JP2005051714A - Packet transmission method and communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a packet transmission method with which receiving properties can be more enhanced. <P>SOLUTION: In the packet transmission method, a header analytic part 2 of a transmitter extracts quality-of-service (QoS) information from a header of an IP packet, and an encoding system determination part 3 determines an encoding system on the basis of the extracted QoS information while associating estimated QoS with corresponding encoding systems in advance. A transmission packet encoding part 5 uses the determined encoding system to encode the IP packet, a control information generation part 4 generates an identification ID to detect a decoding system corresponding to said encoding system at a receiving side, the encoding result and the identification ID are linked and predetermined transmission processing is applied to a result thereof for transmission onto a transmission path by a multiplexing part 6, a modulation part 7 and a radio transmission part 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a packet transmission method for realizing IP packet communication using a mobile communication network, and in particular, an adaptive encoding method according to a required quality of service (QoS). The present invention relates to a packet transmission method to be changed.

  Hereinafter, conventional packet transmission methods will be described (see Non-Patent Document 1 and Non-Patent Document 2 below). Packet retransmission control in the W-CDMA system is performed by RLC (Radio Link Control), which is a sub-layer of the data link layer (L2: Layer 2) in a radio network controller (RNC). The ARQ scheme used in RLC is “Type-I HARQ” of the Selective-Repeat (SR) scheme.

  “Type-I HARQ” is transmitted after performing error detection coding and error correction coding on the information signal sequence on the transmission side. On the other hand, the receiving side performs error correction decoding on the received packet and then performs error detection. If an error is detected, the packet is discarded and a retransmission request is transmitted to the transmission side. On the transmission side, retransmission is performed using the same encoding method based on this retransmission request. By repeating such a procedure until no error is detected, highly reliable communication is performed.

  Note that the base station (NodeB) has a wireless transmission / reception function in the physical layer (L1: Layer 1), and performs an encoding process on a data unit supplied from a MAC (Medium Access Control) which is an L2 sublayer. However, the encoding method is not selected according to the type of transmission data and the transmission path state.

  In the W-CDMA system, high-speed packet radio access technology suitable for data traffic called HSDPA (High-Speed Downlink Packet Access) has been studied by 3GPP, and a method using adaptive modulation / demodulation technology has been standardized.

  In addition, VoIP (Voice over IP) technology that transmits voice / image traffic in IP packets is attracting attention, and in mobile communication networks, IP of radio access network (RAN) and core network (CN) will be studied by 3GPP Has been.

3GPP standard TS25.322 Radio Link Control (RLC) protocol specification 3GPP standard TS25.212 Multiplexing and channel coding

  However, in the conventional packet transmission method, since the ARQ scheme is used, when packet transmission is performed using a radio channel with a high error rate, the number of packet retransmissions increases, and throughput and transmission rate are increased. There was a problem of causing a drop in In particular, there is a possibility of impeding real-time communication such as audio and stream images.

  The present invention has been made in view of the above, and when performing IP packet communication using a mobile communication network, a packet transmission method capable of realizing an improvement in reception characteristics by QoS control required for the packet, It is an object of the present invention to obtain a communication device constituting the mobile communication network.

  In order to solve the above-described problem and achieve the object, the packet transmission method according to the present invention is a packet transmission method for realizing IP packet communication using a mobile communication network, The communication apparatus associates, for example, a header analysis step for extracting service quality information from the header of an IP packet in advance with each assumed service quality and a corresponding encoding method, and the extracted service quality An encoding method determining step for determining an encoding method based on information; an encoding step for encoding the IP packet using the determined encoding method; and a decoding method corresponding to the encoding method on the receiving side. An identification information generation step for generating identification information so that it can be detected, and the encoding result and the identification information are connected, and the result is Characterized in that it comprises a transmission step of transmitting to the transmission line by performing a predetermined transmission process by.

  According to the present invention, for example, the transmitter selects an encoding method according to the characteristics of the transmission data, and the identification result for identifying the decoding method at the receiver is included in the encoding result by the encoding method. To send.

  According to the present invention, the transmitter selects an encoding method according to the characteristics of the transmission data, and transmits the result including the identification information for identifying the decoding method in the encoding result by the encoding method. . As a result, the receiver can select a decoding method in accordance with the characteristics of the transmission data based on the identification information included in the received signal, so that it is possible to improve reception characteristics during normal transmission.

  Hereinafter, embodiments of a packet transmission method, a transmission-side communication device (referred to as a transmitter), and a reception-side communication device (referred to as a receiver) according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration of a transmitter (base station) according to a first embodiment capable of realizing the packet transmission method according to the present invention. The transmitter includes a transmission buffer 1, a header analysis unit 2, An encoding method determination unit 3; a control information generation unit 4 that operates as identification information generation means in claims; a transmission packet encoding unit 5 that operates as encoding means; and a multiplexing unit that operates as transmission means ( MUX) 6, modulation unit 7, and wireless transmission unit 8. The transmission packet encoding unit 5 includes an error control encoding unit 11, a rate matching processing unit 12, and an interleaving processing unit 13.

  FIG. 2 is a diagram showing the structure of an IP packet. This IP packet is composed of a header part such as a TCP header and an IP header and a user data part. The IP header includes a TOS (Type Of Service) field indicating IP service quality, and the TCP header includes a sequence number and an acknowledgment number in retransmission control. Further, the user data part includes data such as voice and image converted to digital information, WEB, E-mail, file download and the like.

  Here, the operation of the transmitter will be described. First, IP packets are sequentially input and stored in the transmission buffer 1. Then, the packet extracted from the transmission buffer 1 is supplied to the header analysis unit 2 and the transmission packet encoding unit 5.

  The header analysis unit 2 extracts the requested quality of service information from the header of the packet and outputs it to the encoding method determination unit 3. The encoding method determination unit 3 determines a method for encoding a packet that satisfies the received quality of service information using a table described later, and notifies the transmission packet encoding unit 5 of the determination.

  In the transmission packet encoding unit 5, first, the error control encoding unit 11 adds an error detection code to the packet using the notified encoding method, and further performs error correction encoding. As the error detection / correction code, for example, the method shown in 3GPP standardization standard TS25.212 is applied. Next, the encoded data sequence output from the error control encoding unit 11 is supplied to the rate matching processing unit 12, and in the rate matching processing unit 12, the bit sequence after the error correction encoding is performed at a constant cycle. Are repeatedly inserted (Repetition), or the bit sequence is thinned out at a fixed period (Puncture). Repetitive insertion of bits and selection of bits to be thinned out are given by the repetition rate (%). For the bit positions to be repeatedly inserted and bit positions to be thinned out, for example, the algorithm shown in 3GPP standard TS25.212 is applied. Is done. Next, the encoded bit sequence output from the rate matching processing unit 12 is rearranged by the interleaving processing unit 13.

  On the other hand, the encoding scheme determination unit 3 also notifies the control information generation unit 4 of the encoding method notified to the transmission packet encoding unit 5, and the control information generation unit 4 uses the pilot bits and the receiver. An identification ID is generated so that the decoding method can be detected, and is output to the multiplexing unit 6.

  Multiplexer 6 concatenates the information received from transmission packet encoder 5 and control information generator 4 and outputs the result to modulator 7. In the modulation unit 7, for example, modulation processing shown in 3GPP standardization standard TS25.213 is performed, and the result is output to the radio transmission unit 8. Finally, the wireless transmission unit 8 transmits a signal after performing band limitation by a root Nyquist filter, D / A (digital / analog) conversion, and frequency conversion to a radio frequency signal via a transmission antenna. Output to.

  FIG. 3 is a diagram illustrating an example of a table referred to by the encoding method determination unit 3. Here, an encoding method corresponding to the service quality information notified from the header analysis unit 2 is recorded. It is assumed that the assumed service quality information and the corresponding encoding method are associated in advance. For example, in packet data requiring low delay quality such as voice, the service quality information 000 is input, and encoding method = {no CRC, convolutional code with coding rate 1/2, rate matching with repetition rate 0.8} is transmitted. Output to the packet encoding unit 5.

  FIG. 4 is a diagram showing a configuration of a receiver (mobile station) capable of realizing the packet transmission method according to the present invention. The receiver includes a radio reception unit 21, a demodulation unit 22, and a claim. The reception packet decoding unit 23, which operates as decoding means, a retransmission control information generation unit 24, and a reception buffer 25 are configured. The received packet decoding unit 23 includes a deinterleave processing unit 31, a rate dematching unit 32, and an error control decoding unit 33.

  First, the radio frequency signal received by the antenna is supplied to the radio receiving unit 21, where frequency conversion to a baseband signal is performed. The demodulator 22 demodulates the received baseband signal, further extracts an identification ID for identifying the decoding method, and searches for an encoding process corresponding to the identification ID from the table shown in FIG. It is assumed that the assumed identification IDs and the encoding methods corresponding to the respective identification IDs are associated in advance.

  In the received packet decoding unit 23, the deinterleaving processing unit 31 and the rate dematching processing unit 32 perform processing reverse to that of the transmitting side interleaving processing unit 13 and the rate matching processing unit 12, and the error control decoding unit 33 further includes Error correction decoding processing corresponding to the encoding processing, calculation of the number of error correction bits for estimating the current transmission path state, and block error detection processing are performed, and the decoding result is output to the reception buffer 25.

  As described above, in this embodiment, the transmitter selects an encoding method according to the characteristics of the transmission data, and transmits the result including the identification ID for identifying the decoding method in the encoding result of the encoding method. It was decided to. As a result, the receiver can select a decoding method according to the characteristics of the transmission data based on the identification ID included in the received signal, so that it is possible to improve reception characteristics during normal transmission.

  The received packet decoding unit 23 outputs the number of error corrections and presence / absence of block error detection to the retransmission control information generating unit 24. In addition, when iterative decoding can be applied in the received packet decoding unit 23, instead of the number of error corrections, the error rate and state transition for each repeated decoding may be obtained, or the number of error corrections described above. Both the error rate for each repeated decoding and its state transition may be obtained.

  The retransmission control information generation unit 24 generates identifiers of ACK (positive ACKnowledgement) and NACK (Negative Acknowledgement) according to the presence / absence of a block error, and stores service quality information at the time of retransmission according to the number of error corrections in the table of FIG. And feed them back to the transmitter.

  For example, when receiving a NACK, the transmitter determines an encoding scheme based on the instructed service quality information, encodes a corresponding packet using the encoding scheme, and retransmits the packet. As described above, in this embodiment, since the transmitter that has received the retransmission request selects the encoding method at the time of retransmission based on the service quality information transmitted from the receiver, the reception characteristics at the time of retransmission are improved. Can be realized.

  As described above, in this embodiment, the transmitter selects an encoding method according to the characteristics of transmission data, and transmits the result including the identification ID for identifying the decoding method in the encoding result of the encoding method. . Then, the receiver selects a decoding scheme based on the identification ID included in the received signal, and feeds back, for example, service quality information at the time of retransmission according to the number of error corrections based on the decoding result by the decoding scheme. Further, the transmitter that has received the retransmission request selects the encoding method at the time of retransmission according to the transmission path state represented by the quality of service information transmitted from the receiver. Thereby, it is possible to improve reception characteristics during normal transmission and retransmission, and as a result, it is possible to suppress an increase in the number of retransmissions.

Embodiment 2. FIG.
FIG. 5 is a diagram showing a configuration of a transmitter (base station) according to a second embodiment capable of realizing the packet transmission method according to the present invention. This transmitter operates as a dividing unit in the claims. A buffer 41 and a plurality of transmission packet encoding units 5 operating as encoding means are provided. In addition, about the structure similar to Embodiment 1 demonstrated previously, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Here, only operations different from those of the first embodiment described above will be described.

  First, IP packets are sequentially input and stored in the transmission buffer 41. In the transmission buffer 41, based on the boundary information between the header part and the data part calculated in the process of extracting the service quality information by the header analysis part 2, the IP packet is converted into the header part and one or more data parts. Each is divided and output to a plurality of transmission packet encoding units 5 (in FIG. 5, the case of dividing into three is described as an example). Here, for example, the IP packet 51 is divided into header information 52 and user data 53 and 54.

  The encoding method determination unit 3 determines the encoding method corresponding to the header part and each data part based on the service quality information notified from the header analysis unit 2. Actually, it is determined with reference to a table corresponding to FIG. 3, for example, based on service quality + data type (header information, user data). The header information 52 and the user data 53 and 54 are encoded by the transmission packet encoding unit 5 and then connected by the multiplexing unit 6.

  As described above, in this embodiment, by dividing and encoding an IP packet, the error resilience strength can be changed for each piece of divided data. Therefore, since encoding is performed according to the characteristics (importance) of the data in the header part / user data part or user data, low-delay transmission of voice or the like can be achieved (codes of information blocks necessary for voice reproduction at least). The transmission line error tolerance can be increased by changing the network.)

  As described above, the packet transmission method and the communication apparatus according to the present invention are useful for IP packet communication using a mobile communication network, and in particular, an adaptive encoding method according to required quality of service (QoS). Suitable for packet transmission that changes

It is a figure which shows the structure of the transmitting apparatus of Embodiment 1 which can implement | achieve the packet transmission method concerning this invention. It is a figure which shows the structure of an IP packet. It is a figure which shows an example of the table referred by the encoding system determination part. It is a figure which shows the structure of a mobile station (receiver). It is a figure which shows the structure of the transmitting apparatus of Embodiment 2 which can implement | achieve the packet transmission method concerning this invention.

Explanation of symbols

1,41 Transmission buffer 2 Header analysis unit 3 Coding method determination unit 4 Control information generation unit 5 Transmission packet coding unit 6 Multiplexing unit (MUX)
7 Modulation unit 8 Wireless transmission unit

Claims (10)

In a packet transmission method for realizing IP packet communication using a mobile communication network,
The sending communication device is
A header analysis step of extracting quality of service information from the header of the IP packet;
Encoding method determining step for associating each assumed service quality with a corresponding encoding method in advance and determining an encoding method based on the extracted service quality information;
An encoding step of encoding the IP packet with the determined encoding method;
An identification information generating step for generating identification information so that a decoding method corresponding to the encoding method can be detected on the receiving side;
A transmission step of concatenating the encoding result and the identification information, performing a predetermined transmission process on the result, and transmitting the result to a transmission path;
A packet transmission method comprising: The communication device on the receiving side
Encoding corresponding to the identification information by associating each assumed identification information with a corresponding encoding scheme in advance, extracting the identification information from the received signal after demodulation by performing a predetermined reception process A demodulation step for retrieving a scheme;
A decoding step of decoding the received signal after demodulation by a decoding method corresponding to the encoding method, and outputting the decoding result and a predetermined transmission path state obtained by a decoding process;
Retransmission control information generating step of feeding back information indicating whether or not normally received, and service quality information at the time of retransmission according to the predetermined transmission path information, to the transmission side;
The packet transmission method according to claim 1, further comprising:   As the predetermined transmission path state, the number of error corrections, if iterative decoding can be applied in the decoding step, the error rate for each repeated decoding and its state transition, or the number of error corrections and the error rate for each repeated decoding The packet transmission method according to claim 2, wherein both of the data and the state transition thereof are obtained. The transmitting communication device is
When receiving information indicating that reception was not successful from the receiving side, the encoding method at the time of retransmission is determined based on the quality of service information notified at the same time, and the corresponding packet is encoded by the encoding method. Resending step to resend,
The packet transmission method according to claim 1, 2, or 3. In a packet transmission method for realizing IP packet communication using a mobile communication network,
The sending communication device is
A header analysis step of extracting quality of service information from the header of the IP packet;
A dividing step of dividing the IP packet into a header and one or more data parts based on boundary information between a header and a data part obtained in the process of extracting service quality information in the header analysis step;
Assume that each assumed service quality and the corresponding encoding method are associated in advance and correspond to the divided header and each data part based on the extracted service quality information and the divided data type An encoding method determining step for individually determining the encoding method;
An encoding step for individually encoding the header and each data portion after division by the determined encoding method;
An identification information generating step for generating identification information so that a decoding method corresponding to the encoding method can be detected on the receiving side;
A transmission step of concatenating the encoding result and the identification information, performing a predetermined transmission process on the result, and transmitting the result to a transmission path;
A packet transmission method comprising: In a communication device on the transmission side that realizes IP packet communication using a mobile communication network,
Header analysis means for extracting service quality information from the header of the IP packet;
Encoding method determining means that associates in advance each assumed service quality and the corresponding encoding method, and determines the encoding method based on the extracted service quality information;
Encoding means for encoding the IP packet with the determined encoding method;
Identification information generating means for generating identification information so that a receiving side can detect a decoding method corresponding to the encoding method;
Transmitting means for concatenating the encoding result and the identification information, performing a predetermined transmission process on the result, and transmitting the result to a transmission path;
A communication apparatus comprising:   Furthermore, when receiving information indicating that reception has failed from the receiving side, the encoding method at the time of retransmission is determined based on the quality of service information notified at the same time, and the corresponding packet is encoded using the encoding method. The communication apparatus according to claim 6, wherein retransmission control is performed by making the communication information into a network. In a communication device on the transmission side that realizes IP packet communication using a mobile communication network,
Header analysis means for extracting service quality information from the header of the IP packet;
A dividing means for dividing the IP packet into a header and one or a plurality of data parts based on boundary information between a header and a data part obtained in the process of extracting service quality information in the header analysis step;
Assume that each assumed service quality and the corresponding encoding method are associated in advance and correspond to the divided header and each data part based on the extracted service quality information and the divided data type An encoding method determining means for individually determining the encoding method;
An encoding means for individually encoding the header and each data portion after the division by the determined encoding method;
Identification information generating means for generating identification information so that a receiving side can detect a decoding method corresponding to the encoding method;
Transmitting means for concatenating the encoding result and the identification information, performing a predetermined transmission process on the result, and transmitting the result to a transmission path;
A communication apparatus comprising: In a communication device on the receiving side that realizes IP packet communication using a mobile communication network,
Each identification information sent from the transmission side for detecting the decoding method corresponding to the encoding method is associated with the corresponding encoding method in advance, and subjected to demodulation by performing a predetermined reception process. Demodulation means for extracting the identification information from a later received signal and searching for an encoding scheme corresponding to the identification information;
Decoding means for decoding the received signal after demodulation by a decoding method corresponding to the encoding method, and outputting the decoding result and a predetermined transmission path state obtained by decoding processing;
Retransmission control information generating means for feeding back information indicating whether or not normally received, and service quality information at the time of retransmission according to the predetermined transmission path information, to the transmission side;
A communication apparatus comprising:   As the predetermined transmission path state, the number of error corrections, if iterative decoding can be applied in the decoding step, the error rate for each repeated decoding and its state transition, or the number of error corrections and the error rate for each repeated decoding The communication apparatus according to claim 9, wherein both the information and the state transition thereof are obtained.

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