CN102098774B - Energy-saving wireless local area network (WLAN) all-channel shielding method - Google Patents

Abstract

The invention relates to an energy-saving wireless local area network (WLAN) all-channel shielding method, and belongs to the technical field of wireless security. The method comprises the following steps of: starting a shielding device to scan channels of the WLAN, and recording the maximum value of a received signal strength indicator (RSSI) on each working channel; calculating the wireless propagation loss (PL) from the shielding device end to the communication equipment end with the maximum RSSI on each channel; determining the minimum transmitting power Yi,j at which the shielding device working on an i channel makes the throughput of a j channel reduced to zero; finding out the maximum value of Yi,j when the shielding device works in different channels and finding out the minimum value Yk, wherein the corresponding channel k is the optimal working channel of the shielding device; and setting the working channel of the shielding device as k, and transmitting a shielding signal at Yk power. By the method, all channels can be interfered at the same time, the channel throughput is reduced at the same time, the problem that an interference signal cannot be transmitted when the original channel throughput is raised and skipped due to channel skip is solved, and interference efficiency is improved.

Description

A kind of energy-conservation WLAN (wireless local area network) all-channel screen method

Technical field

The invention belongs to the security in wireless network field, be specifically related to a kind of WLAN (wireless local area network) data communication shielding mechanism, by detection, the analysis to each channel, launch certain power emission shielded signal, to reduce the channel data throughput, reach shield effectiveness.

Background technology

In Now Domestic, international exchange, WLAN (wireless local area network) becomes the indispensable communications platforms such as government, army, public security, diplomacy and secret scientific research.In important concerning security matters place, the technical security Monitoring and protection that carries out WLAN such as places such as meeting room, research and development chamber, accounting office, planning, commander and monitoring is significant.

11 channels of the WLAN (wireless local area network) proportion 2.412-2.462GHz of IEEE 802.11b, Wireless Telecom Equipment are operated on wherein any one channel.The 5MHz because the centre frequency of per two channels only is separated by causes every adjacent channel to have the band overlapping phenomenon, and this produces data transfer and disturbs, and channel is separated by nearer, disturbs larger.It is generally acknowledged that channel 1,6,11 frequency band are not overlapping, working at these three channels can not produce interference, so utilize these nonoverlapping channels.In fact, 802.11b does not have the bandwidth of each channel of standard, regulation be centre frequency and spectral mask (spectral mask).802.11b the spectral mask requirements of regulation is: at centre frequency ± 11MHz place, the 20dB that decays at least, ± 30MHz place decay 40dB.This shows that centre frequency is that 6 channels of 2.448GHz are within the frequency range scope of 1 channel of 2.423GHz in centre frequency still, the impact between just is less than using other frequency ranges.In fact, work in respectively 1 at wireless device transmitting terminal and receiving terminal, during 6 channel, reach certain numerical value if strengthen the transmitting power of transmitting terminal, receiving terminal just can be received effective energy frequency spectrum.Traditional shielding device adopts channel redirect method mostly: establishing the channel of working in the channel is C ₁, C ₂, C ₃The shielding time of shielding device is respectively T ₁, T ₂, T ₃The shielding device is respectively at T ₁, T ₂, T ₃Time slot jumps to channel C ₁, C ₂, C ₃Carry out co-channel interference, the shielding device can only disturb a channel in a time slot, and when shielding device at channel hopping, there is some milliseconds time can not launch shielded signal, this is so that jamming effectiveness is low, shield with the method, the throughput of channel can only be reduced to 2/3rds original (channel of work is 3).

Summary of the invention

The objective of the invention is to overcome the above-mentioned deficiency of prior art, propose a kind of throughput of all-channel that can guarantee and reduce to zero, and reach energy-efficient all-channel screen method.For this reason, the present invention adopts following technical scheme:

A kind of energy-conservation 802.11b WLAN (wireless local area network) all-channel screen method is characterized in that, comprises following step:

(1) start 11 channels of shielding device scanning 802.11b WLAN (wireless local area network), the received signal strength value RSSI of communication equipment and place channel value in the Sampling network are recorded in the maximum of each working channel received signal strength value RSSI, construction set: X={X ₁X ₂X ₁₁, X _j, j=1,2 ..., 11, the maximum of the upper received signal strength value RSSI of expression channel j;

(2) regional environment that covers according to the 802.11b WLAN (wireless local area network) is selected the radio transmission loss model, calculates the radio transmission loss PL of shielding device end communication equipment end of RSSI maximum to each channel, construction set: PL={PL ₁PL ₂PL ₁₁, PL _j(j=1,2 ..., 11) and represent that shielding device end is to the radio transmission loss value of the communication equipment end of the upper RSSI maximum of channel j;

(3) for every group of i and j, the shielding device of determining to be operated on the i channel makes the throughput of the communication equipment end on the j channel reduce to zero minimum received signal strength value and the difference DELTA RSSI of the communication equipment on the j channel between the minimum received signal strength value of the received signal strength value of the shielding device end on the i channel _{I, j}

(4) for every group of i and j, the shielding device of determining to be operated on the i channel makes the throughput of the communication equipment end on the j channel reduce to zero minimum received signal strength value RSSI _{I, j}=Δ RSSI _{I, j}+ X _j

(5) establish X _{I, j}The shielding device that expression is operated on the i channel makes the throughput of j channel reduce to zero minimum emissive power, calculates Y _{I, j}=RSSI _{I, j}+ PL _j

(6) find out shielding device Y when being operated in different channels _{I, j}Maximum, therefrom find out minimum value Y from these maximums _k, this minimum value is required minimum emissive power, corresponding channel k is the best effort channel of shielding device;

The working channel that (7) will shield device is set as k, with Y _kThe power emission shielded signal;

(8) shielding is thought highly of and is newly begun all-channel scanning, detects the RSSI of each channel, repeats (2)-(7) process.

Wherein, the Δ RSSI in the step (3) _{I, j}Obtain according to following method:

(a) communication equipment wireless signal emission, the shielding device detects the received signal strength value RSSI of communication equipment _jAnd the throughput on the channel j;

(b) shielding device emission shielded signal increases the transmitting power that shields device, until the j channel throughput just reduces to zero;

(c) record the received signal strength value RSSI that shields device at the communication equipment end _i

(d) calculate Δ RSSI _{I, j}=RSSI _i-RSSI _j

The present invention disturbs simultaneously to whole channels, guarantees that channel throughput reduces simultaneously, avoided channel hopping to cause former channel throughput to go up and redirect during can not launch the problem of interference signal, improved jamming effectiveness.The present invention proposes a kind of minimum emissive power (P _Min) algorithm, can reach energy-saving effect.Within effective interference time (T), consumed energy is: W=P _MinT; Traditional shielding algorithm consumed energy is the quantity that W=nPT(n represents working channel), contrast can be found out, tradition screen method consumed energy is more when the channel quantity of working is more, and average throughput descends lower, only be original n/one, interference effect is not obvious when channel is busy with one's work.

Description of drawings

Fig. 1 is the flow chart of screen method of the present invention.

Concrete execution mode

The present invention proposes a kind of all-channel screen method of energy-conservation 802.11b WLAN (wireless local area network), the shielding device that adopts can be the equipment such as embedded board, Portable notebook, is furnished with the adjustable wireless network card of power, signal detection system.Wireless network card is set makes it continue uninterruptedly to transmit.Referring to Fig. 1, it below is detailed execution mode of the present invention.

(1) start 11 channels of shielding device Wlan scanning, the RSSI(received signal strength value of communication equipment in the Sampling network) and place channel value, be recorded in the maximum of each working channel RSSI, construction set: X={X ₁X ₂X ₁₁, X _j(j=1,2 ..., 11) and represent that channel j goes up the maximum of RSSI;

(2) regional environment that covers according to WLAN (wireless local area network) is selected the radio transmission loss model, calculates the radio transmission loss PL of shielding device end RSSI maximum communication equipment end to each channel, construction set: PL={PL ₁PL ₂PL ₁₁, PL _j(j=1,2 ..., 11) and represent that shielding device end is to the radio transmission loss value of the communication equipment end of the upper RSSI maximum of channel j;

(3) determine minimum △ RSSI: Δ RSSI _{I, j}, i represents to shield the working channel of device, and j represents the working channel of communication equipment, Δ RSSI _{I, j}Assay method be following a few step:

The working channel that (a) will shield device and communication equipment is set as respectively i, j;

(b) communication equipment wireless signal emission, the shielding device detects the received signal strength value RSSI of communication equipment _jAnd the throughput on the channel j;

(c) shielding device emission shielded signal increases the transmitting power that shields device, until the j channel throughput just reduces to zero;

(d) record the received signal strength value RSSI that shields device at the communication equipment end _i

(e) calculate minimum received signal strength difference: Δ RSSI _{I, j}=RSSI _i-RSSI _j

(4) determine that the shielding device is at the minimum RSSI:RSSI of communication equipment end _{I, j}=Δ RSSI _{I, j}+ X _j(RSSI _{I, j}Expression shielding device (i channel) makes the throughput of j channel reduce to zero minimum RSSI);

(5) calculate transmitting power: Y _{I, j}=RSSI _{I, j}+ PL _j(Y _{I, j}Expression shielding device (i channel) makes the throughput of j channel reduce to zero minimum emissive power), Y when finding out the shielding device and being operated in different channels _{I, j}Maximum, relatively these maximums are therefrom found out minimum value Y _k, this minimum value is required minimum emissive power, corresponding channel k is the best effort channel of shielding device;

The working channel that (6) will shield device is set as k, with Y _kThe power emission shielded signal;

(7) shielding is thought highly of and is newly begun all-channel scanning, detects the RSSI of each channel, repeats (2)-(6) process.

Claims (2)

1. an energy-conservation WLAN (wireless local area network) all-channel screen method is characterized in that, comprises following step:

(1) start 11 channels of shielding device scanning 802.11b WLAN (wireless local area network), the received signal strength value RSSI of communication equipment and place channel value in the Sampling network are recorded in the maximum of each working channel received signal strength value RSSI, construction set: X={X ₁X ₂X ₁₁, X _jThe maximum of the upper received signal strength value RSSI of expression channel j, wherein, j=1,2 ..., 11;

(2) regional environment that covers according to the 802.11b WLAN (wireless local area network) is selected the radio transmission loss model, calculates the radio transmission loss PL of shielding device end communication equipment end of RSSI maximum to each channel, construction set:

PL={PL ₁PL ₂PL ₁₁, PL _jExpression shields the device end to the radio transmission loss value of the communication equipment end of the upper RSSI maximum of channel j, wherein, j=1,2 ..., 11;

(3) for every group of i and j, the shielding device of determining to be operated on the i channel makes the throughput of the communication equipment end on the j channel reduce to zero minimum received signal strength value and the difference DELTA RSSI of the communication equipment on the j channel between the minimum received signal strength value of the received signal strength value of the shielding device end on the i channel _{I, j}

(4) for every group of i and j, the shielding device of determining to be operated on the i channel makes the throughput of the communication equipment end on the j channel reduce to zero minimum received signal strength value RSSI _{I, j}=Δ RSSI _{I, j}+ X _j

(5) establish Y _{I, j}The shielding device that expression is operated on the i channel makes the throughput of j channel reduce to zero minimum emissive power, calculates Y _{I, j}=RSSI _{I, j}+ PL _j

(6) find out shielding device Y when being operated in different channels _{I, j}Maximum, therefrom find out minimum value Y from these maximums _k, this minimum value is required minimum emissive power, corresponding channel k is the best effort channel of shielding device;

The working channel that (7) will shield device is set as k, with Y _kThe power emission shielded signal;

(8) shielding is thought highly of and is newly begun all-channel scanning, detects the RSSI of each channel, repeats (2)-(7) process.

2. energy-conservation WLAN (wireless local area network) all-channel screen method according to claim 1 is characterized in that the Δ RSSI in the step (3) _{I, j}Obtain according to following method:

(a) communication equipment wireless signal emission, the shielding device detects the received signal strength value RSSI of communication equipment _jAnd the throughput on the channel j;

(b) shielding device emission shielded signal increases the transmitting power that shields device, until the j channel throughput just reduces to zero;

(c) record the received signal strength value RSSI that shields device at the communication equipment end _i

(d) calculate Δ RSSI _{I, j}=RSSI _i-RSSI _j

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