{\Σ}}_{j=1}^{N-1}{H}_j\·P_j+{\mathrm{\Θ}}^2)}^2}$

value be less than 0, illustrate that channel exists Nash Equilibrium point.Therefore, Solving Nash Equilibrium point is a process that solves optimum allocation power.

To a differentiate of utility function, make it equal 0, obtain:

$\frac{{\∂u}_{\mathrm{AB}}(P_{\mathrm{AB}},P_{-\mathrm{AB}})}{{\∂P}_{\mathrm{AB}},}=-\frac{H_{\mathrm{AB}}}{(H_{\mathrm{AB}}\·P_{\mathrm{AB}}+{\mathrm{\Σ}}_{j=1}^{N-1}{H}_j\·P_j+{\mathrm{\Θ}}^2)}-\mathrm{\Θ}=0$

$P_{\mathrm{AB}}=\frac{1}{\mathrm{\Θ}}-\frac{{\mathrm{\Σ}}_{j=1}^{N-1}{P}_j\·H_j+{\mathrm{\Θ}}^2}{H_{\mathrm{AB}}}$

Both sides are with being multiplied by H _aB, after transposition, obtain following expression:

$P_{\mathrm{AB}}{H}_{\mathrm{AB}}+{\mathrm{\Σ}}_{j=1}^{N-1}{P}_j\·H_j=\frac{H_{\mathrm{AB}}}{\mathrm{\Θ}}-{\mathrm{\Θ}}^2$

Above formula is expressed as by the form of matrix:

P·H ^*=G ^*

H ^*for channel gain matrix transposition, P is Nash Equilibrium power matrix, and G is one dimension matrix.Sending node A distributes power by the Nash Equilibrium point according to obtaining, thereby the collision of effectively having avoided data to send obtains maximum throughput.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, all any modifications of doing within the spirit and principles in the present invention, be equal to and replace and improvement etc., within all should being included in protection scope of the present invention.

Claims (2)

1. a shared channel method of controlling based on power in underwater sensor network, is characterized in that, comprises following step:

(1) RTS (sending request grouping), the CIS(channel information state between definition transmit leg and recipient), DATA(packet) and ACK(confirm to divide into groups) 4 kinds of groupings;

(2) define the channel gain matrix between other neighbor node and source node A:

In the situation that not considering background noise, set up the signal interference ratio SIR(signal to interference ratio of underwater sensor network) model:

Wherein, P _ithe transmitted power that represents channel i, H _irepresent channel i gain, other channel gain is H _j, the transmitted power of other channel is P _j;

Suppose that source node A sends data to destination B node, channel gain is between the two:: H _aB=P _b-P _a, other neighbor node with the form that channel gain between source node A is listed as into matrix is:

(3) when channel idle, source node A sends the RTS grouping of a maximum power, and collects the CIS grouping of channel neighbor node, if B is destination node, B returns to CIS grouping with maximum power, in CIS grouping, has comprised internodal channel gain; Transmission source node A lists channel gain matrix between node by the CIS grouping of collecting, utilize power control algorithm, calculate and distribute and send data power, if channel idle, source node A sends packet, otherwise, channel busy, source node A waits for that next time slot sends packet again after keeping out of the way; After packet sends successfully, return to an ACK(and confirm grouping).

2. shared channel method according to claim 1, power control algorithm is wherein as follows:

Suppose that A sends data to B, the utility function of optimal throughput is:

Wherein, P _aBrepresent that A is to the transmitted power of B, P _-ABexpression is except giving B transmitted power, and the power between other neighbor node, H _-ABexpression except B, the channel gain between A node and neighbor node, Θ is to be default adjustment factor;

To the differentiate of utility function secondary, if the value of second derivative is less than 0, judge that channel exists Nash Equilibrium point;

To a differentiate of utility function, make it equal 0, obtain Nash Equilibrium point P and distribute power;

Transmission source node A distributes power according to the Nash Equilibrium point P obtaining, and distributes and sends data power.