Data transmission method for wireless network
First Claim
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1. A data transmission method for a wireless network that includes at least one transmitter and one receiver, comprising the steps of:
- by the receiver, periodically estimating a signal-to-noise ratio in a signal of the transmitter and the estimate is transmitting the estimate from the receiver to the transmitter;
by the transmitter, periodically estimating an average number of idle slots between two successive transmissions in the network;
estimating a number of active stations, consisting of transmitters and receivers, in the network using the estimate of the average number of idle slots between two successive transmissions in the network;
estimating station collision probability and an average number of stations in collision using the estimate of number of active stations in the network, before data unit transmission;
extrapolating the obtained estimates of the signal-to-noise ratio, thus obtaining the extrapolated estimate of the signal-to-noise ratio;
determining the optimal fragment size, optimal transmission rate and the respective value of network throughput for the basic data transmission mechanism using the extrapolated signal-to-noise ratio estimate and estimates of station collision probability and the average number of stations in collision;
determining the optimal fragment size, optimal transmission rate and their respective value of network throughput for the request-to-send/clear-to-send data transmission mechanism using the extrapolated signal-to-noise ratio estimate and estimates of station collision probability and the average number of stations in collision;
selecting the basic data transmission mechanism with the respective optimal fragment size and optimal transmission rate for data unit transmission, if the value of the network throughput for the basic data transmission mechanism is greater than the value of the network throughput for the request-to-send/clear-to-send data transmission mechanism;
selecting the request-to-send/clear-to-send data transmission mechanism with the respective optimal fragment size and optimal transmission rate for the data unit transmission, if the value of the network throughput for the request-to-send/clear-to-send data transmission mechanism is greater than the value of the network throughput for the basic data transmission mechanism, the selected data transmission mechanism and its respective optimal fragment size are used for transmission of all fragments of a data unit, the selected optimal transmission rate is used at the first transmission of the first fragment of the data unit, before the next transmission of a fragment of the data unit;
extrapolating the estimates of the signal-to-noise ratio obtained up to the moment of the beginning of the next transmission of a fragment of the data unit, thus obtaining a new extrapolated estimate of the signal-to-noise ratio, for the next transmission of a fragment of the data unit; and
selecting a new optimal transmission rate using the current estimates of average number of idle slots between two successive transmissions in the network, station collision probability and the average number of stations in collision, and the new extrapolated estimate of the signal-to-noise ratio.
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Abstract
Disclosed is a device and method that relates to radio engineering and especially to data transmission in a wireless local area network. The method improves the throughput of the wireless local area network, by selecting a transmission rate, data transmission mechanism and a fragment size which maximize the network throughput considering the receiving conditions on the receiver (bit error rate in the transmitted data units of the transmitter ) and taking into account the current network loading are selected for transmission of data units.
14 Citations
33 Claims
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1. A data transmission method for a wireless network that includes at least one transmitter and one receiver, comprising the steps of:
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by the receiver, periodically estimating a signal-to-noise ratio in a signal of the transmitter and the estimate is transmitting the estimate from the receiver to the transmitter; by the transmitter, periodically estimating an average number of idle slots between two successive transmissions in the network; estimating a number of active stations, consisting of transmitters and receivers, in the network using the estimate of the average number of idle slots between two successive transmissions in the network; estimating station collision probability and an average number of stations in collision using the estimate of number of active stations in the network, before data unit transmission; extrapolating the obtained estimates of the signal-to-noise ratio, thus obtaining the extrapolated estimate of the signal-to-noise ratio; determining the optimal fragment size, optimal transmission rate and the respective value of network throughput for the basic data transmission mechanism using the extrapolated signal-to-noise ratio estimate and estimates of station collision probability and the average number of stations in collision; determining the optimal fragment size, optimal transmission rate and their respective value of network throughput for the request-to-send/clear-to-send data transmission mechanism using the extrapolated signal-to-noise ratio estimate and estimates of station collision probability and the average number of stations in collision; selecting the basic data transmission mechanism with the respective optimal fragment size and optimal transmission rate for data unit transmission, if the value of the network throughput for the basic data transmission mechanism is greater than the value of the network throughput for the request-to-send/clear-to-send data transmission mechanism; selecting the request-to-send/clear-to-send data transmission mechanism with the respective optimal fragment size and optimal transmission rate for the data unit transmission, if the value of the network throughput for the request-to-send/clear-to-send data transmission mechanism is greater than the value of the network throughput for the basic data transmission mechanism, the selected data transmission mechanism and its respective optimal fragment size are used for transmission of all fragments of a data unit, the selected optimal transmission rate is used at the first transmission of the first fragment of the data unit, before the next transmission of a fragment of the data unit; extrapolating the estimates of the signal-to-noise ratio obtained up to the moment of the beginning of the next transmission of a fragment of the data unit, thus obtaining a new extrapolated estimate of the signal-to-noise ratio, for the next transmission of a fragment of the data unit; and selecting a new optimal transmission rate using the current estimates of average number of idle slots between two successive transmissions in the network, station collision probability and the average number of stations in collision, and the new extrapolated estimate of the signal-to-noise ratio. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A data transmission method for a wireless network that includes at least one transmitter and one receiver, comprising the steps of:
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estimating an average number of idle slots between two successive transmissions in a network by a transmitter; estimating a number of active stations, consisting of transmitters and receivers, in a network using the estimate of average number of idle slots between two successive transmissions in a network; estimating station collision probability and an average number of stations in a collision using the estimate of number of active stations in a network; transmitting L1, L2, L3, L4 data units, where L1, L2, L3, L4 are greater than or equal to 1, from the transmitter to a receiver using a basic data transmission mechanism, first, second, third and fourth transmission rates V1, V2, V3, V4 and such a fragment size; receiving by the transmitter the same for all L1, L2, L3, L4 data units so that one data unit contain two or more fragments and first two fragments of each data unit have the same size, acknowledgements for those fragments of L1, L2, L3, L4 data units received without errors at the receiver; estimating bit error rate α
z,V1, α
z,V2, α
z,V3, α
z,V4 for the first, second, third and fourth transmission rate in the transmitted data units of the transmitter using information about a number of acknowledgements received after transmission of L1, L2, L3, L4 data units;determining a fragment size {tilde over (x)}1(Basic), {tilde over (x)}2(Basic), {tilde over (x)}3(Basic), {tilde over (x)}4(Basic) for the first, second, third and fourth transmission rate V1, V2, V3, V4 and the basic data transmission mechanism using an estimate of the bit error rate α
z,V1 α
z,V1, α
z,V2, α
z,V3, α
z,V4 for the first, second, third and fourth transmission rate V1, V2, V3, V4 and the estimate of average number of idle slots between two successive transmissions in a network;determining a value of the network throughput W1(Basic), W2(Basic), W3(Basic), W4(Basic) for the first, second, third and fourth transmission rate V1, V2, V3, V4 and basic data transmission mechanism by means of the estimate of bit error rate α
z,V1 α
z,V1, α
z,V2, α
z,V3, α
z,V4 for the first, second, third and fourth transmission rate V1, V2, V3, V4, fragment size {tilde over (x)}1(Basic), {tilde over (x)}2(Basic), {tilde over (x)}3(Basic), {tilde over (x)}4(Basic) for the first, second, third and fourth transmission rate V1, V2, V3, V4 and the basic data transmission mechanism, estimates of the average number of idle slots between two successive transmissions in the network, station collision probability and the average number of stations in a collision;determining a fragment size {tilde over (x)}1(RTS-CTS), {tilde over (x)}2(RTS-CTS), {tilde over (x)}3(RTS-CTS), {tilde over (x)}4(RTS-CTS) for the first, second, third and fourth transmission rate V1, V2, V3, V4 and request-to-send/clear-to-send data transmission mechanism by means of the estimate of the bit error rate α
z,V1, α
z,V2, α
z,V3, α
z,V4 for the first, second, third and fourth transmission rate V1, V2, V3, V4, estimates of average number of idle slots between two successive transmissions in the network, station collision probability and the average number of stations in a collision, a value of the network throughput W1(RTS-CTS), W2(RTS-CTS), W3(RTS-CTS), W4(RTS-CTS) for the first, second, third and fourth transmission rate V1, V2, V3, V4 and request-to-send/clear-to-send data transmission mechanism is determined by means of the estimate of the bit error rate α
z,V1, α
z,V2, α
z,V3, α
z,V4 for the first, second, third and fourth transmission rate V1, V2, V3, V4, fragment size {tilde over (x)}1(RTS-CTS), {tilde over (x)}2(RTS-CTS), {tilde over (x)}3(RTS-CTS), {tilde over (x)}4(RTS-CTS) for the first, second, third and fourth transmission rate V1, V2, V3, V4 and the request-to-send/clear-to-send data transmission mechanism, estimates of the average number of idle slots between two successive transmissions in the network, station collision probability and the average number of stations in a collision;determining a value of the network throughput W1(max), W2(max), W3(max), W4(max) for the first, second, third and fourth transmission rate V1, V2, V3, V4 as a maximal value from the value of the network throughput W1(Basic), W2(Basic), W3(Basic), W4(Basic) for the first second, third and fourth transmission rate V1, V2, V3, V4 and the basic data transmission mechanism and the value of the network throughput W1(RTS-CTS), W2(RTS-CTS), W3(RTS-CTS), W4(RTS-CTS) for the first, second, third and fourth transmission rate V1, V2, V3, V4 and the request-to-send/clear-to-send data transmission mechanism; comparing the value of the network throughput W1(max) for the first transmission rate V1 and the value of the network throughput W2(max) for the second transmission rate V2; if the value of the network throughput W1(max) for the first transmission rate V1 is greater than the value of the network throughput W2(max) for the second transmission rate V2, selecting the first transmission rate V1 for data transmission; comparing the value of the network throughput W1(Basic) for the first transmission rate V1 and the basic transmission mechanism and the value of the network throughput W1(RTS-CTS) for the first transmission rate V1 and the request-to-send/clear-to-send data transmission mechanism; if the value of the network throughput W1(Basic) for the first transmission rate V1 and the basic transmission mechanism is greater than or equal to the value of the network throughput W1(RTS-CTS) for the first transmission rate V1 and the request-to-send/clear-to-send data transmission mechanism, selecting the basic transmission mechanism and fragment size {tilde over (x)}1(Basic) for the first transmission rate V1 and basic transmission mechanism for data transmission, otherwise, selecting the request-to-send/clear-to-send data transmission mechanism and fragment size {tilde over (x)}1(RTS-CTS) for the first transmission rate V1 and request-to-send/clear-to-send data transmission mechanism for data transmission, if the value of the network throughput W1(max) for the first transmission rate V1 is less than the value of the network throughput W2(max) for the second transmission rate V2; comparing the value of the network throughput W2(max) for the second transmission rate V2 and the value of the network throughput W3(max) for the third transmission rate V3; if the value of the network throughput W2(max) for the second transmission rate V2 is more than the value of the network throughput W3(max) for the third transmission rate V3, selecting the second transmission rate V2 for data transmission; comparing the value of the network throughput W2(Basic) for the second transmission rate V2 and the basic transmission mechanism and the value of the network throughput W2(RTS-CTS) for the second transmission rate V2 and the request-to-send/clear-to-send data transmission mechanism; if the value of the network throughput W2(Basic) for the second transmission rate V2 and the basic transmission mechanism is greater than or equal to the value of the network throughput W2(RTS-CTS) for the second transmission rate V2 and the request-to-send/clear-to-send data transmission mechanism, selecting the basic transmission mechanism and fragment size {tilde over (x)}2(Basic) for the second transmission rate V2 and basic transmission mechanism for data transmission, otherwise, selecting the request-to-send/clear-to-send data transmission mechanism and fragment size {tilde over (x)}2(RTS-CTS) for the second transmission rate V2 and request-to-send/clear-to-send data transmission mechanism for data transmission, if the value of the network throughput W2(max) for the second transmission rate V2 is less than the value of the network throughput W3(max) for the third transmission rate V3; comparing the value of the network throughput W3(max) for the third transmission rate V3 and the value of the network throughput W4(max) for the fourth transmission rate V4; if the value of the network throughput W3(max) for the third transmission rate V3 is more than the value of the network throughput W4(max) for the fourth transmission rate V4, selecting the third transmission rate V3 for data transmission; comparing the value of the network throughput W3(Basic) for the third transmission rate V3 and the basic transmission mechanism and the value of the network throughput W3(RTS-CTS) for the third transmission rate V3 and the request-to-send/clear-to-send data transmission mechanism; if the value of the network throughput W3(Basic) for the third transmission rate V3 and the basic transmission mechanism is greater than or equal to the value of the network throughput W3(RTS-CTS) for the third transmission rate V3 and the request-to-send/clear-to-send data transmission mechanism, selecting the basic transmission mechanism and fragment size {tilde over (x)}3(Basic) for the third transmission rate V3 and basic transmission mechanism for data transmission, otherwise, selecting the request-to-send/clear-to-send data transmission mechanism and fragment size {tilde over (x)}3(RTS-CTS) for the third transmission rate V3 and request-to-send/clear-to-send data transmission mechanism for data transmission; if the value of the network throughput W3(max) for the third transmission rate V3 is less than the value of the network throughput W4(max) for the fourth transmission rate V4, selecting the fourth transmission rate V4 for data transmission; comparing the value of the network throughput W4(Basic) for the fourth transmission rate V4 and the basic transmission mechanism and the value of the network throughput W4(RTS-CTS) for the fourth transmission rate V4 and the request-to-send/clear-to-send data transmission mechanism; if the value of the network throughput W4(Basic) for the fourth transmission rate V4 and the basic transmission mechanism is greater than or equal to the value of the network throughput W4(RTS-CTS) for the fourth transmission rate V4 and the request-to-send/clear-to-send data transmission mechanism, selecting the basic transmission mechanism and fragment size {tilde over (x)}4(Basic) for the fourth transmission rate V4 and basic transmission mechanism for data transmission, otherwise, selecting the request-to-send/clear-to-send data transmission mechanism and fragment size {tilde over (x)}4(RTS-CTS) for the fourth transmission rate V4 and request-to-send/clear-to-send data transmission mechanism for data transmission; and transmitting data units from the transmitter to the receiver using the selected transmission rate, data transmission mechanism and fragment size selected for this transmission rate. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33)
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Specification