CN102938679B - Method for Detecting Wireless Transmission Errors - Google Patents

Abstract

The invention discloses a method for detecting wireless transmission errors, which comprises the following steps: the transmission end processes specific data according to a specific transmission mode to generate encrypted data; generating a verification code according to the specific transmission mode; providing a protocol data unit according to the encrypted data and the verification code; after transmitting the protocol data unit, the receiving end decodes the protocol data unit, and judges whether the decoded data of the protocol data unit is in accordance with the verification code, thereby detecting the wireless transmission error.

Description

Method for Detecting Wireless Transmission Errors

technical field

The invention relates to a method for detecting errors in wireless transmission.

Background technique

The third-generation mobile communication system adopts the wireless access method of Wideband Code Division Multiple Access (WCDMA), which can provide high spectrum utilization rate, unlimited coverage and high-quality, high-speed multimedia data transmission , which can meet the quality of service (QoS) of various requirements at the same time, provide flexible and diversified two-way transmission services, and provide better communication quality to effectively reduce the call drop rate (Call Drop).

Regarding multimedia broadcast and multicast services, the 3rd Generation Partnership Project (3GPP) has defined their operation methods in detail in related specifications, and the following is only a brief description. First of all, in terms of Universal Mobile Telecommunications System (UMTS), the third generation mobile communication system includes User Equipment (UE), UMTS Terrestrial Radio Access Network (UMTS Terrestrial Radio Access Network, UTRAN) and core The network (Core Network, CN) has three parts. In the WCDMA system, the protocol structure of the wireless interface includes the physical layer (Physical Layer) L1, the data link layer (Data LinkLayer) L2, and the network layer (Network Layer) L3. The communication protocol used in its second layer data link layer L2 includes access stratum (Access Stratum, AS) and non-access stratum (Non-Access Stratum, NAS). The access layer includes radio resource control (Radio Resource Control, RRC), radio link control (Radio Link Control, RLC), media access control (Media Access Control, MAC), packet data convergence protocol (Packet Data Convergence Protocol, PDCP) , Broadcast and Multicast Control (Broadcast/Multicast Control, BMC) and several sublayers with different functions. The data is encapsulated correspondingly in each sublayer, and the data received by the sublayer from the upper layer is regarded as the service data unit (Service Data Unit, SDU) of this sublayer, which becomes a protocol data unit (Protocol Data Unit) after sublayer encapsulation. , PDU), and then passed to the next sub-layer. The processing procedure received by the receiving end is roughly the reverse of that of the transmitting end, and the sublayer will perform corresponding processing on the data to decapsulate it. The functions and operations of the above-mentioned related sub-layers are well known in the industry and will not be further described here.

The main function of the RLC communication protocol is to provide different transmission quality processing for the third-generation mobile communication system. According to different transmission quality requirements, different cutting, transmission, retransmission and combination processing are performed for the transmitted data or control commands. In the third generation mobile communication system, four different transmission quality levels are defined, namely Conversational, Streaming, Interactive and Background. The RLC layer performs packet segmentation and packetization in the following three ways to meet different transmission quality requirements:

1. Transparent mode (Transparent Mode, TM): according to the length of the packet, it is directly cut and divided without any other processing. Transparent mode is suitable for services that require immediate transmission, such as voice calls.

2. Unacknowledged Mode (Unacknowledged Mode, UM): In addition to cutting and packetizing, an appropriate header (Header) is added before each packet to assist the receiving end in checking the packet sequence and discarding error packets. Unacknowledged mode is suitable for services that require both immediate transmission and packet order, such as Voice over Internet Protocol (VoIP) communication or VideoPhone.

3. Acknowledged Mode (Acknowledged Mode, AM): In addition to cutting packets and appending packet sequence headers, the receiving end needs to perform sequence check, duplicate detection, and retransmission processing for each packet to ensure that all packets can be correctly transmitted. reach the receiving end. Confirmation mode is suitable for services that do not have high requirements for immediate transmission but high data accuracy, such as web browsing, email or file transfer services.

During wireless transmission, user data and some signaling information are prone to interference and errors, so they must be protected by data encryption. In the known third generation mobile communication system, the relevant data is encrypted through encryption (Ciphering) operation between the mobile equipment (Mobile Equipment) and the radio network controller (RadioNetwork Controller). FIG. 1 is a schematic diagram of data encryption and decryption performed by a known third-generation mobile communication system. The left side of the dotted line represents the transmission end, which first sends the encryption key (Ciphering Key) CK, count (Count) COUNT-C, bearer identifier (Bearer Identifier) BEARER, direction identifier (Direction Identifier) DIRECTION and length indicator (Length Indicator) LENGTH, etc. The parameters are obtained through the F8 algorithm to obtain multiple Keystream Blocks (Keystream Block) KEYSTREAM, and then the exclusive-OR operation is performed on the Keystream Block KEYSTREAM and the Plain Text (Plain Text) block PLAIN-TEXT to obtain Cipher Text block CIPHER-TEXT. The right side of the dotted line represents the receiving end, which can perform an XOR operation on the keychain block KEYSTREAM and the received ciphertext block CIPHER-TEXT to decrypt the original plaintext block PLAIN-TEXT.

During a voice call, the wireless communication device is in the transparent mode. At this time, the PDU generated after encrypting the data only contains voice data without other additional information, and the receiving end cannot verify whether the received data is correct. If there is interference during the transmission process, or there is an asynchronous situation between the user end and the network end, the user may hear noise all the time during the call.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for detecting wireless transmission errors so as to improve communication quality.

In order to solve the above technical problems, the present invention provides a method for detecting wireless transmission errors, including: in a specific transmission mode, processing specific data to generate encrypted data; generating a verification code according to the specific transmission mode; according to the encrypted data and the verification code code to provide the protocol data unit; and after transmitting the protocol data unit, decoding the protocol data unit, and judging whether the decoded data of the protocol data unit matches the verification code.

The present invention can be applied to wideband code division multiple access systems, and the RLC layer will add a frame check sequence field in the protocol data unit to store information related to encrypted data, so that the receiving end can verify whether the content of the transmitted data is correct , so the corresponding error control program can be executed when a wireless transmission error is detected, thereby improving the communication quality.

Description of drawings

FIG. 1 is a schematic diagram of data encryption and decryption performed by a known third-generation mobile communication system.

Fig. 2 is a flowchart of a method for detecting wireless transmission errors in the present invention.

3A-3C are schematic diagrams of the operation of the RLC layer in WCDMA of the present invention.

Wherein, the reference signs are explained as follows:

TM_PDU transparent mode protocol data unit

UM_PDU unacknowledged mode protocol data unit

AM_PDU Acknowledgment Mode Protocol Data Unit

210～250 steps

Detailed ways

Fig. 2 is a flow chart of a method for detecting wireless transmission errors in the present invention, which includes the following steps:

Step 210: The transmitter processes the specific data to generate encrypted data.

Step 220: The transmitting end provides the PDU according to the encrypted data and the verification code, and then transmits the PDU to the receiving end.

Step 230: After receiving the PDU, the receiving end decodes the PDU, and judges whether the content of the decoded data conforms to its verification code; if yes, execute step 240; if not, execute step 250.

Step 240: The receiver executes an error control program.

Step 250: end.

In the present invention, the transmitting end and the receiving end may be the user end or the network end respectively. That is, the present invention can detect wireless transmission errors between UEs, between networks, or between UEs and networks.

In step 210, the transmitting end can process the specific data according to the operation mode to generate corresponding encrypted data. For example, in transparent mode, data processing can include cutting and packaging service data units from the upper layer to generate encrypted data; in non-confirmation mode, data processing can include service data from the upper layer The unit is cut and packaged to generate encrypted data, as well as corresponding additional information such as sequence number (sequence number), length indication, padding (PAD), etc.; in confirmation mode, data processing can include The service data unit is cut and packaged to generate encrypted data, as well as corresponding additional information such as sequence number, length indication, padding or status protocol data unit (status PDU).

In step 220, the transmitting end provides the PDU according to the encrypted data and the verification code. In the embodiment of the present invention, a frame check sequence (Frame Check Sequence, FCS) can be generated according to a cyclic redundancy check (Cyclic Redundancy Check, CRC) as a verification code. The frame check sequence can be generated according to data encryption methods in different operation modes, for example, it includes information such as encrypted data content, length indication, or padding. The frame check sequence is usually a multi-bit cyclic redundancy check code, which can be used to verify whether the data field or the header field of the protocol data unit is correct. The detailed operation of the cyclic redundancy check is well known to those with ordinary knowledge in the related art, and will not be repeated here.

According to the specifications formulated by the 3rd Generation Mobile Communications Alliance, the PDU of the transparent mode includes a data field, while the PDU of the unacknowledged mode and the acknowledged mode include a data field and a header field. 3A-3C are schematic diagrams of the operation of the RLC layer in the present invention. Fig. 3A shows a transparent mode protocol data unit TM_PDU, Fig. 3B shows an unacknowledged mode protocol data unit UM_PDU, and Fig. 3C shows an acknowledged mode protocol data unit AM_PDU.

In FIG. 3A , the transparent mode protocol data unit TM_PDU transmitted in step 220 includes a data field DATA and a frame check sequence field FCS. After receiving the service data unit from the upper layer in the transparent mode, the encrypted data after data segmentation and packetization will be stored in the data domain DATA, and the verification code containing the data encryption information will be stored in the frame check sequence domain FCS.

In FIG. 3B , the unacknowledged mode protocol data unit UM_PDU transmitted in step 220 includes a data field DATA, a header field UM_Header and a frame check sequence field FCS. After receiving the service data unit from the upper layer in non-confirmation mode, the encrypted data after data cutting and packaging will be stored in the data field DATA, and additional information such as sequence number, length indication or padding will be stored in the corresponding Header field UM_Header, and store the verification code containing data encryption information into the frame check sequence field FCS.

In FIG. 3C , the acknowledgment mode protocol data unit AM_PDU transmitted in step 220 includes a data field DATA, a header field AM_Header and a frame check sequence field FCS. After receiving the service data unit from the upper layer in the confirmation mode, the encrypted data after data cutting and packaging will be stored in the data field field DATA, and the sequence number, length indication, padding or status protocol data unit will be appended. The information is stored in the header field AM_Header, and the verification code containing data encryption information is stored in the frame check sequence field FCS.

In step 230, the receiving end decodes the PDU and determines whether the content of the decoded data conforms to the verification code. In the transparent mode, the receiving end can decode the PDU according to the MAC layer communication protocol; in the unacknowledged mode or the acknowledged mode, the receiving end can decode the PDU according to the RLC layer communication protocol.

If it is determined that the decoded data of the PDU and the verification code are inconsistent with each other, the receiving end executes step 240 to execute an error control procedure. The present invention can use common error control programs in the field of wireless communication, such as forward error correction (Forward Error Correction, FEC), automatic repeat request (Automatic Repeat Request, ARQ) or hybrid automatic repeat request (Hybrid Automatic Repeat Request, HARQ) and so on. Forward error correction is a single-direction error control mechanism. When the receiving end determines that the data is wrong, it will correct it by itself. If it cannot be corrected, it will discard it without notifying the transmitting end. The automatic retransmission request is an error control mechanism for two-way transmission. When the receiving end finds a data error, it will notify the transmitting end and request to retransmit the data, so it can provide high reliability. HARQ combines the advantages of the above two, while ensuring transmission reliability, it can also avoid reducing overall system performance due to excessive retransmission in a wireless environment.

The present invention can be applied to wideband code division multiple access systems, and the RLC layer will add a frame check sequence field in the protocol data unit to store information related to encrypted data, so that the receiving end can verify whether the content of the transmitted data is correct , so the corresponding error control program can be executed when a wireless transmission error is detected, thereby improving the communication quality.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the claims of the present invention shall fall within the scope of the present invention.

Claims (7)

1. detect a method for wireless transmission mistake, comprise:

Under specific transmission mode, process particular data is to produce enciphered data;

Identifying code is produced according to this specific transmission mode;

Protocol Data Unit is provided according to this enciphered data and this identifying code; And

After this protocol Data Unit of transmission, this protocol Data Unit of decoding, and judge whether the decoded data of this protocol Data Unit and this identifying code are consistent, Qi Zhong ﹕

This specific transmission mode is according to the one in the transparent mode of wireless chain control layer communication protocol, Unacknowledged Mode or affirmation mode; And

This particular data is the service data unit that last layer transmits.

2. the method for claim 1, is characterized in that, comprises:

Cyclic redundancy check (CRC) is used to produce Frame Check Sequence using as this identifying code.

3. the method for claim 1, is characterized in that, this identifying code comprise produce according to this specific transmission mode encrypted digital content, Length Indication or cover information.

4. the method for claim 1, is characterized in that, comprises:

If when this decoded data and this identifying code do not meet, execution error control program.

5. method as claimed in claim 4, is characterized in that, this error control procedure comprises corrects this decoded data or requires data retransmission.

6. the method for claim 1, is characterized in that, when this specific transmission mode is this transparent mode, the method to be decoded this protocol Data Unit according to media access control layer communication protocol.

7. the method for claim 1, is characterized in that, when this specific transmission mode be this Unacknowledged Mode or this affirmation mode time, the method to be decoded this protocol Data Unit according to this wireless chain control layer communication protocol.