RU2216101C2 - Data transmission device and method for mobile communication system with allocated control channel - Google Patents

Abstract

FIELD: mobile communication systems including those for data transmission through allocated control channel. SUBSTANCE: code-division multiple access communication system incorporates allocated control channel capable of effective transfer of control messages between base station and mobile station. Transmitting device controller incorporated in allocated control channel estimates frame length of message to be transferred and yields signal for selecting frame corresponding to frame length found by estimation. Message generator produces frame data on message to be transferred according to frame selection signal. Transmitter functions to stretch frame data and to transmit them over allocated control channel. Compressor incorporated in receiving device of allocated control channel functions to compress signal received. First message receiver provides for deinterleaving and decoding of compressed signal related to first frame length for outputting first message and detects first cyclic redundancy code corresponding to decoded signal. Second message receiver provides for deinterleaving and decoding of compressed signal related to second frame length for outputting second message and detects second cyclic redundancy code corresponding to decoded signal. Controller functions to select first or second message in compliance with results of detection of first and second cyclic redundancy codes. EFFECT: enhanced throughput capacity, reduced traffic delay. 27 cl, 21 dwg

Description

Technical field
The present invention relates to a device and method for transmitting data for a mobile communication system and, in particular, to a device and method for transmitting control information for servicing data transmission using a dedicated control channel in a mobile communication system that provides multimedia data transmission service.

Description of the prior art
Currently, in mobile communication systems, CDMA (Code Division Multiple Access) technology is increasingly used. In order to transmit control signals for call processing, the conventional CDMA mobile communication system operating in the APS / AEP BC-95 standard (Internal Standard-95 of the Telecommunications Manufacturers Association / Electronic Industry Association, TIA / EIA IS-95) multiplexes the control signals to the traffic channel designed to transmit voice information. The traffic channel is characterized by a fixed frame length of 20 ms, and the signal traffic with control signals transmits the entire frame message using the intermittent transmission technology or uses the frame together with the main user traffic through the intermittent transmission technology to transmit control signals.

 Although this signaling technology is available for a CDMA mobile communication system operating in the IS-95 standard that provides only voice service, it is not available for a CDMA mobile communication system that provides multimedia data exchange services including, in addition to voice services, packet exchange services data. This means that the CDMA mobile communication system designed to serve the exchange of multimedia data must include channels for voice and data services in order to flexibly assign channels at the request of users. For this, the CDMA mobile communication system includes a voice traffic channel (or a primary channel) and a packet traffic channel (or an auxiliary channel).

 In order to service the exchange of data on the main channel (or channel of voice traffic) and the auxiliary channel (or channel of packet traffic), the conventional CDMA mobile communication system is forced to support the main channel for transmitting a control signal even when communication between the base station and the mobile station is not performed , which leads to wasting bandwidth of the channel and radio channel. In addition, in the conventional CDMA mobile communication system, a single fixed frame length of 20 ms is used, regardless of the size of the message to be transmitted, which can lead to a decrease in throughput and an increase in traffic delay.

Summary of invention
So, the present invention is based on the task of creating a structure of a dedicated control channel capable of efficiently transmitting control messages between the base station and the mobile station, top-level call control messages and control messages for communication on the packet traffic channel by providing a dedicated control channel with which the mobile a station could only transmit a control signal to a base station in a CDMA mobile communication system, and the way this structure works.

 Another objective of the present invention is to provide a device and method for generating and transmitting a control message having a variable frame length in accordance with the size of the communication control message in a CDMA mobile communication system using a dedicated control channel.

 Another objective of the present invention is to provide a device and method for adaptive periodic transmission of a control message on a dedicated control channel in accordance with the absence / presence of a control message in a mobile communication system using a dedicated control channel.

 Another objective of the present invention is the provision of a device and method for processing frame data, in which the receiving device receives frame data transmitted in the discontinuous transmission mode, detects the data energy of the received frame, and determines the absence / presence of an effective frame to process the frame data in accordance with the determination made.

 Another objective of the present invention is to provide a device and method for processing frame data, in which the receiver receives frame data transmitted in discontinuous transmission mode, detects the energy of the data of the received frame and determines the absence / presence of an effective frame to process the received frame data in accordance with the result of frame detection and the result of error detection.

 To solve the aforementioned problem in a CDMA cellular communication system, a dedicated control channel transmitter is provided. In the transmitting device, the controller determines the frame length of the message to be transmitted, and provides a frame selection signal corresponding to the frame length obtained by determining to transmit a message having at least two different frame lengths. The message generator generates frame data of the message to be transmitted in accordance with the frame selection signal. The transmitter stretches the frame data and transmits the stretched frame data over a dedicated control channel.

 The message generator includes a CRC generator (cyclic redundancy code, CRC) for generating CRC bits for a message characterized by a frame length determined in accordance with a frame selection signal, and for adding CRC bits to the message, a tail bit generator for generating tail bits and to add the generated tail bits to the output of the CEC generator, a channel encoder designed to encode frame data to which tail bits are added with a coding coefficient, and an interleaver for interleaving the encoded message with a unit of the frame length determined in accordance with the frame selection signal.

 Preferably, the message frame includes a 5 ms frame and a 20 ms frame, and the message includes a user message, a signaling message, and a MAC (Media Access Control) message.

 In addition, the transmitter of the dedicated control channel may include message generators in an amount equal to the number of message frame lengths to be transmitted, and corresponding message generators generate frame data of a corresponding length.

 The controller includes a device for generating an output signal control signal to perform discontinuous transmission in the absence of messages to be transmitted, and the transmitter includes a path controller for controlling an output signal of a dedicated control channel from the output signal control signal. In this case, the path controller comprises a gain controller whose output gain is set to zero by the output control signal.

 In accordance with one aspect of the present invention, a dedicated control channel receiver includes a compressor for compressing a received signal; a first message receiver for reverse interleaving and decoding a compressed signal having a first frame length, for issuing a first message and for detecting a first CRC corresponding to a decoded signal; a second message receiver for deinterleaving and decoding the compressed signal having a second frame length, for issuing a second message and for detecting a second CRC corresponding to the decoded signal; and a controller for selecting between the first and second messages in accordance with the first and second CRC detection results obtained by the first and second message receivers.

 The controller includes a frame decision block for analyzing the first and second CEC detection results for deciding on the frame length of the received message and issuing a decision signal for the frame length, and a selector for selecting one of the decoded signals output from the first and second message receivers, in accordance with a frame decision signal.

 In accordance with another aspect of the present invention, a dedicated control channel receiver includes a compressor for compressing a received signal; a frame detector for detecting the energy of a compressed signal having a first and second frame lengths, and for issuing a first and second frame detection signals in accordance with the detection results; a first message receiver for deinterleaving and decoding a compressed signal having a first frame length to provide a first message; a second message receiver for reverse interleaving and decoding the compressed signal, characterized by a second frame length, for issuing a second message; and a controller for selecting between the first and second messages in accordance with the first and second detection results.

 The frame detector comprises the first and second frame detectors. The first frame detector has, as a reference value, a minimum energy value of an effective frame of 5 ms length and compares the energy value of a received frame message with a minimum energy value of an effective frame of 5 ms in order to generate a first frame detection signal when the energy value of a received frame message is higher than the minimum energy value 5 ms effective frame. The second frame detector has a minimum value of an effective frame energy of 20 ms as a reference value and compares the energy of the received frame message with a minimum energy value of an effective frame of 20 ms in order to generate a second frame detection signal when the energy value of the received frame message is higher than the minimum effective energy value frame length of 20 ms.

 In accordance with another aspect of the present invention, the receiving device of the dedicated control channel includes a compressor for compressing the signal received on the dedicated control channel; a first frame detector for detecting the energy of a compressed signal having a first frame length to provide a first frame detection signal in accordance with the detection result; a second frame detector for detecting the energy of a compressed signal having a second frame length to provide a second frame detection signal in accordance with the detection result; a first message receiver for deinterleaving and decoding a compressed signal having a first frame length, for outputting a first message and for detecting a first CRC corresponding to a decoded signal, for outputting a first CRC detection signal; a second message receiver for deinterleaving and decoding the compressed signal having a second frame length, for issuing a second message and for detecting a second CRC corresponding to the decoded signal, for issuing a second CRC detection signal; and a controller for selecting between the first and second messages in accordance with the first and second results of detecting the frame and the first and second results of detecting the CRC.

 The controller comprises a decision block on the frame and a selector. The frame decision block analyzes the first and second CEC detection signals and the first and second frame detection signals, having received the second CEC detection signal and the second frame detection signal, determines that the received frame has a second frame length, having received the first CEC detection signal and the first detection signal frame, determines that the received frame has a first frame length, and, having received other signals to detect the CRC and the frame, determines that the received frame is an erroneous frame. Having received either the first or second decision signal along the frame length, the selector outputs, respectively, one of the decoded signals issued by the first and second message receivers, and, having received the decision signal about the presence of an erroneous frame, controls the output of the decoded signal.

 In addition, the frame decision block determines the absence of reception of any frame in the absence of reception of the first and second frame detection signals, as well as the first and second CRC detection signals.

Brief Description of the Drawings
The above and other tasks, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which like parts are denoted by like numbers. In the drawings:
FIG. 1A is a flowchart illustrating a connection procedure;
FIG. 1B is a flowchart illustrating a disconnection procedure;
2A is a diagram illustrating a frame structure of a first length for a dedicated control channel according to the present invention;
FIG. 2B is a diagram illustrating a frame structure of a second length for a dedicated control channel according to the present invention;
FIG. 2B is a diagram illustrating a structure of a second-length traffic frame for a dedicated control channel according to the present invention;
FIG. 3A is a time distribution diagram illustrating a transmission time when a second length frame is used for a dedicated control channel in a mobile communication system of the present invention;
FIG. 3B is a time distribution diagram illustrating a transmission time when a first-length frame is used for a dedicated control channel in a mobile communication system of the present invention;
4 is a flowchart illustrating procedures for assigning and releasing a dedicated control channel and a dedicated traffic channel in a mobile communication system in accordance with the present invention;
FIG. 5A and 5B are diagrams illustrating a direct dedicated control channel transmitter in a mobile communication system in accordance with the present invention;
6 is a diagram illustrating a reverse dedicated control channel transmission apparatus in a mobile communication system in accordance with the present invention;
FIG. 7A and 7B are diagrams illustrating receivers of a dedicated control channel in a mobile communication system in accordance with various embodiments of the present invention;
FIG. 8 is a diagram illustrating a receiver of a dedicated control channel in a mobile communication system equipped with a frame detector in accordance with another embodiment of the present invention;
FIG. 9 is a diagram illustrating a receiver of a dedicated control channel in a mobile communication system equipped with separate frame detectors, in accordance with yet another embodiment of the present invention;
FIG. 10 is a flowchart illustrating a method for detecting an effective frame in a frame detector (740) shown in FIG. 8 and in a first frame detector (743) shown in FIG. 9;
FIG. 11 is a flowchart illustrating a method for detecting an effective frame in a second frame detector (741) shown in FIG. 9;
FIG. 12 is a flowchart illustrating a method for determining a frame length and its presence in a decision block (730) for a frame shown in FIG. 8;
FIG. 13 is a flowchart illustrating a method for determining a frame length and its presence in a decision block (750) on the frame shown in FIG. 9;
FIG. 14 is a diagram illustrating a receiver of a dedicated control channel in a mobile communication system equipped with separate frame detectors, in accordance with yet another embodiment of the present invention; and
FIG. 15 is a diagram illustrating a simulation result for control messages having frame lengths of 5 ms and 20 ms according to the present invention.

Detailed Description of Preferred Embodiments
The CDMA mobile communication system in accordance with the present invention further includes a dedicated control channel (CCU), with which the mobile station can exclusively transmit the control signal to the base station. A dedicated control channel is a control channel that is used exclusively for transmitting a control signal between a base station and a separate mobile station. In particular, a dedicated control channel is used in signal exchange to control communications on a traffic channel.

 In addition, when transmitting a control signal using a dedicated control channel, the new CDMA mobile communication system uses frames of different sizes, namely the first and second lengths, in accordance with the size of the control signal. Thus, with a small size of the control signal, the system generates and transmits a frame having a first length; with a large size of the control signal, the system generates and transmits a frame having a second length.

 In addition, the CDMA mobile communication system determines the presence / absence of a control message to be transmitted in order to control the output signal (suppress it) of the dedicated control channel in the absence of any control message to be transmitted, and to form the output signal path for the dedicated control channel only when the presence of a control message to be transmitted.

 Now consider a mobile communication system mdcr, corresponding to the present invention.

 A dedicated control channel is used in messaging to control communication on the traffic channel between the base station and the mobile station. Before describing the structure of the dedicated control channel, we list the channels used in the new CDMA mobile communication system and their purpose.

 As for the direct communication line, which is an RF (high frequency) communication line for transmitting a signal from a base station to a mobile station, the common channels include a pilot channel, a clock channel and a paging channel (or common control channel), and user channels include a dedicated control channel, a voice traffic channel, and a packet traffic channel. Regarding the reverse link, which is an HF link for transmitting a signal from a mobile station to a base station, the common channel includes an access channel (or common control channel), and the user channels include a pilot channel allocated control channel, voice traffic channel and packet traffic channel.

 Therefore, the channel transceiver of the base station and the mobile station in the CDMA mobile communication system consists of a pilot channel transceiver used to estimate the channel gain and phase and to capture and transmit a cell, a paging channel transceiver for initial synchronization and provision information about the base station, information about the access channel and information about neighboring cells, the transceiver of the dedicated main channel, for transmitting / receiving voice data, a transceiver of a dedicated auxiliary channel for transmitting / receiving packet data, and a transceiver of a dedicated control channel for transmitting / receiving control messages regarding a connection / disconnection state and communication on a dedicated main channel and a dedicated auxiliary channel .

 Table 1 shows which channels are used on the forward link and on the reverse link for a particular type of service.

 A CDMA mobile communication system may have an idle mode, a voice mode (or a voice traffic channel use mode), a packet reservation mode (or a packet traffic channel use mode), and a combined mode combining the above modes in accordance with a service state. Among the above-mentioned modes, a dedicated control channel is preferably used for a call providing service for a packet reservation mode (i.e., service using a packet traffic channel). In this case, a dedicated control channel is assigned to mobile stations using packet data service. However, as an exception, the dedicated control channel can be used in conjunction with the voice traffic channel for high-quality voice service. In this case, not only a separate mobile station can use the dedicated control channel, but several mobile stations can share.

 Call processing for packet data service is compatible with the IS-95 call processing method. When connecting to service packet data transmission, an initialization message and a channel assignment message corresponding to IS-95 are used, modified to support packet data service; when disconnected, a command message corresponding to IS-95, modified to support packet data service, is used to service packet data transmission. As an example, FIGS. 1A and 1B show, respectively, a connection procedure and a disconnection procedure carried out at the request of a mobile station.

 According to FIG. 1A, in step 111, the mobile station is synchronized with the base station via the clock channel, and in step 113, the base station sends the parameters of the system, access channel, and neighboring cell to the mobile station via the paging channel. Then, at step 115, the mobile station issues an initialization message on the access channel. At step 116, the base station acknowledges the receipt of the initialization message via the paging channel and, at step 117, assigns traffic channels through the paging channel. When traffic channels are assigned channels for communication between the base station and the mobile station, the system, in step 121, enters the communication state, and dedicated control channels for the forward link and the reverse link are also assigned.

 According to FIG. 1B, when disconnecting in a communication state, the mobile station sends a control message on the reverse dedicated control channel to the disconnect request, after which, in step 153, the base station issues a control message on the direct dedicated control channel for disconnection.

 1A and 1B, there are the following differences between the message used in the call control procedure for serving packet data transmission and the message that complies with the IS-95 standard. In the initialization message (see FIG. 1A, step 115), the packet data mode is added to the service capabilities; in the channel assignment message (see FIG. 1A, step 117), the destination information of the packet data exchange control channel is added to the assignment mode and used as the destination indicator for the dedicated control channel, and information regarding the dedicated control channel (channel identifier and parameter channel), is included in the attached field. In addition, in the disconnect command message (see FIG. 1B, step 153), information regarding the dedicated control channel is included in the attached field. Since the dedicated control channel has not yet been established in the communication procedure, messages regarding the connection are transmitted through the IS-95 channels (i.e., through the clock, paging and access channels). In a state where dedicated control channels for the forward and reverse links are established using messages regarding the connection, call control messages (e.g., disconnect message) are transmitted on the dedicated control channel.

 The dedicated control channel of the present invention is believed to have the following characteristics. Namely, the data transfer rate is 9.6 kbit / s, the frame length is 5 ms or 20 ms, the CRC of the frame consists of 16 bits (for a frame 5 ms long) or 12 bits (for a frame 20 ms long). In addition, in user mode, but not in general mode, several dedicated control channels are required. Dedicated control channels operate only in competing transmission mode, but not in standby transmission mode. In the following description, a frame length of 5 ms will be referred to as the first frame length, and a frame length of 20 ms will be referred to as the second frame length.

 FIGS. 2A-2B show, respectively, structures of a frame of a first length, a frame of a second length, and a traffic frame of a second length.

 In FIG. 2A shows a frame of a first length of 5 ms, where the number 211 denotes a message of the upper level having a fixed length, and the number 212 denotes a frame of the first length transmitted on the physical layer. The message of a fixed length can be a message VCD (dedicated channel UDS (access control to the data transmission medium)) message VKS (dedicated signaling channel), etc. Fig.2B shows a frame of the second length of 20 ms, where the number 221 denotes a message of the upper level having a variable length, and number 222 denotes a frame of the second length transmitted at the physical level. The variable length message may be a video conferencing message. FIG. 2B shows a traffic frame having a second length of 20 ms, where the number 231 denotes a higher layer traffic structure and the number 232 denotes a second length traffic frame transmitted at the physical layer. Traffic can be traffic CGT (dedicated traffic channel). The dedicated traffic channel is intended for the delivery of control messages regarding packet data service (for example, packet traffic channel assignment messages, level 3 control messages, etc.), for the delivery of the IS-95 control message through encapsulation, for the delivery of a short user packet, and for transmitting a power control bit (BOOM) over a forward link.

 To increase the throughput of a CDMA mobile communication system, the frame length of the dedicated control channel should be variable. In particular, to increase throughput, the frame length obtained by dividing the reference frame length by an integer should be used. For example, when the reference frame length is 20 ms, it is preferable to design a system capable of using frames of 5 ms or 10 ms length. According to this embodiment, the use of a frame of 5 ms length is assumed. Thus, it is possible to increase the throughput and reduce the delay of the traffic in comparison with the case of using a frame of 20 ms shown in FIG.

 In FIG. 3A shows transmission time for a second frame length (i.e., a frame length of 20 ms), and FIG. 3B shows transmission time for a first frame length (i.e., a frame length of 5 ms). The time required to send a request message on a dedicated control channel and take appropriate action after receiving a confirmation, according to FIG. 3A is 80 ms when using a frame 20 ms long and according to FIG. 3B is 20 ms, i.e., a fourth of 80 ms when using a 5 ms frame. Of course, this shows the case when the corresponding messages are so short that they can be loaded into a frame of 5 ms length, i.e. when using a 5-millisecond frame you can get the maximum gain. In this case, the reason for the increase in throughput is the efficient transmission of the signal, which increases the time during which the actual user data can be transmitted.

 According to this embodiment, among all states for performing procedures for serving packet data transmission, a dedicated control channel is used in a control blocking state and in an active state. Table 2 shows the relationship between logical channels and physical channels for the forward and reverse links.

 According to table 2, a dedicated UDS channel (VCD) is a forward or reverse channel necessary for transmitting a UDS message and is a point-to-point communication channel assigned in a control blocking state and in an active state for packet service. A dedicated signaling channel (VKS) is a direct or reverse channel, necessary for transmitting a level 3 signaling message, and is a point-to-point communication channel assigned in the control blocking state and in the active state for packet service. A dedicated traffic channel (CGT) is a direct or reverse channel necessary for the transmission of user data, and is a point-to-point communication channel assigned in the active state for packet service.

 The control blocking state mentioned in Table 2 is a state in which, although a dedicated UDS channel (VCD) and a dedicated signaling channel (VKS) are assigned on the forward and reverse links, the exchange of PLR frames (radio link protocol) packets of user data does not occur because a dedicated traffic channel (CGT) is not installed. In addition, the active state is a state in which the VKD, VKS and VKT channels are assigned on the forward and reverse communication lines, which allows the exchange of RLP frames carrying user data packets.

 Therefore, FIGS. 2A-B show a mapping of frames or message data of a logical channel into frames of a physical channel. In this case, the numbers 211, 221 and 231 are the message frames of the logical channel, and the numbers 212, 222 and 232 are the message frames of the physical channel.

 Now we turn to the description of the structures of the frame of the first length and the frame of the second length for the dedicated control channel and operations with them. The frame length of the dedicated control channel dynamically changes in accordance with the nature of the message. At the receiver, the frame length is determined every 5 ms.

 In a packet channel communication control mode for transmitting a fixed message length of 5 ms shown in FIG. 2A, a request / assignment for the forward and reverse packet traffic channels is performed using a 5-millisecond request / confirmation message. The assignment of the forward packet traffic channel that begins at the base station is independent of the destination of the reverse packet traffic channel that begins at the mobile station. Communication control messages include a packet traffic channel request message, a packet traffic channel assignment message, and a packet traffic channel confirmation message. Among all the logical channels, the VCD channel is used to transmit these messages. Table 3 shows the fields of the channel allocation message for the reverse packet traffic channel as applied to a frame of the first length equal to 5 ms.

The relevant fields shown in table 3 mean:
"Header information" - identifier, direction and type (ie request and confirmation) of the message;
"Sequence" - message sequence;
"Start time" - the time the channel started to use;
"Assigned speed" - data transfer rate on the assigned channel;
"Assigned Duration" - the duration of the use of the assigned channel.

 A message of a fixed length of 24 bits, presented in table 3, is transmitted on a dedicated control channel in the form of a 5-millisecond frame shown in figa.

 FIG. 4 is a flowchart illustrating a procedure for assigning and releasing a packet traffic channel through a dedicated control channel when the system transitions from the control lock state to the active state, and then transitions from the active state to the control lock state.

According to FIG. 4, it is assumed that, at step 411, the base station and the mobile station maintain a control blocking state in which a dedicated control channel is in communication. In this state, the mobile station generates a control message to request the destination of the reverse packet traffic channel through the UDS (VCD) channel and sends it on the physical channel in step 413. Then, the base station generates a control message to assign the reverse packet traffic channel through the dedicated UDS (VCD) channel and sends the generated control message over the physical channel at step 415. After that, at step 417, the base station and the mobile station enter an active state when, for transmission of packet The data is assigned a packet traffic channel. In this active state, the mobile station in step 419 initializes the timer T _asset to control the time during which the transmission of packet data is suspended. In this case, if the transfer of packet data has not yet been completed by the time the _asset T timer expires, the active state is maintained, followed by the repeating of the T _asset timer timer initialization step 419.

However, if the packet data transfer is already completed by the time the _asset T timer expires, then at step 421 the mobile station receives information about this and generates a control message to request the release of the packet traffic channel through the dedicated UDS (VCD) channel and sends the generated control message on the physical channel in step 423. In response to the control message, the base station generates a control response message to release the reverse packet traffic channel through the dedicated channel l UDS (VCD) and sends the generated control message on the physical channel at step 425. Thus, at step 427, the base station and the mobile station, having released the reverse traffic channel and entering the control blocking state, are ready to transition to the next state.

According to FIG. 4, during the procedure for requesting and assigning the reverse channel of packet traffic, the mobile station generates a request message for the reverse channel of packet traffic, including information on the requested data rate on the channel, and sends it to the base station. After that, the base station analyzes the received message to determine whether it can support the requested parameter, and sends to the mobile station, in response to the request message, the reverse packet channel assignment control message mentioned in Table 3 according to the definition made. If necessary, additional coordination of the above request and response procedures may be repeated. In addition, if during the time allotted for the exchange of packet data, no packet data is transmitted, then after the time specified by the _asset timer T expires, the process of releasing the packet traffic channel is carried out.

 In transmission mode, for a variable-length frame, a variable-length message complying with the IS-95 standard is partially loaded into 20 millisecond frames of a dedicated control channel as shown in FIG. 2B. Specifically, the transmission modes may include a frame transmission mode without detecting and correcting errors carried out by the PTDT / OTRPTTV (acknowledgment / negative acknowledgment), a mode in which the PTTT / OTRPTTV is performed when a variable-length message is received in its entirety and the entire message is retransmitted variable length, and the mode in which the PDTV / OTRPTV is carried out for the respective frames.

 In the user data transmission mode, the RLP frames carrying the user traffic are partially loaded into the 20 millisecond frames of the dedicated control channel according to Fig. 2B. The user data transmission mode can be used when it is not advantageous to establish a packet traffic channel for data transmission because of the small amount of data to be transmitted.

 We now turn to the description of a physical device for transmitting frames of a dedicated control channel in a CDMA mobile communication system that uses the above dedicated control channel.

 First of all, we will describe a frame transmission device for a direct dedicated control channel with reference to FIGS. 5A and 5B. According to the figures, the buffer 511 control message is intended for temporary storage of a control message transmitted over a dedicated control channel. The size of the buffer 511 of the control message must be such that it can store one or more frames of the second length equal to 20 ms. In addition, the control message buffer 511 is designed to coordinate the transmission of the control message from the upper level processor to the modem controller 513. In this case, after storing the control message in the control message buffer 511, the top-level processor sets a flag in the header information to distinguish between 5 ms and 20 ms frames according to the type of message, and the modem controller 513 eliminates this flag after reading the control message to prevent repeated write and reread.

 After reading the control message stored in the control message buffer 511, the modem controller 513 analyzes the control message header to detect the type of message, outputs a message (or payload) to be transmitted on the dedicated control channel in accordance with the detected message type, and outputs a control signal, corresponding to the detected message type. In this case, the control signal generated by the modem controller 513 is a frame selection signal for selecting between frames of a first and second length. Regarding the type of message, the control message may be the first control message transmitted through frames of 5 ms, which is shown in figa, or the second control message transmitted by frames of 20 ms, which is shown in figb, and the amount of control data output from the modem controller 513 depends on the result of the analysis. Thus, in the case of transmitting a control message by means of 5 ms frames, the modem controller 513 outputs 24-bit data, the structure of which is shown in Table 3; in the case of transmitting a control message by means of 20 ms frames, the modem controller 513 outputs 172-bit data. In addition, the modem controller 513 determines the absence / presence of a control message in order to control the output of the dedicated control channel. Thus, in the presence of a control message to be transmitted, the modem controller 513 generates a first gain control signal and, in the absence of a control signal to be transmitted, generates a second gain control signal to suppress (block) the signal transmitted through the dedicated control channel. In this case, the gain control signals are output control signals intended to control the output of the transmitted signal to the dedicated control channel. Although the description of the present invention is based on an embodiment in which a gain controller is installed prior to the stretcher, it is also acceptable to install a gain controller after the stretcher.

 The CRC generator (cyclic redundancy code) 515 adds CRC bits to the control message output from the modem controller 513, which makes it possible to determine the quality of the frame at the receiver (i.e., to determine whether the frame contains an error). Specifically, in the case of a 5-millisecond frame, the CRC generator 515, on the control signal of the modem controller 513, generates a 16-bit CRC for outputting a 40-bit control message; in the case of a 20 millisecond frame, the CRC generator 515 generates a 12-bit CRC to output an 184-bit control message.

 The tail bit generator 517 generates tail bits necessary to complete the error correction code. The tail bit generator 517 analyzes the output of the CRC generator 515 to generate tail bits in accordance with the analysis and adds the generated tail bits to the output of the CRC generator 515. Specifically, the tail bit generator 517 generates 8 tail bits and adds them to the output of the CRC generator 515. Therefore, in the case of transmitting a control message by means of 5 ms frames, the control message output from the tail bit generator 517 consists of 48 bits, which is shown in FIG. 2A at 212. In the case of transmitting a control message by means of 20 ms frames, the control message output from the tail bit generator 517, consists of 192 bits, as shown in FIG. 2B at 222.

Encoder 519 encodes the output of the tail bit generator 517. The encoder 519 used in this embodiment is a conventional encoder or turbo encoder using a 1/3 coding coefficient. The interleaver 521 interleaves the coded
control data output from encoder 519. In other words, interleaver 521 changes the location of the bits in the frame unit of the message to increase resistance to the burst of errors.

 A CRC generator 515, a tail bit generator 517, an encoder 519, and an interleaver 521 form a control message generating unit 550 for generating a control message and transmitting the generated control message over a physical channel. FIG. 5A shows an example of a structure in which a control message generating unit 550 processes control messages transmitted by both 5 millisecond and 20 millisecond frames. However, the transmitting device may include as many control message generating units as the size of the control message frame is processed on the dedicated control channel, and to generate a control message, use the control message generating unit corresponding to the length of the frame to be transmitted, as selected by the modem controller 513. In this case, the corresponding control message generating unit should include a CRC generator, a tail bit generator, an encoder and an interleaver corresponding to the frame length of the corresponding control message.

 The signal mapper 523 converts the transmitted signal by converting the logical “1” of the transmission signal to “-1” and the logical “0” of the transmission signal to “+1”. The gain controller 525, the gain multiplier, generates or blocks the path for the transmitted control message of the dedicated control channel in accordance with the gain control signal UE coming from the modem controller 513. Thus, the gain controller 525 implements the PP (discontinuous transmission) mode in which, in the presence of a control message to be transmitted, the path on the dedicated control channel is formed in accordance with the gain control signal, and in the absence of a control message to be transmitted, the path The dedicated control channel is blocked.

 A serial-to-parallel converter (D / A) 527 multiplexes the characters of the control message output from the gain controller 525 in order to distribute them among the stretchers of the corresponding RF communication channels. According to this embodiment, for example, 3 RF communication channels are used. In this case, each of the 3 RF communication channels has two phase branches (i.e., branches I and Q). Since the control message transmitted by means of a frame of 5 ms length consists of 144 characters, the number of symbols displayed through branches I and Q of each of the RF communication channels is 24. Further, since the control message transmitted by means of frames of 20 ms consists of 576 characters, the number of characters output through the branches I and Q of each of the RF communication channels is 96. Sometimes, a dedicated control channel may use a single RF communication channel. In this case, the P / N converter 527 simply performs the distribution function of the I and Q branches of a single RF communication channel. "Composter" 529 BOOM (power control bit) "composts" the control bit to be transmitted to the mobile station on a forward link. In this case, the control bit may be a power control bit (BOOM) designed to control the reverse link power of the mobile station.

 On figb depicts a stretcher, designed to stretch the characters displayed from the composter 529 BOOM. According to this embodiment, the number of stretchers equal to the number of RF communication channels is provided. For convenience of explanation, FIG. 5B shows the structure of a stretcher corresponding to a separate RF communication channel. 5B, an orthogonal code generator 535 generates an orthogonal code used for a dedicated control channel. In this case, the orthogonal code may be a Walsh code or a quasi-orthogonal code. Multipliers 531 and 533 multiply the orthogonal code generated by the orthogonal code generator 535 by the corresponding signals of branches I and Q, respectively, in order to provide stretched control signals for a dedicated forward link control channel. Although the description of the invention is based on an implementation option, according to which the orthogonal code is stretched using the modulation of DVM (binary phase shift keying), the orthogonal code can be stretched using the CPM modulation (quadrature phase shift keying).

When performing the stretching of the signals of the branches I and Q, the PS codes (pseudo-random noise sequence) are received on the modulator 537: PN _i and PN _q , issued by an unassigned PN sequence generator. As a modulator 537, a complex multiplier can be used.

 According to FIG. 5A and 5B, using a quasi-orthogonal code, the number of code channels can be increased due to the FEC rate. In addition, on a forward link, power fluctuation due to composting of the power control bit can be prevented by spacing a code bit level frame.

 5A, the frame length (5 ms or 20 ms) of the control message to be transmitted is determined by the modem controller 513. This means that the modem controller 513 determines the frame length by checking the header information for whether the control message stored in the control message buffer 511 is a 24-bit fixed-length control message or a variable-length control message. If the header information represents a 24-bit control message of a fixed length, the modem controller 513 determines that the control message has a frame length of 5 ms. If the header information represents a variable length control message, the modem controller 513 determines that the control message has a frame length of 20 ms. The modem controller 513 generates a control signal for the control message generating unit 550 in accordance with the determined frame length determination. In this case, the numbers in the subunits 515, 517, 519 and 521 of the control message generating unit 550 express the number of bits corresponding to the frame length; for a frame with a length of 5 ms, the upper parameters are used, and for a frame with a length of 20 ms, the lower parameters are used.

 In addition, the modem controller 513 controls the dedicated control channel in PP mode. Thus, according to an advantageous embodiment, the signaling message and the message regarding the MAC used for data transmission services are transmitted / received on a dedicated control channel, which contributes to the efficient use of channel capacity. The structure of the IS-95 system provides multiplexing of voice traffic and signaling traffic, as a result of which voice and signal channels must be normally open for data transmission services. However, since the dedicated control channel corresponding to the invention operates in the PP mode, there is no need to keep the channel for control signals normally open. In the absence of signaling information to be transmitted, it is possible to suppress the transmit power by the PP gain controller and, thus, effectively use the bandwidth of the radio channel.

 As for the discontinuous transmission (PP) mode, when it turns out that the control message buffer 511 does not contain the control message to be transmitted, the modem controller 513 generates a second gain control signal so that the gain controller 525 keeps the output of the dedicated control channel equal to " 0 ". Thus, in the presence of a control message to be transmitted, the modem controller 513 generates a first gain control signal (CI = predetermined gain), and if there is no control message to be transmitted, it generates a second gain control signal (CI = 0). However, in this case, there may be a problem with composting BOOM. In addition, although the description of the invention is based on an embodiment according to which the PP mode for the dedicated control channel is performed using the gain controller 525, in the absence of a control signal to be transmitted on the dedicated control channel, the signal path can also be blocked using the switch.

 FIG. 5A and 5B illustrate the structure of a dedicated control channel transmission apparatus for a forward link (from a base station to a mobile station). The transmitting device of the dedicated control channel for the forward link should perform the composting operation of the BOOM in order to control the transmit power of the mobile station. However, the transmitting device of the dedicated control channel for the reverse link (from the mobile station to the base station) is not required to perform the composting operation of the PCB. Accordingly, the transmitter of the dedicated control channel for the reverse link may have the structure shown in Fig.6.

 According to FIG. 6, the dedicated control channel transmission device for the reverse link has the same structure as the dedicated control channel transmission device for the forward link, with the exception of the P / N converter, the stretcher structure, and the coding coefficient of the convolutional encoder. According to this embodiment, the coding coefficient of the forward link encoder is 1/3, and the coding coefficient of the reverse link encoder is 1/4.

 When transmitting a control signal using the reverse dedicated control channel, the transmitting device of the dedicated control channel for the reverse link also determines the frame length in accordance with the size of the control message and transmits the control message through frames whose length it has determined. In addition, the transmitter of the dedicated control channel for the reverse link checks the presence / absence of a control message to be transmitted on the reverse dedicated control channel to suppress the output of the reverse dedicated control channel in the absence of a control signal to be transmitted so that the output signal path for the reverse channel control was formed only in the presence of a real control message to be transmitted.

 According to FIG. 6, a stretcher 631 stretches a control signal output through a dedicated control channel using an orthogonal code and a PN sequence.

 A device for receiving control signals transmitted on the forward or reverse dedicated control channel must determine the frame length of the control message in order to process the control message. The receiver of the dedicated control channel for the forward or reverse link may have the structure shown in figa and 7B.

 In FIG. 7A and 7B depict receivers of a dedicated control channel for the forward and reverse links in accordance with the present invention.

 According to FIG. 7A, a compressor 711 compresses a received signal using a PN sequence and an orthogonal code to receive a dedicated control channel signal. Diversity combiner 713 combines multiple path received signals from a compressor. The soft decision generator 715 quantizes the received signal into a digital value of several levels to decode the received signal. The deinterleaver 717 deinterleaves the coded symbols interleaved in the transmission process to restore the original character arrangement. In this case, the deinterleaver 717 must deinterleave both the 5-millisecond frame and the 20-millisecond frame so that their deinterleaving is performed in the same manner as on the interleaver of the transmitting device of the dedicated control channel. Therefore, as shown in FIG. 7B, two inverted interleavers can also be used. 7B, the first deinterleaved interleaver 717 de-interleaves the interleaved frame data in the same manner as the interleaver of a 5-millisecond frame of a transmitting device of a dedicated control channel. Similarly, the second deinterleaver 718 performs deinterleaving of the interleaved frame data in the same manner as the interleaver of a 20 millisecond frame of a transmitter of a dedicated control channel.

 A timer 719 generates a decoding control signal for data received on the dedicated control channel with a fixed amount of time. In this case, the timer 719 is a 5 millisecond timer. The first decoder 721 is turned on by a control signal issued by a timer 719, and decodes the deinterleaved data coming from the first deinterleaver 717. The first decoder 721 decodes the first control message transmitted by a 5 ms frame. The second decoder 723 is turned on by the control signal issued by the timer 719, and decodes the data subjected to deinterleaving, coming from the second deinterleaver 718. The second decoder 723 decodes the second control message transmitted by frames of 20 ms. The first CRC detector 725 receives the output of the first decoder 721 and checks the CRC of the 5 millisecond frame. The second CRC detector 727 receives the output of the second decoder 723 and checks the CRC of the 20 millisecond frame. In this case, the resulting signal of the first and second CEC detectors 725 and 727 is a logic signal that takes the value true (1) or false (0).

 Block 729 decision on the frame analyzes the resulting signals from the first and second detectors 725 and 727 of the CRC, with the aim of deciding on the frame length of the control message received on a dedicated control channel. Block 729 decision frame generates a selection signal select 1 to select the first decoder 721, when the first CRC detector 725 outputs a signal with a value of true, generates a selection signal select 2 to select a second decoder 723, when a second CRC detector 727 outputs a signal with a value of true "and generates a DISABLE signal to block the output signals of the first and second decoders 721 and 723 when the first and second CRC detectors 725 and 727 both generate a false signal.

 The selector 731 selects the decoded data output from the first and second decoders 721 and 723, in accordance with the output signals of the block 729 decision on the frame. Thus, the selector 731 selects the output signal of the first decoder 721 when the received frame is a 5 millisecond frame, selects the output signal of the second decoder 723 when the received frame is a 20 millisecond frame, and blocks the output signals of both decoders - the first, 721, and the second , 723 - for a period of time during which the control ratio is not received.

 The modem controller 733 stores the received control message in the form of decoded data output from the selector 731 in the control message buffer 735. Then, the upper level processor reads and processes the control message stored in the control message buffer 735.

 Now we turn to the description of the operation of the receiving device of the dedicated control channel with reference to figa and 7B. Compressor 711 receives a control signal over a dedicated control channel and compresses the received control signal using a PN sequence. The control signals received on the dedicated control channel are restored to the original shaft of the control message of the transmission process.

 After that, both at the mobile station and at the base station, the first decoder 721 decodes 5 millisecond frames, and the second decoder 723 decodes 20 millisecond frames to process the control message. The first and second CRC detectors 725 and 727 then verify the decoded data output, respectively, from the first and second decoders 721 and 723, and output the resulting values to the frame decision block 729. In accordance with the results of the CEC check, the frame decision block 729 makes a decision regarding the frame length of the received control message, as well as whether the frame is being transmitted.

 We denote the CEC test result of the 5-millisecond frame of CEC 5, and the CEC test result for the 20-millisecond frame, denote CEC 20. Table 4 shows the selection signals generated by the frame decision block 729.

 According to Table 4, when neither CEC5 nor CEC20 is detected (that is, false), no frame data is received, which corresponds to the period of time when the transmitting device does not transmit a control message in intermittent transmission mode. However, the detection of both CRIC5 and CRIC20 (i.e. both have a value of "true") indicates a frame error.

 During transmission, the radio signal may include impulse noise due to other electronic equipment and the power line. In this case, the receiver of the mobile communication system may mistakenly perceive the noise components as frame data. As a result, it is likely that the CEC detector will produce an output signal with a value of true, although noise has been received instead of the effective frame.

 In FIG. 8 depicts a dedicated control channel receiver in accordance with another embodiment of the present invention, which includes a frame detector for detecting an effective (or usable) data frame when a transmitter of a mobile communication system intermittently transmits data of a single-length frame. FIG. 10 is a flowchart illustrating a method for detecting a suitable frame in a frame detector 740 included in a receiver of FIG. 8.

 For convenience of explanation, we assume that the size of the frame data transmitted by the transmitting device is 5 ms, and the number of decoded symbols output from the decoder is 144.

 According to FIG. 10, the value of the symbol energy obtained by squaring the output signal of the combiner 713 of the diversity signals shown in Fig. 8 is stored in the register b, the energy value output from the register b is accumulated in the register S, and the accumulated number of incoming symbols is stored in the register n. Thus, in the register b, the energy value of the incoming symbols is stored, and in the register S, the energy values of the symbols are accumulated in accordance with the number of characters stored in the register n.

 According to FIG. 8 and 10, the received signal is compressed by a squeezer 711 and, by the diversity combiner 713, is combined with signals received over multiple paths. Then, the frame detector 740 receives the combined signal output from the diversity combiner 713 and detects a suitable frame using the procedure shown in FIG. 10, and outputs a signal with a value of true (1) or a signal with a value of false (0) in accordance with the results of detecting a frame.

 Then according to FIG. 10, the frame detector 740 in step 1011 initializes register S and register n (S = 0 and n = 0). After initialization, if the diversity combiner 713 generates an output signal, the frame detector 740 in step 1013 calculates a symbol energy value, squaring the output of the diversity combiner 713, and stores the value in register b. In step 1015, the frame detector 740 updates the register S by adding the value of register b to the previous value of the register S and updates the number of incoming characters, increasing the value of register n by one. After increasing the value of the register n, the frame detector 740 in step 1017 determines whether the value of the register n has reached the number 144. Thus, since the data of the 5-millisecond frame consists of 144 characters, it becomes clear in step 1017 whether the data of the 5-millisecond frame is completely received. If it turns out at step 1017 that the value of register n is less than 144, the frame detector 740 returns to step 1013 to repeat the procedure for detecting the energy value of the incoming characters and accumulating the value of register S, since the reception of the 5-millisecond frame data has not yet been completed.

 When, finally, the value of register n reaches 144, the frame detector 740 concludes that the data of the 5-millisecond frame has been completely received and compares in step 1019 the value accumulated in the register S with the threshold value. In this case, the threshold value is set equal to the minimum energy value of a 5 millisecond suitable frame, and it can be used as a reference value for deciding whether to receive a 5 millisecond frame. If, as a result of the comparison, it turns out that the value of the register S is greater than the threshold value, the frame detector 740 proceeds to step 1021 to output a signal with the value "true" to the block decision block 730; if it turns out that the value of the register S is less than the threshold value, then the frame detector 740 proceeds to step 1023 to output a signal with the value "false" to the block decision block 730. When a signal with a false value is received at block 730 for making a decision on the frame, the transmitting device performs a discontinuous transmission mode, suppressing the transmission of a control message.

 When, in accordance with the procedure shown in FIG. 10, the frame detector 740 generates a signal with a value of “true” or a signal with a value of “false”, the frame decision block 730, through the procedure shown in FIG. 12, generates a control signal for frame length selection. FIG. 12 is a flowchart illustrating a decision method regarding a frame length and its availability by a decision block 730 depicted in FIG.

 According to FIG. 12, the frame decision block 730, in step 1211, determines whether the frame detector 740 provides a signal having a value of true. If the received frame detection signal is true, the frame decision block 730, at step 1213, checks the value of the signal generated by the CRC detector 725. If it turns out at step 1213 that the signal received from the CRC detector 725 has a value of “true”, the frame decision block 730 at step 1215 generates an ON signal to the selector 731, after which the procedure ends. However, if it is determined at step 1211 that the received frame detection signal is not true, the frame decision block 730 generates a DISABLED signal to the selector 731, after which the procedure ends. In addition, if it is determined at step 1213 that the output of the CRC detector 725 is not true, the frame decision block 730 generates a DISABLED signal to the selector 731, after which the procedure ends. In this case, the frame decision block 730 may decide whether or not frame data is being received based solely on the output of the frame detector 740.

 Then, the selector 731 selects the output signal of the decoder 721 to supply it to the modem controller 733 or controls (in the sense of blocking) the output signal of the decoder 721 in accordance with the ON or OFF signal, which is provided by the frame decision block 730.

 In the description of FIGS. 8, 10 and 12, it was assumed that the received frame has a length of 5 ms. However, the above method of detecting a frame and deciding on a frame can equally well be applied to frames having a different length. Thus, in the case of a 20 millisecond frame, the deinterleaver 717, the decoder 721, and the CRC detector 725 shown in FIG. 8 are modified to receive and process the 20 millisecond frame, and the frame detector 740 detects the frame in accordance with the procedure shown in FIG. .eleven. Thus, in the case of a 20 millisecond frame, when the number of characters output from the encoder of the transmitting device is 576, the frame detector 740 accumulates the energy value of characters received over a duration of 576 characters and compares the accumulated value with a threshold value to determine if it is detected frame or not. In this case, the threshold value for a 20 millisecond frame can be set equal to the minimum energy value of a 20 millisecond suitable frame and used as a reference value to determine whether data is received in a 20 millisecond frame.

 Table 5 shows the results of the decision made by the decision block 730 on the frame based on the output signals of the frame detector 740 and the CRC detector 725, according to the procedure shown in Fig. 12.

 According to table 5, when both outputs of the frame detector 740 and the CRC detector 725 are not true, the frame decision unit 730 concludes that the transmitting device is not transmitting a message frame (“No frames”) or that the frame contains an error ( "Error frame"). According to this embodiment, when both output signals of the frame detector 740 and the CRC detector 725 are false, the frame decision unit 730 concludes that the transmitting device is not transmitting a message frame; when one of the output signals of either the frame detector 740 or the CRC detector 725 is a false signal, the frame decision unit 730 concludes that the corresponding message frame is an error frame.

 FIG. 9 shows a receiver device according to another embodiment of the present invention, which includes two frame detectors for detecting frames having two different lengths. FIG. 11 is a flowchart illustrating a suitable frame detection method implemented in the second frame detector 741 of FIG. 9.

 In the following description, it is assumed that the first and second frames have a length of 5 ms and 20 ms, respectively. Further, the first frame, 5 ms long, and the second frame, 20 ms long, consist of 144 characters and 576 characters, respectively.

 According to FIG. 9, the receiving device includes a first frame detector 743 and a second frame detector 741 for receiving frames having different lengths. The remaining structures remain the same as in FIG. According to FIG. 9, the first frame detector 743 is a 5 millisecond frame detector, and the second frame detector 741 is a 20 millisecond frame detector. The first frame detector 743 performs the same operations shown in FIG. 10 as the frame detector 740 shown in FIG.

 Similarly, the second frame detector 741 receives the output of the diversity combiner 713, detects a suitable second frame in accordance with the procedure of FIG. 11, and outputs a signal capable of accepting true or false depending on the detection results, steps 1111 1115 indicated in FIG. 11 are identical to steps 1011-1015 indicated in FIG. 10. However, the second frame detector 741 repeats steps 1113 and 1115 until at step 1117 it is detected that the value of register n has reached 576. After that, the second detector 741 at step 1119 compares the accumulated value of register S with a threshold value in order to determine whether the accumulated value of register S is a threshold value. If, as a result of the comparison, it is found that the value of the register S is greater than the threshold value, then the second frame detector 741 at step 1121 outputs to the block 750 decision on the frame a signal having the value "true"; if the value of the register S is less than the threshold value, the second frame detector 741 proceeds to step 1123 and provides a signal with a false value to the block decision block 750.

 Having received a signal with the value "true" or "false" from the first 743 and second 741 frame detectors, the frame decision block 750 carries out the procedure shown in Fig. 13. FIG. 13 is a flowchart illustrating a method for determining a frame length performed by the frame decision unit 750 of FIG. 9.

 13, at block 1311, the frame decision block 750 checks whether the signal from the first 743 and second 741 frame detectors has a value of “true”. In the case of a frame detection signal having a value of “true”, the frame decision block 750 determines in step 1313 whether the frame detection signals in the value “true” were received from both the first 743 and second 741 frame detectors. If it turns out that both the first 743 and the second 741 frame detectors received frame detection signals in the true value, the frame decision unit 750 checks in step 1315 whether the first CRC detector 725 outputs a signal having the true value. When a signal having a true value is received from the first CRC detector 725, the frame decision block 750 proceeds to step 1317 to determine whether the second CRC detector 727 outputs a signal having a true value. When “true” signals are received from both the first 725 and second 727 CEC detectors, the frame decision block 750 generates at step 1319 a select signal 2 for supply to selector 731 so that selector 731 selects the output signal of the second decoder 723 and filed the selected frame to the modem controller 733.

 However, if it is determined at step 1315 that the signal from the first CRC detector 725 does not have a value of "true", then the frame decision unit 750 checks at step 1321 whether the signal from the second CRC detector 727 has a value of " true". If as a result of the check it turns out that the incoming signal has the value "true", then the frame decision block 750 proceeds to step 1319 and generates a select signal 2 for supply to the selector 731. Based on the select signal select 2, the selector 731 selects the output signal of the second decoder 723 and outputs the selected signal to the modem controller 733. However, if it is determined at step 1321 that the output of the second CEC detector 727 is false, the selector 731 issues a DISABLED signal and ends the procedure. In this case, the selector 731 does not select any of the output signals of the first and second decoders 721 and 723. Thus, no data is transmitted to the modem controller 733.

 In addition, if it turns out at step 1313 that only one of the frame detectors, either the first 743 or the second 741, gives a signal having the value “true”, then the frame decision block 750 determines at steps 1323 and 1329 whether this a signal from a first frame detector 743 or from a second frame detector 741. If it turns out that the signal with the value “true” has come from the first detector 743 of the frame, the block 750 decision on the frame checks at step 1325 whether the first detector 725 CEC signal with the value “true”. If the output of the first CEC detector 725 is true, the frame decision block 750 generates at step 1327 a select signal 1 for supply to the selector 731. If the output of the first CEC detector 725 is false, the decision block 750 frame generates a signal OFF. As a result, the selector 731 selects the output signal of the first decoder 721 for supplying the modem to the controller 733 based on the select signal, and blocks the output signals of the first and second decoders 721 and 733 on the OFF signal.

 In addition, the frame decision block 750 determines, at step 1329, whether a signal with a value of true is being received from the second frame detector 741. If so, then the frame decision block 750 determines in step 1311 whether the second CRC detector 727 provides a true value. If the second CEC detector 727 outputs a signal having a value of true, the frame decision block 750 proceeds to step 1319 and generates a select signal 2 for supply to the selector 731. If the second CEC detector 727 produces a signal with a value of false, block 750 decision on the frame generates a DISABLE signal to selector 731, as a result, selector 731 selects the output signal of the second decoder 723 to be fed to the modem controller 733, and blocks the output signals of the first and second decoders 721 and 723 by the OFF signal.

 Table 6 shows the output signals of the frame detectors 741 and 743, the CRC detectors 725 and 727, and the frame decision block 750 in accordance with the procedure shown in FIG. 13.

 The “False frame” mentioned in Table 6 means that the transmitting device does not transmit a message frame (ie, “No frames”) or that the frame received an error during transmission (ie, “Error frame”). In the case of a “False frame”, the frame decision block 750 checks the output signals of the frame detectors 741 and 743 and the CEC detectors 725 and 727 to determine whether the false frame corresponds to the “No frames” state or the “Error frame” state. According to this embodiment, the frame decision block 750 provides the decision results in accordance with the output signals of the frame detectors 741 and 743 and the CRC detectors 725 and 727 according to table 7.

 The outputs of the frame decision block 750 are supplied to the modem controller 733, according to FIG.

 According to FIG. 14, when the frame decision block 750 generates a select 1 or select 2 signal, the selector 731 selects a decoded message for the frame corresponding to the select signal and outputs the selected message to the modem controller 733. Then, the modem controller 733 issues a received message to the upper level processor. However, when the frame decision block 750 generates a DISABLED signal, the selector 731 blocks the output path of the decoded message. In this case, the modem controller 733 checks the frame decision signal issued by the frame decision block 750. When the frame decision signal represents the No Frame state, the modem controller 733 does not output the decision result to the upper layer, determining that no message has been transmitted from the transmitter. If the decision signal on the frame represents the "Error frame" state, the modem controller 733 outputs the decision result to the upper level processor, determining that the transmitting device transmitted the message, but an error was introduced into the message during transmission. Thus, the top-level processor is given the opportunity to take appropriate action in relation to the erroneous frame.

 FIG. 15 illustrates a simulation result of processing control messages having a variable frame length on a dedicated control channel in accordance with the present invention. On Fig shows the result of comparing the bandwidth when using on a dedicated control channel 5-millisecond frame and 20-millisecond frame. In this case, the direct channel of packet traffic is characterized by a data transfer rate of 307.2 kbit / s, a fixed-length frame of 20 ms, and a QCO (frame error rate) of 1%.

According to the above, the CDMA mobile communication system according to the present invention has the following advantages:
(1) A control message transmitted over a dedicated control channel has a different length in accordance with the size of the control message, which makes it possible to increase throughput and reduce traffic delay by using a dedicated control channel.

 (2) A dedicated control channel is used in intermittent control mode in accordance with the presence / absence of a control message to be transmitted.

 (3) The system provides reliable transmission through faster detection and correction of errors compared to the IS-95 system. In addition, the system efficiently uses the resources of the radio channel due to the use of the optimal channel environment and can provide improved voice service through a dedicated control channel, which makes it possible to effectively maintain the IS-95 message.

 (4) In a CDMA mobile communication system, it is possible to reduce the probability of receiving erroneous frames by using the result of measuring the frame energy and the result of detecting an error.

 Although the description of the invention is based on specific variants of its implementation, it will be apparent to those skilled in the art that it allows various changes in form and detail, not intended to depart from the spirit and scope of the invention as set forth in the claims below.

Claims (27)

 1. A device for transmitting data on a dedicated control channel for a code division multiple access (CDMA) system having at least two different frame lengths, comprising a modem controller for detecting a type of message, outputting a message to be transmitted on a dedicated control channel, and a control signal in the form of a message frame selection signal corresponding to the detected message type, at least one message generator for generating a message data frame to be transferred cottage, in accordance with the frame selection signal, and an expander designed to expand the frame of the data message for a dedicated control channel.  2. The device according to p. 1, characterized in that the message generator comprises a cyclic redundant code generator (CRC), designed to generate CRC bits for a message characterized by a frame length determined in accordance with the frame selection signal, and to add to the message CRC bits, tail bit generator for generating tail bits and for adding generated tail bits to the output signal of the CRC generator, an encoder for encoding frame data, to which Lena tail bits, with a given coding coefficient and interleaver, designed to change the location of bits in the personnel unit of the message.  3. The device according to claim 1, characterized in that the message data frame includes a 5 ms frame and a 20 ms frame.  4. The device according to claim 1, characterized in that the message includes a user control message, a signaling message and a message for access control to the data medium of the DCS.  5. The device according to claim 1, characterized in that it contains message generators in an amount equal to the number of lengths of the message frame to be transmitted.  6. The device according to p. 1, characterized in that it contains a gain controller designed to generate or block the path for the control message to be transmitted to the dedicated control channel in accordance with the gain control signal received from the modem controller, wherein the gain controller performs discontinuous transmission (PP) mode, in which, in the presence of a message to be transmitted, path formation on a dedicated control channel is performed in accordance with the gain control signal, in accordance with, and in the absence of a message to be transmitted, the path is blocked.  7. A method of transmitting data in a code division multiple access (CDMA) system having at least two different frame lengths, which consists in determining the type of message, outputting the message to be transmitted on a dedicated control channel, and a control signal as a message frame selection signal corresponding to the detected message type, data of a message frame to be transmitted in accordance with a message frame selection signal is generated, message frame data is expanded on a dedicated control channel.  8. The method according to claim 7, characterized in that the steps of generating the frame data comprise the steps of generating CRC bits for the message to be transmitted and adding CRC bits to the message; generating tail bits and adding tail bits to the message to which the CRC bits are added; encode the frame data, to which the tail bits are added, with a given coding coefficient, and interleave, designed to change the location of the bits in the frame unit of the message.  9. The method of claim 7, wherein the message data frame includes a 5 ms frame and a 20 ms frame.  10. The method according to p. 7, characterized in that the message includes a user message, a signaling message, and a medium access control (MAC) message.  11. The method according to p. 7, characterized in that the controller form or block the path for the control message to be transmitted, the dedicated control channel in accordance with the control signal of the gain coming from the modem controller, and the gain controller performs discontinuous transmission (PP ), in which, in the presence of a message to be transmitted, a path is formed on the dedicated control channel by the signal of the dedicated control channel in accordance with the control signal of the coefficient у power, and in the absence of messages to be transmitted, the path is blocked.  12. The method according to p. 11, characterized in that the transmit gain for the message is zero in the discontinuous transmission mode.  13. A device for receiving control signals transmitted over a dedicated control channel for a CDMA system having at least two different frame lengths, comprising a compressor for compressing the received signal, a first message receiver for reverse deinterleaving and decoding the compressed signal, characterized by the first the frame length, with the possibility of issuing the first message, and to detect the first CRC detection signal corresponding to the decoded signal, the second message receiver, pre assigned to deinterleave and decode the compressed signal, characterized by a second frame length, with the possibility of issuing a second message, and to detect a second CRC detection signal corresponding to the decoded signal, and a controller for selecting between the first and second messages in accordance with the first and second signals detecting CRCs received by the first and second message receivers.  14. The device according to p. 13, characterized in that the controller comprises a frame decision block for analyzing the first and second results of the CEC detection and configured to make a decision on the frame of the received message and issue a decision signal on the frame, and a selector designed to select one of the decoded signals output from the first and second message receivers, in accordance with the frame decision signal.  15. The device according to p. 13, characterized in that the first and second lengths of the message data frame are 5 and 20 ms, respectively.  16. Device for receiving data transmitted over a dedicated control channel for a CDMA system having at least two different frame lengths, comprising a compressor designed to compress the received signal, a frame detector designed to detect the energy of the compressed signal, characterized by the first and second frame lengths, and for issuing the first and second frame detection signals in accordance with the frame detection results; a first message receiver for deinterleaving and decoding a compressed signal having a first frame length to provide a first message; a second message receiver for deinterleaving and decoding the compressed signal having a second frame length to provide a second message, and a controller for selecting between the first and second messages in accordance with the first and second frame detection frame detection signals.  17. The device according to p. 16, characterized in that the controller comprises a frame decision block for analyzing the first and second frame detection signals with the possibility of deciding on the frame length of the received message and issuing a decision signal on the frame length, and a selector designed to select one of the decoded signals output from the first and second message receivers, in accordance with the frame decision signal.  18. The device according to p. 16, characterized in that the first and second lengths of the message data frame are respectively 5 and 20 ms.  19. The device according to p. 16, characterized in that the frame detector comprises first and second frame detectors, the first frame detector having a minimum value of energy of an effective frame of 5 ms length as a reference value and is configured to compare the energy value of the received data frame messages with a minimum energy value of the effective frame length of 5 ms, to generate a first frame detection signal when the energy value of the received data frame of the message is higher than the minimum energy value of the effective a frame length of 5 ms, the second frame detector having a minimum value of the energy value of the effective frame length of 20 ms as a reference value and compares the energy of the received frame of the message data with the minimum energy value of the effective frame of 20 ms length to generate a second detection signal of the frame when the energy value the received message data frame is above the minimum energy value of the effective frame of 20 ms in length.  20. A device for receiving data on a dedicated control channel for a CDMA system having at least two different frame lengths, comprising a compressor for compressing a signal received on a dedicated control channel; a first frame detector for detecting the energy of the compressed signal, characterized by a first frame length and issuing a first frame detection signal in accordance with the result of detecting the frame; a second frame detector for detecting the energy of a compressed signal characterized by a second frame length and issuing a second frame detection signal in accordance with the result of detecting the frame; a first message receiver for deinterleaving and decoding the compressed signal, characterized by a first frame length and issuing a first message, and for detecting a first CRC detection signal corresponding to a decoded signal, with the possibility of issuing a first CRC detection signal; a second message receiver, designed for de-interleaving and decoding the compressed signal, characterized by a second frame length and issuing a second message, and for detecting a second CRC detection signal corresponding to the decoded signal, with the possibility of issuing a second CRC detection signal, and a controller for selecting between the first and second messages in accordance with the first and second frame detection signals and the first and second CRC detection signals.  21. The device according to p. 20, characterized in that the first and second lengths of the message data frame are 5 and 20 ms, respectively.  22. The device according to p. 20, characterized in that the controller comprises a frame decision block for analyzing the first and second CEC detection signals and the first and second frame detection signals, with the possibility of determining that the received frame has a second frame length message data, based on the received second CEC detection signal and the second frame detection signal, with the possibility of determining that the received frame has a first message data frame length, based on the received first signal identifying the CRC and the first frame detection signal, and to determine that the received frame is an erroneous frame, based on other received CRC and frame detection signals, and a selector designed to output respectively one of the decoded signals issued by the first and second message receivers upon receipt either the first or second decision signal on the frame, and to control the output of the decoded signal when receiving a decision signal on the presence of an erroneous frame.  23. The device according to p. 22, characterized in that the decision block on the frame is configured to determine the absence of reception of any frame in the absence of reception of the first and second detection signals of the frame, as well as the first and second detection signals of the CEC.  24. The device according to p. 21, characterized in that the first frame detector has a minimum value of an effective frame energy of 5 ms as a threshold value and is configured to compare the energy value of a received frame message with a minimum energy value of an effective frame of 5 ms and generating the first a frame detection signal when the energy value of the received message data frame is higher than the minimum energy value of the effective frame of 5 ms in length, the second frame detector having as a threshold the minimum energy value of the effective frame length of 20 ms and is configured to compare the energy of the received frame of the data message with the minimum energy value of the effective frame of 20 ms and generate a second frame detection signal when the energy value of the received frame of the message data is higher than the minimum energy value of the effective frame of length 20 ms  25. A method of receiving data in a CDMA communication system having at least two different frame lengths, comprising the steps of compressing a signal received on a dedicated control channel; reverse interleaving of a compressed signal having a first frame length, decoding an interleaved signal and having a first frame length, detecting a first CRC detection signal corresponding to a decoded signal, and issuing a first message, reverse interleaving a compressed signal having a second frame length, decoding a signal, interleaved and characterized by a second frame length, detecting a second CEC detection signal corresponding to ekodirovannomu signal and issuing a second message, selects between the first and second messages according to first and second CRC detection signals.  26. A method of receiving data in a CDMA communication system having at least two different frame lengths, in which the signal received on the dedicated control channel is compressed, the energy of the compressed signal characterized by the first and second frame lengths is detected, and the first and second frame detection signals in accordance with the results of frame detection, while performing reverse alternation of the compressed signal, characterized by the first and second frame lengths, decoding the signals subjected to alternating the first and second second frame lengths and choose between the first and second messages in accordance with the first and second frame detection results.  27. A method of receiving data in a CDMA communication system via a dedicated control channel, wherein the signal received on the dedicated control channel is compressed, energy is detected for the compressed signal, characterized by the first frame length and the first frame detection signal is generated in accordance with the frame detection result, energy detection a compressed signal, characterized by a second frame length and the issuance of a second frame detection signal in accordance with the result of detecting a frame, perform reverse alternation the compressed signal, characterized by the first frame length, decode the signal subjected to deinterleaving, characterized by the first frame length, detecting the first signal of the CEC detection corresponding to the decoded signal, and issuing the first message, reverse the interleaved compressed signal, characterized by the second frame length, decode the signal subjected deinterleaving, characterized by a second frame length, detect the second CEC detection signal, respectively the current decoded signal, the second message is issued and a choice is made between the first and second messages in accordance with the first and second frame detection results and the first and second CRC detection signals. Priority on points:
02/14/1998 PP 1-15, 25;
04/18/1998 PP 16-24 and 26 and 27.

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