KR20140013656A - Apparatus and method for increasing transmission efficiency in a communication system - Google Patents

Abstract

The present invention provides a transmitter including an error correction unit generating one or more additional packets by using packets including identification information of one or more receivers; an aggregation unit generating one or more packet aggregations by aggregating the packets and one or more additional packets; and a control unit allocating the identification information of each receiver and information on a group in which the receiver is included to one or more receivers and transmitting the packet aggregations including the packet to be transmitted to each receiver by using the information on the group. [Reference numerals] (100) Header compression unit; (110) Storage unit; (120) Error correction unit; (130) Aggregation unit; (140) Control unit

Description

Apparatus and method for improving transmission efficiency in communication system {APPARATUS AND METHOD FOR INCREASING TRANSMISSION EFFICIENCY IN A COMMUNICATION SYSTEM}

The present invention relates to an apparatus and method for increasing transmission efficiency in a communication system, and to an apparatus and method for increasing VoIP capacity and increasing transmission efficiency and reliability.

As smart phones are widely used, user demand for VoIP (Voice over Internet Protocol) services in a wireless LAN environment is increasing. As a result, researches on increasing the number of users using VoIP at the same access point (AP) at the same time are being conducted. In providing VoIP service, VoIP traffic having bidirectional characteristics is concentrated in downlink data. Therefore, increasing downlink transmission efficiency is important for increasing capacity. Conventional methods for increasing downlink transmission efficiency include a transmission opportunity (TXOP) technique, and the conventional method for increasing downlink transmission efficiency includes an amount of overhead (SIFS, header, ACK frame) added per packet transmission. The transmission efficiency is low, and there is a problem that call quality is degraded due to a low packet transmission success rate.

The present invention relates to an apparatus and method for increasing VoIP capacity, increasing transmission efficiency and reliability in wireless communication.

The present invention also relates to an apparatus and method for reducing power loss of a communication device by reducing packet loss rate and increasing transmission efficiency in providing VoIP services to a plurality of users.

The present invention provides an error corrector for generating at least one additional packet using packets including identification information of at least one receiver; An aggregation unit configured to aggregate the packets and the at least one additional packet to generate at least one packet set; A control unit for allocating at least one receiver identification information of each receiver and information on a group to which each receiver belongs, and transmitting a packet set including a packet to be transmitted to each receiver using the information on the group. It provides a transmitter.

In addition, the present invention comprises an extracting unit for extracting a packet corresponding to the receiver from the packet set corresponding to the group to which the receiver belongs using the identification information of the receiver; An error correction unit for restoring packets included in the packet set; And a control unit configured to receive identification information of the receiver and information on the group from a transmitter, and to determine whether a packet set corresponding to the group is received using the information on the group.

Also. The present invention includes the steps of: assigning at least one receiver identification information of each receiver and information on a group to which each receiver belongs; Generating at least one additional packet using the packets including the identification information; Aggregating the packets and the at least one additional packet to generate at least one packet set; A communication method comprising transmitting a packet set including a packet to be transmitted to the at least one receiver using the information about the group.

In addition, the present invention comprises the steps of receiving from the transmitter identification information of the receiver and information about the group to which the receiver belongs; Checking whether a packet set corresponding to the group is received by using the information about the group; Extracting a packet corresponding to the receiver from a packet set corresponding to the group by using the identification information of the receiver; And restoring packets included in the packet set according to whether a packet corresponding to the receiver is extracted.

The present invention not only reduces the risk and complexity of loss due to synchronization since the transmitter transmits the sequence number and timestamp of the packet through the mini header, but also eliminates the padding process when combined with FEC encoding. Can be.

In addition, the present invention can screen packets received without error in the packet set, so that the increase in the total number of users does not affect the loss rate. In addition, since one packet set serves as a reference for FEC decoding, a separate buffer is not required, and a transmitter does not need to directly inform FEC decoding timing and the total amount of packets.

In addition, since the present invention manages the receiver in a multicast group, the power consumption of the receiver can be reduced, and the channel usage efficiency can be increased. That is, if a multicast group address is allocated according to a possible combination of receivers, only receivers belonging to the group perform packet extraction, thereby reducing power consumption of the receiver.

1 is a view showing the configuration of a transmitter according to an embodiment of the present invention.
2 is a diagram illustrating a configuration of a receiver according to an embodiment of the present invention.
3A and 3B illustrate header compression performed in a transmitter according to an embodiment of the present invention.
4A and 4B illustrate an FEC operation of an error correcting unit performed by a transmitter according to an embodiment of the present invention.
5 is a diagram illustrating a packet set generated by a transmitter according to an embodiment of the present invention.
6A and 6B illustrate grouping of a plurality of receivers in a transmitter according to an embodiment of the present invention.
7 is a view for explaining an operation when a call setup occurs between the transmitter and the receiver according to an embodiment of the present invention.
8 is a flowchart illustrating the operation of a transmitter according to an embodiment of the present invention.
9 is a flowchart illustrating the operation of a receiver according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 is a view showing the configuration of a transmitter 10 according to an embodiment of the present invention.

Referring to FIG. 1, the transmitter 10 according to the present embodiment includes an error correction unit 120, an aggregation unit 130, and a control unit 140, and includes a header compression unit 100 and a storage unit ( 110 may be further included.

The header compression unit 100 compresses a header of a packet received from a network. The header compression may reduce overhead when the length of the header is relatively small because the payload of the packet is small, and may be selectively applied. have.

The storage unit 110 stores the packets and may use a buffer.

The error correction unit 120 may use FEC (Forward Error Correction) to process the packet to recover the loss that may occur during transmission. That is, by paring the packets stored in the storage unit 110 may generate an additional packet (parity packet) for error correction.

The aggregation unit 130 collects a plurality of packets to generate one packet set. One packet set may be one protocol data unit (PDU). Here, the PDU is generated by aggregating a plurality of data frames. For example, the PDU may correspond to an Aggregate-MAC PDU.

The controller 140 groups the plurality of receivers 20 to allocate an address for transmitting a packet set for each receiver 20 in a multicast manner, and allocate a connection identifier (CID) for each receiver 20. Overall control of the transmitter 10.

2 is a diagram illustrating a configuration of a receiver 20 according to an embodiment of the present invention.

Referring to FIG. 2, the receiver 20 according to the present embodiment may include an error corrector 210, an extractor 220, and a controller 230, and may further include a header restoration unit 200.

The header restoration unit 200 restores the compressed header, and the error correction unit 210 corrects an error of the received packet when the receiver 20 does not normally receive the packet. The error correction unit 210 may use the FEC like the transmitter 10 and may correct the packet error by performing FEC decoding.

When the receiver 20 receives the packet set for the receiver 20, the extractor 220 extracts a packet corresponding to the packet set from the packet set, and the controller 230 determines whether the packet set for the receiver 20 is received. Overall control of the receiver 20.

3A and 3B are diagrams for describing header compression performed by the transmitter 10 according to an embodiment of the present invention.

Referring to FIG. 3A, first, the control unit 140 (hereinafter, referred to as a first control unit) of the transmitter 10 sends a CID, which is a unique identifier, to the receiver 20 when the receiver 20 generates a VoIP call. If a plurality of receivers make VoIP calls, CIDs are allocated to each receiver. At this time, the CID may use a length of 1 byte, and the maximum number of CIDs that can be simultaneously allocated in one BSS (Basic Service Set) may be 256.

The first control unit 140 stores the RTP (330), UDP (320), IP (310), LLC (300) headers used in the corresponding VoIP call with the CID, and the header compression unit (100) stores the RTP ( 330, UDP (320), IP (310), LLC (300) headers are replaced with a Mini header (340), where the mini header 340 in the CID 350 and RTP header (330) Each packet may include only a sequence number 360 and a timestamp 370 field, which are parts that change. The format of the mini header 340 is shown in Figure 3b, where the information contained in the MIDI header 340 is used by the receiver 20 to recover the original headers.

The receiver 20 stores the RTP (330), UDP (320), IP (310), and LLC (300) headers corresponding to the CID, and uses the mini header 340 and the CID to receive the original header after receiving the packet. Restore

4A and 4B are diagrams for describing the FEC operation of the error correction unit 120 performed by the transmitter 10 according to an embodiment of the present invention.

Referring to FIG. 4A, the error correction unit 120 (hereinafter, referred to as a first error correction unit) of the transmitter 10 performs FEC encoding on the original packets 400 to generate additional packets 410. If the header of the original packet is compressed, FEC encoding is performed on the compressed packet. In the case of using a high performance RS (Reed-Solomon) code, if a random K packet out of a total of N packets is received, the original packet 400 can be restored. This allows the original packet 400 and additional packets. The reliability may be adjusted according to the ratio of 410. In addition, if the ratio of the FEC code is adjusted, reliability can be adaptively maintained according to the channel environment. The first error correction unit 120 according to the present embodiment can use a systematic FEC code in which the original data remains unchanged. have.

Meanwhile, the error corrector 210 (hereinafter, referred to as a second error corrector) of the receiver 20 corrects an error through the FEC decoding, that is, recovers the lost packet. For FEC decoding, the error corrector 210 of the encoded original packet 400 You need to know the number and order of received packets. The FEC header 450 is used for this purpose, and the first error correction unit 120 attaches the FEC header 450 to each of the original packet 400 and the additional packet 410 after encoding.

The format of the FEC header 450 is shown in FIG. 4B, where the Dec field 420 indicates whether to attempt FEC decoding, the Encoding Symbol Length field 430 indicates the number of original packets, and the encoding The symbol field ID 440 indicates the number of packets. Each of the Dec field 420, the encoding symbol length field 430, and the encoding symbol ID field 440 may be allocated as 1 bit, 7 bit, or 8 bit, and the encoding symbol length field 430 and the encoding symbol ID field ( Since 440 is 7 bits and 8 bits, respectively, up to 128 original packets may be encoded and transmitted at once, and the sum of the original packet 400 and the additional packet 410 may be up to 256.

In addition, when the Dec field 420, which is 1 bit, is set to 0, decoding is not performed. When it is set to 1, decoding may be performed. If the receiver 20 cannot find a packet including the CID corresponding to itself in the packet set for the group to which it belongs, the receiver 20 performs FEC decoding to correct an error regardless of the value set in the Dec field 420, When the packet including the CID corresponding to the packet is found, it may be determined whether to perform decoding according to the setting value of the Dec field 420. As an example, when a plurality of packets including the same CID are included in one packet set, the receiver 20 corresponding to the corresponding CID may extract only some packets and may not find other packets. In this case, if the Dec field is set to 1, since the receiver 20 needs to perform FEC decoding, the receiver 20 may restore all original packets, and may find all packets including the CID corresponding to the receiver.

5 is a diagram for describing a packet set 530 generated by the transmitter 10 according to an exemplary embodiment of the present invention.

Referring to FIG. 5, original packets 510 and additional packets 520 generated through FEC encoding are aggregated into one packet set 530. The receiver 20 decomposes the packet set 530 and extracts only packets corresponding to itself. The packet set 530 includes a plurality of subframes 560, and each subframe 560 includes a separate header in addition to the original packet 510 and the additional packet 520. In FIG. 5, the header added to the subframe includes a Delim field 540 and a MAC field 550. The Delim field 540 is used to distinguish a set of transmitted packets from another set of packets. When a plurality of receivers are grouped, this is to indicate the address of each group.

6A and 6B are diagrams for describing grouping of a plurality of receivers in a transmitter 10 according to an embodiment of the present invention.

The transmitter 10 may transmit a packet corresponding to the receiver 20 directly to the receiver 20 in a unicast manner, and may also transmit a packet set to the receiver 20 in a multicast manner. In order to perform the multicast scheme, the transmitter 10 assigns a group or group address to which the receiver 20 belongs to the receiver 20, and assigns a packet set including a packet to be transmitted to the receiver 20 to the corresponding group address. Can be sent to.

For example, when UE 1 belongs to groups 1, 2, and 4 in FIG. 6A, the transmitter 10 may transmit a packet for UE 1 to any one of group 1, 2, and 4 group addresses. The packet set transmitted to may include packets for other terminals belonging to the group.

Referring to FIGS. 6A and 6B, a method of grouping is described. In the transmitter 10, a group 1 600 includes a terminal 1 and a terminal 2, and a group 2 610 includes a terminal 1 and a terminal 3. Group 3 630 may include a terminal 2, a terminal 3, group 4 (640) includes a terminal 1, a terminal 2, a terminal 3, such that one receiver may be included in a plurality of groups, channel conditions Considering this, receivers with similar channel conditions can be grouped into one group, and can be grouped into two groups, a strong electric field and a weak electric field, as shown in FIG. 6B.

FIG. 7 is a diagram for describing an operation when a call setup occurs between the transmitter 10 and the receiver 20 according to an exemplary embodiment of the present invention.

When the receiver 20 is in idle mode and a call setup occurs with the transmitter 10 (Yes of 700), the transmitter 10 includes a CID for the receiver 20, a group including the receiver 20. Or assign a group address (710), and the receiver 20 stores (720) the assigned CID, group or group address. In this case, the receiver 20 may perform group update when a new group or group address is allocated.

8 is a flowchart illustrating the operation of the transmitter 10 according to an embodiment of the present invention.

Referring to FIG. 8, when a plurality of packets are stored in the storage unit 110 after allocating a CID and a group or group address for at least one receiver 20 (example of 800), For each group, a packet for transmission to the receiver 20 is selected (810). When a packet to be transmitted for each group is selected, the first error correction unit 120 attaches the FEC encoding and the header to the selected packet (820). At this time, the header compression unit 100 compresses the header selected for the packet selected. FEC encoding and header attachment can be performed later.

When the set unit 130 aggregates the packets requested for the FEC encoding and the header to generate a packet set (830), the first controller 140 transmits the packet set generated for each group (840).

9 is a flowchart illustrating the operation of the receiver 20 according to an embodiment of the present invention.

Referring to FIG. 9, when the receiver 20 receives a packet set after allocating a CID and a group or group address corresponding to the receiver 20, the second controller 230 uses the group address included in the packet set to receive the receiver. Check whether a packet set corresponding to 20) is received. When a packet set corresponding to the receiver 20 is received (YES in 900), the second controller 230 checks the CID and FEC header of each packet included in the packet set (910), and in the extractor 220, Extract your own packet.

Looking at the packet extraction process, the second controller 230 checks the CID, if there is a packet corresponding to the receiver 20, that is, if the packet is normally received (Yes of 920), and checks the Dec field of the FEC header, If the Dec field is set to 0 (YES in 930), if the original header of the extracted packet is compressed without performing FEC decoding, the header restoration unit 200 restores the original header (940). On the other hand, if the packet is normally received but the Dec field is set to 1 (NO in 930) or if the packet is not normally received (NO in 920), FEC decoding is performed (950). When all original packets are restored through FEC decoding (Yes of 960), the extractor 220 extracts a packet corresponding to the receiver 20, and if the original header of the extracted packet is compressed, the header restorer ( 200 restores the original header (940). If all original packets are not restored (NO in 960), the second controller 230 reports an error to the transmitter 10 (980).

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the scope of the appended claims, and equivalents thereof.

100: header compression unit 110: storage unit
120: Error Correction 130: Aggregate
140:

Claims (21)

In the transmitter of the communication system,
An error corrector for generating at least one additional packet using packets including identification information of at least one receiver;
An aggregation unit configured to aggregate the packets and the at least one additional packet to generate at least one packet set;
A control unit for allocating at least one receiver identification information of each receiver and information on a group to which each receiver belongs, and transmitting a packet set including a packet to be transmitted to each receiver using the information on the group. Transmitter. The method of claim 1,
A header compression unit for compressing headers of the packets;
And a storage unit for storing the packets. 3. The method of claim 2,
And the compression unit compresses the header of the packets to include at least one of identification information of the at least one receiver, a sequence number corresponding to the packets, and a time stamp in the compressed header. 3. The method according to claim 1 or 2,
The error correction unit generates a header for the packets and the at least one additional packet,
And the header includes at least one of indication information on whether to perform restoration of the packets included in the packet set, information on the number and order of the packets included in the packet set. 3. The method according to claim 1 or 2,
And the error correcting unit generates the at least one additional packet using packets transmitted to receivers belonging to the same receiver group. 3. The method according to claim 1 or 2,
The aggregation unit aggregates packets transmitted to receivers belonging to the same receiver group to generate a packet set.
And the packet set includes information about the receiver group. In the receiver of the communication system,
An extracting unit for extracting a packet corresponding to the receiver from a packet set corresponding to a group to which the receiver belongs using the identification information of the receiver;
An error correction unit for restoring packets included in the packet set;
And a control unit configured to receive identification information of the receiver and information about the group from a transmitter, and determine whether a packet set corresponding to the group is received using the information about the group. 8. The method of claim 7,
And restoring a header when the headers of the packets are compressed. 9. The method according to claim 7 or 8,
And the control unit restores the packets when the extracting unit fails to extract a packet corresponding to the receiver. 9. The method according to claim 7 or 8,
The packets included in the packet set include at least one of indication information on whether to restore the packets, information on the number and order of the packets,
And the error correcting unit restores the packets by using the indication information, the number and the order information. 9. The method according to claim 7 or 8,
The packet set is generated by collecting at least one additional packet generated by using packets including identification information of at least one receiver belonging to the group and packets including identification information of the at least one receiver. A receiver comprising information about. In the communication method of the transmitter of the communication system,
Assigning at least one receiver identification information of each receiver and information on a group to which each receiver belongs;
Generating at least one additional packet using the packets including the identification information;
Aggregating the packets and the at least one additional packet to generate at least one packet set;
And transmitting a packet set including a packet to be transmitted to the at least one receiver using the information about the group. The method of claim 12,
Compressing headers of the packets;
And storing the packets. 14. The method of claim 13,
The compressing may include compressing a header of the packets to include at least one of identification information of the at least one receiver, a sequence number corresponding to the packets, and a time stamp in the compressed header. The method according to claim 12 or 13,
Generating the at least one additional packet comprises generating a header for the packets and the at least one additional packet;
The header includes at least one of indication information on whether to restore the packets included in any one packet set, and information on the number and order of the packets included in the one packet set. . The method according to claim 12 or 13,
The generating of the at least one additional packet comprises generating the at least one additional packet by using packets transmitted to receivers belonging to the same receiver group. The method according to claim 12 or 13,
Generating at least one packet set includes generating a packet set by collecting packets transmitted to receivers belonging to the same receiver group.
And wherein said packet set includes information about said receiver group. In the communication method of the receiver of the communication system,
Receiving identification information of the receiver and information on a group to which the receiver belongs from a transmitter;
Checking whether a packet set corresponding to the group is received by using the information about the group;
Extracting a packet corresponding to the receiver from a packet set corresponding to the group by using the identification information of the receiver;
Restoring packets included in the packet set according to whether a packet corresponding to the receiver is extracted. 19. The method of claim 18,
And restoring the header when the headers of the packets are compressed. 20. The method according to claim 18 or 19,
The packets included in the packet set include at least one of indication information on whether to restore the packets, information on the number and order of the packets,
And restoring the data using the indication information, the number and the order. 20. The method according to claim 18 or 19,
The packet set is generated by collecting at least one additional packet generated by using packets including identification information of at least one receiver belonging to the group and packets including identification information of the at least one receiver. A communication method comprising the information on.

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