CN103686875A - A method for access control of wireless nanosensor network without conflict and equal transmission rate - Google Patents

Abstract

The invention discloses a conflict-free uniform-sending-speed access control method of a wireless nano sensor network. Access control over an access node is achieved through the low-complexity interactive step of the access node and a relay node and simple table look-up calculation on the relay node. The method comprises the steps that the access node sends an access request control package to inform the fact that new data flow in the relay node needs to be relayed, and the relay node is waited to inform the time point for sending a first bit symbol; once the relay node receives the access request control package, table look-up is conducted, and the time point for sending the first bit signal of the access node is calculated, and a control package is replied to inform the access node. The method that the relay node is used for calculating the time point for sending the first bit symbol of the access node is the core of the conflict-free uniform-sending-speed access control method.

Description

A method for access control of wireless nanosensor network without conflict and equal transmission rate

technical field

The invention relates to an access control method for transmission rates without conflicts in wireless communication, and the method is suitable for wireless nanometer sensor networks.

technical background

With the rapid development of nanotechnology in recent years, it is expected to be able to manufacture sensors with nanoscale size, that is, nanosensors, in the near future. The network formed by interconnecting nanosensors through wireless communication technology is called wireless nanosensor network. This type of network has a very broad application prospect in the fields of environment, medical treatment and industry. Since nanosensor nodes are only about a few hundred nanometers in size and the processing power of their nanoprocessors is extremely limited, designing a communication protocol with extremely low computational complexity is one of the key issues to be studied in wireless nanosensor networks.

For the sub-protocol design of each layer of the wireless nanosensor network communication protocol, including the design of the modulation mode of the physical layer and the design of the multiple access method of the data link layer, etc., the computational complexity needs to be considered. As for the design of the modulation mode of the physical layer, the OOK modulation is one of the more promising modulation methods for wireless nanosensors due to its low complexity. The OOK modulation method is to send a pulse signal to indicate the transmission bit "1", and keep the radio quiet, that is, no voltage signal is sent on the antenna to indicate the transmission bit "0". As for the design of the medium access control method of the data link layer, there have been many literatures and patents so far that have designed multiple access methods suitable for different wireless networks, such as the IEEE 802.11 MAC protocol suitable for wireless local area networks, etc. . However, these methods are all designed for macro nodes with high computing power, and their design does not deliberately pursue low computational complexity. For example, the multiple access method of wireless local area network is based on the complex Channel access mechanism, while the cellular network using CDMA technology realizes multiple access by generating complex mutually orthogonal spread spectrum codes. Therefore, these existing high-complexity multiple access methods are not suitable for nanosensor nodes with extremely limited processing capabilities.

For a wireless nanosensor network using OOK modulation, if each nanosensor node adopts the following sending method: every time a bit symbol is sent out, it is idle for a fixed time interval T before sending the next bit symbol, which can greatly reduce the number of nanonodes. The frequency of collisions between symbol transmissions. Since the time interval T is the same for all sensor nodes, all sensor nodes have the same sending rate. This OOK modulation-based transmission mode in which there is a fixed time interval between the transmission of two bit symbols is called time-domain extended OOK modulation. However, for the existing time-domain extended OOK modulation method, when two adjacent nodes that want to start sending bit information start to send the first bit symbol at the same time, that is, the first bit transmission conflicts, then All their subsequent bit transmissions will collide, resulting in a large number of bit reception errors at the receiving node. Therefore, designing and developing an access control method based on OOK modulation, which has low complexity and can effectively coordinate the transmission time of nanonodes can effectively reduce or even completely eliminate symbol conflicts.

Contents of the invention

In order to overcome the deficiency that continuous symbol collisions may occur in the existing time-domain extended OOK modulation technology, the present invention proposes an access control method for transmission rates such as collision-free wireless nanometer sensor networks. The method effectively coordinates the sending time of the nano-nodes through operations between nodes with lower complexity, thereby avoiding consecutive symbol collisions in the sending of two adjacent nodes and achieving no-sign collisions. Therefore, this technology can be applied to the wireless nanosensor network, and effectively guarantee the reliability of nanosensor bit transmission.

In order to realize above-mentioned technical task, the present invention adopts following technical solution:

1. An access control method for transmission rates such as a wireless nanosensor network without conflicts, characterized in that it consists of two parts: "establishment of a periodic translation scale" and "access control based on a periodic translation scale"; wherein , the "establishment of the periodic translation scale" includes the following specific steps:

Step 1: Set i=1;

Step 2: Add the i-th row in the periodic translation scale, this row contains two cells, the first cell is used to store integer values, and the second cell is used to store decimal values;

其中

参数T_S是物理层发送一个调制符号所消耗的时间，T是根据网络时延等方面的要求而预先设置好的同一个节点上相邻两个比特发送的时间间隔,它是T_S的整数倍的值；Step 3: Set the first cell content of the i-th row of the table to 0, and set the second cell content of the i-th row of the table to

in

The parameter T _S is the time consumed by the physical layer to send a modulation symbol. T is the time interval between two adjacent bits sent on the same node that is preset according to the requirements of network delay and other aspects. It is an integer of T _S times the value;

Step 4: Set i←i+1, if i≤K, skip to step 2, otherwise go to step 4. in,

Step five: end.

Wherein, the "access control based on the periodic translation scale" includes the following specific steps:

Step 1: the access node sends an access request control packet to the relay node to notify the relay node that the access node has a new data flow to be sent to the relay node;

Step 2: the relay node receives the access request control packet sent by the access node;

Step 3: The relay node sets i=1;

Step 4: The relay node reads the value stored in the first cell of the i-th row in the periodic translation scale stored by itself, and records the value as Flag[i]. If Flag[i] is 0, read out the value stored in the second cell of the i-th row, record the value as ΔT _i , and skip to step six; if Flag[i] is 1, go to step five;

Step 5: The relay node sets i←i+1, if i>K, then end the operation and does not reply any control packet to the access node to indicate rejection of its access request; if i≤K, then skip to step 4;

Step 6: The relay node first sets the content of the first cell in the i-th row to 1, then records the time point t ₁ +ΔT _i in the control packet to be replied and sends the control packet to the access node , where ΔT _i is the value read from the second cell in row i of the table in step 4, if the current access node is the first access node, then t ₁ =0, otherwise t ₁ is the first access node The next bit sending time point of the ingress node;

Step 7: The access node receives the reply control packet from the relay node, and then reads out the sending time point t ₁ +ΔT _i specified by the relay node from the packet;

Step 8: The access node sends the first bit at the time point t ₁ +ΔT _i , and sends a bit every time T until all the information bits are sent.

Step 9: The relay node receives the information bits sent by the access node, and after receiving all the information bits of the access node, sets the content of the first cell in the i-th row to 0.

Technical characteristics and effects of the present invention:

1) The present invention has low implementation complexity. Since the periodic translation table to be stored by each relay node is first established in the deployment stage of the wireless nanosensor network, in the access control stage, the access node and the relay node only need to perform simple control packet sending and receiving and processing .

2) The present invention overcomes the shortcoming that continuous symbol collision may occur in OOK modulation of time domain extension, and realizes transmission without symbol collision.

3) Since all sending nodes have the same sending rate, the present invention achieves better node sending fairness.

Description of drawings

Fig. 1 is a schematic diagram of nanosensor data transmission in the present invention.

Fig. 2 is the execution process of the access control method of the present invention.

Fig. 3 is a schematic diagram of a bit symbol sending time of an access node.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

In the fabrication stage of nanosensors or in the deployment stage of the wireless nanosensor network, according to the establishment method of the periodic translation scale of the present invention, the stored periodic translation scale is established and stored in each nanosensor.

In the operation stage of the nanosensor network, when a certain nanosensor node, that is, a relay node, needs to relay multiple data streams, as shown in Figure 1, the relay node is responsible for coordinating the bit symbol transmission time of each access node.

Specifically, when a new data flow passing through the relay node occurs, such as data flow 2 in FIG. 1 , the operations of the access node 2 and the relay node are shown in FIG. 2 . According to the steps described in the access control based on the periodic translation scale of the present invention, the access node 2 first sends an access request control packet to the relay node when the wireless medium is idle, and all bits of the packet are sent out continuously, No time is left idle between bit transmissions. After the relay node receives the access request control packet, it reads line by line from the first row in its own stored periodic translation table, if it is found that the first cell storage values of all K rows of the table are If it is 1, the operation is ended and no control packet is replied to the access node to indicate that its access request is rejected; if the row whose first cell stores a value of 0 is read, the second cell in the row is read grid storage value, with ΔT _i said the value. The relay node sets the content of the first cell of this row to 1 to indicate that the periodic translation of this row has been arranged for a certain access node, and then records the time point t ₁ +ΔT _i in the to-be-reply In the control packet and send the control packet to the access node, if the current access node is the first access node, then t ₁ =0, otherwise t ₁ is the next bit sending time point of the first access node. The access node receives the reply control packet from the relay node, and then reads the sending time point t ₁ +ΔT _i specified by the relay node from the packet, and sends the first bit at the time point t ₁ +ΔT _i , and then send a bit every time T until all information bits are sent. After the relay node has received all the information bits of the access node, the content of the first cell in the i-th row returns to 0 to indicate that the period shift of this row can be arranged for use by a certain access node in the future.

After each new access node starts to transmit according to the time point arranged by the relay node, there is no conflict in the symbol transmission of each access node, as shown in FIG. 3 , the transmission of four access nodes.

Wherein, the "establishment of the periodic translation scale" includes the following specific steps:

Step 1: Set i=1;

Step 2: Add the i-th row in the periodic translation scale, this row contains two cells, the first cell is used to store integer values, and the second cell is used to store decimal values;

其中

参数T_S是物理层发送一个调制符号所消耗的时间，T是根据网络时延等方面的要求而预先设置好的同一个节点上相邻两个比特发送的时间间隔,它是T_S的整数倍的值；Step 3: Set the first cell content of the i-th row of the table to 0, and set the second cell content of the i-th row of the table to

in

The parameter T _S is the time consumed by the physical layer to send a modulation symbol. T is the time interval between two adjacent bits sent on the same node that is preset according to the requirements of network delay and other aspects. It is an integer of T _S times the value;

Step 4: Set i←i+1, if i≤K, skip to step 2, otherwise go to step 4. in,

Step five: end.

Wherein, the "access control based on the periodic translation scale" includes the following specific steps:

Step 1: the access node sends an access request control packet to the relay node to notify the relay node that the access node has a new data flow to be sent to the relay node;

Step 2: the relay node receives the access request control packet sent by the access node;

Step 3: The relay node sets i=1;

Step 4: The relay node reads the value stored in the first cell of the i-th row in the periodic translation scale stored by itself, and records the value as Flag[i]. If Flag[i] is 0, read out the value stored in the second cell of the i-th row, record the value as ΔT _i , and skip to step six; if Flag[i] is 1, go to step five;

Step 5: The relay node sets i←i+1, if i>K, then end the operation and does not reply any control packet to the access node to indicate rejection of its access request; if i≤K, then skip to step 4;

Step 6: The relay node first sets the content of the first cell in the i-th row to 1, then records the time point t ₁ +ΔT _i in the control packet to be replied and sends the control packet to the access node , where ΔT _i is the value read from the second cell in row i of the table in step 4, if the current access node is the first access node, then t ₁ =0, otherwise t ₁ is the first access node The next bit sending time point of the ingress node;

Step 7: The access node receives the reply control packet from the relay node, and then reads out the sending time point t ₁ +ΔT _i specified by the relay node from the packet;

Step 8: The access node sends the first bit at the time point t ₁ +ΔT _i , and sends a bit every time T until all the information bits are sent.

Step 9: The relay node receives the information bits sent by the access node, and after receiving all the information bits of the access node, sets the content of the first cell in the i-th row to 0.

Claims (1)

1. A method for access control of transmission rates such as a wireless nanosensor network without conflicts, characterized in that: it is composed of two parts: "establishment of the periodic translation scale" and "access control based on the periodic translation scale"; wherein , the "establishment of the periodic translation scale" includes the following specific steps: Step 1: Set i=1; Step 2: Add the i-th row in the periodic translation scale, this row contains two cells, the first cell is used to store integer values, and the second cell is used to store decimal values; Step 3: Set the first cell content of the i-th row of the table to 0, and set the second cell content of the i-th row of the table to

in

The parameter T _S is the time consumed by the physical layer to send a modulation symbol. T is the time interval between two adjacent bits sent on the same node that is preset according to the requirements of network delay and other aspects. It is an integer of T _S times the value; Step 4: Set i←i+1, if i≤K, skip to step 2, otherwise go to step 4. in,

Step five: end. Wherein, the "access control based on the periodic translation scale" includes the following specific steps: Step 1: the access node sends an access request control packet to the relay node to notify the relay node that the access node has a new data flow to be sent to the relay node; Step 2: the relay node receives the access request control packet sent by the access node; Step 3: The relay node sets i=1; Step 4: The relay node reads the value stored in the first cell of the i-th row in the periodic translation scale stored by itself, and records the value as Flag[i]. If Flag[i] is 0, read out the value stored in the second cell of the i-th row, record the value as ΔT _i , and skip to step six; if Flag[i] is 1, go to step five; Step 5: The relay node sets i←i+1, if i>K, then end the operation and does not reply any control packet to the access node to indicate rejection of its access request; if i≤K, then skip to step 4; Step 6: The relay node first sets the content of the first cell in the i-th row to 1, then records the time point t ₁ +ΔT _i in the control packet to be replied and sends the control packet to the access node , where ΔT _i is the value read from the second cell in row i of the table in step 4, if the current access node is the first access node, then t ₁ =0, otherwise t ₁ is the first access node The next bit sending time point of the ingress node; Step 7: The access node receives the reply control packet from the relay node, and then reads out the sending time point t ₁ +ΔT _i specified by the relay node from the packet; Step 8: The access node sends the first bit at the time point t ₁ +ΔT _i , and sends a bit every time T until all the information bits are sent. Step 9: The relay node receives the information bits sent by the access node, and after receiving all the information bits of the access node, sets the content of the first cell in the i-th row to 0.

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