US 6,615,382 B1 · Method for controlling errors in link layer in wideband wireless communication and computer readable media therefor

Abstract

A method for controlling errors in a wireless link layer using a simultaneous multiple copy scheme and an adaptive forward error correction (FEC) scheme in a wideband wireless communication is provided. The method for controlling errors in a link layer in wideband wireless communication using an automatic repeat request (ARQ) scheme, in which a wideband wireless channel is used for communication between a first node and a second node, includes the steps of (a) estimating the error ratio of a forward (a direction in which a cell is transmitted from the first node to the second node) channel using the state of a backward (a direction in which a cell is transmitted from the second node to the first node) channel, and transmitting a cell, in which a forward error correction (FEC) code having an encoding ratio that varies depending on the estimated error ratio is included in a protocol data unit (PDU) of a wireless link layer, through the forward channel and (b) re-transmitting the copy of a cell transmitted in the step (a), when feedback information that indicates that an error exists in the cell transmitted in the step (a) is received through the backward channel. It is possible to reduce the number of times of re-transmission by improving the probability of correcting forward errors using more error controlling bits as the state of the channel is worse and to minimize the waste of resources using less error controlling bits as the state of the channel is better, to thus obtain the optimal performance and guarantee the minimum delay time.

Claims37

Dependent claims

A method for controlling errors in a link layer in wideband wireless communication using an automatic repeat request (ARQ) scheme, in which a wideband wireless channel is used for communication between a first node and a second node, comprising the steps of:

(a) estimating the error ratio of a forward (a direction in which a cell is transmitted from the first node to the second node) channel using the state of a backward (a direction in which a cell is transmitted from the second node to the first node) channel, and transmitting a cell, in which a forward error correction (FEC) code having an encoding ratio that varies depending on the estimated error ratio is included in a protocol data unit (PDU) of a wireless link layer, through the forward channel;
and
(b) re-transmitting a plurality of copies of a cell transmitted in the step (a), when feedback information that indicates that an error exists in the cell transmitted in the step (a) is received through the backward channel.

A method for controlling errors in a link layer in wideband wireless communication using an ARQ scheme, in which a wideband wireless channel is used for communication between a first node and a second node, comprising the steps of:

(a) estimating the error ratio of a forward (a direction in which a cell is transmitted from the first node to the second node) channel through the state of a backward (a direction in which a cell is transmitted from the second node to the first node) channel;
(b) determining a ratio in which the PDU of an upper layer is converged to the PDU of a wireless link layer on the basis of the error ratio of the forward channel estimated in the step (a);
(c) transmitting the cell of the PDU of the wireless link layer formed according to the convergence ratio determined in the step (b) through the forward channel;
and
(d) re-transmitting a plurality of copies of the cell transmitted in the step (c) when feedback information which indicates that an error exists in the cell transmitted in the step (c) is received through the backward channel.

2 more elements

(a) estimating the error ratio of a forward (a direction in which a cell is transmitted from the first node to the second node) channel through the state of a backward (a direction in which the cell is transmitted from the second node to the first node) channel and determining the ratio in which the payload of the PDU of an upper layer is converged to the payload of the PDU of a wireless link layer on the basis of the estimated error ratio;
(b) forming a cell to be transmitted through the forward channel by converging the header of the PDU of the upper layer to the header of the PDU of the wireless link layer, adding a first checksum and a first FEC code with respect to the header, converging the payload of the PDU of the upper layer to the payload of the PDU of the wireless link layer according to the convergence ratio determined in the step (a), and adding a second checksum and a second FEC code with respect to the payload;
(c) transmitting the cell formed in the step (b) through the forward channel;
and
(d) re-transmitting a plurality of copies of the cell transmitted in the step (c) when feedback information which indicates that an error exists in the cell transmitted in the step (c) is received through the backward channel.

2 more elements

(a) partitioning an error ratio of the wideband wireless channel into a plurality of sections and estimating the error ratio of a forward (a direction in which a cell is transmitted from the first node to the second node) channel to belong to one of the plurality of predetermined sections through the state of a backward (a direction in which the cell is transmitted from the first node to the second node) channel;
(b) determining the convergence ratio in which the payload of the PDU of an upper layer is converged to the payload of the PDU of a wireless link layer on the basis of the error ratio of the forward channel estimated to belong to one of the plurality of sections in the step (a) and forming a cell according to the convergence ratio, to be transmitted through the forward channel;
(c) newly adjusting allocated bandwidth when the convergence ratio determined in the step (b) changes due to the change of the section to which the error ratio estimated in the step (a) belongs;
(d) transmitting the cell formed in the step (b) through the forward channel;
and
(e) re-transmitting the copy of the cell transmitted in the step (d) when feedback information which indicates that an error exists in the cell transmitted in the step (d) is received through the backward channel.

3 more elements

(a) estimating an error ratio of a forward (a direction in which a cell is transmitted from the first node to the second node) channel through the state of a backward (a direction in which a cell is transmitted from the second node to the first node) channel and determining the ratio in which the PDU of an upper layer is converged to the PDU of a wireless layer on the basis of the estimated error ratio;
(b) transmitting the cell of the PDU of the wireless link layer, which is formed according to the convergence ratio determined in the step (a) through the forward channel;
(c) receiving feedback information on the cell transmitted in the step (b) through the backward channel;
(d) newly adjusting additional bandwidth required for re-transmitting a plurality of copies of the cell transmitted in the step (b) in the same frame using a simultaneous multiple copy method when feedback information that indicates that an error exists in the cell transmitted in the step (b) is received in the step (c);
and
(e) re-transmitting a plurality of copies of the cell transmitted in the step (b) in the same frame using a simultaneous multiple copy method when the feedback information that indicates that an error exists in the cell transmitted in the step (b) is received in the step (c).

3 more elements

Computer readable recording media in which programs for executing the following steps by computers are recorded, in wideband wireless communication for controlling errors in a link layer using an ARQ scheme, in which a wideband wireless channel is used for communication between a first node and a second node;

(a) estimating the error ratio of a forward (a direction in which a cell is transmitted from the second node to the first node) channel through the state of a backward (a direction in which a cell is transmitted from the second node to the first node) channel;
(b) determining a ratio to which the PDU of an upper layer is converged to the PDU of a wireless link layer, on the basis of the error ratio of the forward channel estimated in the step (a);
(c) forming a cell to be transmitted through the forward channel by converging the PDU of the upper layer to the PDU of the wireless link layer according to the convergence ratio determined in the step (b);
(d) transmitting the cell formed in the step (c) through the forward channel;
(e) receiving feedback information on the cell transmitted in the step (d) through the backward channel;
and
(f) re-transmitting a plurality of copies of the cell transmitted in the step (d) according to the ARQ scheme when feedback information that indicates that an error exists in the cell transmitted in the step (d) is received in the step (e).

4 more elements

(a) estimating the error ratio of a forward (a direction in which a cell is transmitted from the second node to the first node) channel through the state of a backward (a direction in which a cell is transmitted from the second node to the first node) channel;
(b) determining a ratio to which the PDU of an upper layer is converged to the PDU of a wireless link layer, on the basis of the error ratio of the forward channel estimated in the step (a);
(c) forming a cell to be transmitted through the forward channel by converging the PDU of the upper layer to the PDU of the wireless link layer according to the convergence ratio determined in the step (b);
(d) transmitting the cell formed in the step (c) through the forward channel;
(e) receiving feedback information on the cell transmitted in the step (d) through the backward channel;
and
(f) re-transmitting the copy of the cell transmitted in the step (d) according to the ARQ scheme when feedback information that indicates that an error exists in the cell transmitted in the step (d) is received in the step (e), wherein the step (f) further includes, when the copy of the cell transmitted in the step (d) is re-transmitted, re-transmitting at least one other copy of the cell transmitted in the step (d), thereby re-transmitting a plurality of copies of the cell transmitted in the step (d) and the step (f) comprises the steps of:
(f1) newly adjusting additional bandwidth required for re-transmitting the plurality of copies of the cell transmitted in the step (d) in the same frame using a simultaneous multiple copy method when feedback information which indicates that an error exists in the cell transmitted in the step (d) is received in the step (e);
and
(f2) re-transmitting the plurality of copies of the cell transmitted in the step (d) in the same frame using a simultaneous multiple copy method.

7 more elements

Dependencies are inferred from the claim text.

Method for controlling errors in link layer in wideband wireless communication and computer readable media therefor

Life of this patent

Method for controlling errors in link layer in wideband wireless communication and computer readable media therefor

Life of this patent

Abstract

Claims37