KR100703436B1 - Apparatus and method for user identification of high data rate packet transmission channel at mobile communication system - Google Patents

Abstract

The present invention relates to an apparatus and method for classifying a user of a packet transmission channel using a preamble channel in a high speed packet transmission mobile communication system. In particular, the present invention relates to a frame structure of a channel for smoothly transmitting a user index and a user identification. By providing a method of transmitting more indexes through an index transmission channel and a receiver of a terminal capable of accurately distinguishing packet data by detecting a transmitter and an index of a base station according to the index transmission channel, a high-speed service for simultaneously serving a voice channel and a data channel Packet Data Transmission In the mobile communication system, there is an advantage of quickly transmitting user index information for packet users while using a minimum Walsh channel.

High speed packet data transmission channel, user discrimination, user index, preamble, mobile communication system

Description

Apparatus and method for distinguishing a user of a high speed packet data transmission mobile communication system {APPARATUS AND METHOD FOR USER IDENTIFICATION OF HIGH DATA RATE PACKET TRANSMISSION CHANNEL AT MOBILE COMMUNICATION SYSTEM}             

1 is a diagram illustrating a configuration of a forward link transmitter for a data traffic channel according to an embodiment of the present invention.

2 is a diagram illustrating a frame structure of a user index transmission channel for distinguishing users of a fast packet data transmission channel according to an exemplary embodiment of the present invention.

3 is a diagram illustrating a transmitter structure of a base station for transmitting a user index transmission channel in a high speed packet data transmission mobile communication system according to an exemplary embodiment of the present invention.

4 is a diagram illustrating a receiver structure of a terminal for demodulating a user index transmission channel in a high speed packet data transmission mobile communication system according to an exemplary embodiment of the present invention.

5 is a diagram illustrating a control flow for allocating a user index in a base station of a fast packet data transmission mobile communication system according to an embodiment of the present invention.

The present invention relates to an apparatus and method for identifying a user of a packet transmission channel in a high speed packet transmission mobile communication system, and more particularly, to an apparatus and a method for distinguishing a user using a preamble channel.

In general, a high-speed packet transmission mobile communication system can be broadly classified into a type that supports only a data channel and a type that simultaneously supports a voice channel as well as a data channel. A high speed packet transmission mobile communication system supporting only the data channel is called an IMT-2000 1xEV / DO system, and a high speed packet transmission mobile communication system supporting both a data channel and a voice channel simultaneously is called an IMT-2000 1xEV / DV system. It is called.

Meanwhile, the high speed packet transmission mobile communication system can use a high speed packet data transmission channel for high speed data service. The high-speed packet data transmission channel allows multiple users to use the same channel by time division multiplexing (TDM) in order to enable high-speed data transmission. In addition, the high speed packet transmission mobile communication system as described above requires an index indicating which user is the data transmitted on the high speed packet data transmission channel. To this end, the current IMT-2000 1xEV-DO system standard uses 32-ary Walsh functions to distinguish users. That is, conventionally, a method of covering and de-covering the preamble by the 32-ary Walsh function is used to distinguish users. The preamble refers to a part of transmitting a value of binary 1 for a specific time prior to transmitting a high speed packet data transmission channel.

In more detail, the transmitter of the base station spreads and transmits the preamble by one of the 32 Walsh functions having a length of 32. Meanwhile, the receiver of the mobile terminal distinguishes the user by despreading the spread preamble from the transmitter of the base station using the Walsh function assigned to the user among the 32 Walsh functions of the length 32. That is, when a corresponding value is detected by the despreading, the receiver of the mobile terminal recognizes that the packet data transmitted after the preamble is its own and performs demodulation.

As described above, a maximum of 64 users can be distinguished by using 32 Walsh functions having a length of 32 and 32 bi-orthogonal Walsh functions of the Walsh functions as described above. In other words, all 32 bi-orthogonal Walsh functions were used to distinguish up to 64 users.

Even if a user is distinguished using the conventional method as described above, a problem does not occur in a 1xEV / DO system that does not provide a voice service to a user through a voice channel. However, in the 1xEV / DV system capable of simultaneously supporting a voice service and a packet data service, there is a problem in that a voice service cannot be provided to a user by the above-described conventional method. That is, when a maximum of 64 users are distinguished using all 32-ary bi-orthogonal Walsh functions, the Walsh function for voice service becomes impossible. On the contrary, when a given user is receiving a voice service, the user index for the packet data user is limited, which causes a problem of reducing the number of accessible users of the packet data service.

As described above, the conventional user discrimination method is applicable to a 1xEV / DO system in which only a data channel for data service exists. However, it is not applicable to the 1xEV / DV system in which a voice channel for voice service coexists with the data channel. That is, when a user is distinguished using all 32 Walsh functions during a period in which a preamble is transmitted in a 1xEV / DV system like a 1xEV / DO system, a voice user may not receive a call service during the period.

Accordingly, an object of the present invention to solve the above problems is to provide an apparatus and method that can distinguish as many packet data channel users as possible while consuming fewer Walsh functions for voice users.

It is another object of the present invention to distinguish as many packet data users as possible while consuming minimal Walsh resources of the system for voice users in a 1xEV-DV mobile communication system in which a high speed packet data channel can be transmitted simultaneously with the voice channel. A method of improving the frame structure of a preamble channel is provided.

It is still another object of the present invention to distinguish as many packet data users as possible while consuming the minimum Walsh resources of the system for voice users in a 1xEV-DV mobile communication system in which high-speed packet data transmission is serviced simultaneously with the voice channel. The present invention provides a transmitter apparatus and a method of a base station.

It is still another object of the present invention to distinguish as many packet data users as possible while consuming the minimum Walsh resources of the system for voice users in a 1xEV-DV mobile communication system in which high-speed packet data transmission is serviced simultaneously with the voice channel. The present invention provides a receiver apparatus and method for a terminal capable of distinguishing a user by demodulating a frame of a preamble transmitted by the base station transmitter to the terminal.

It is still another object of the present invention to distinguish as many packet data users as possible while consuming the minimum Walsh resources of the system for voice users in a 1xEV-DV mobile communication system in which high-speed packet data transmission is serviced simultaneously with the voice channel. The present invention provides a method of a base station for determining a user index.

DETAILED DESCRIPTION Hereinafter, detailed descriptions of preferred embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the same reference numerals in the drawings denote the same reference numerals, even if shown in different drawings.

In the following description, specific details, such as the length or number of Walsh functions for distinguishing users of high-speed packet data, are shown to provide a more general understanding of the present invention. It will be apparent to those skilled in the art that the present invention may be readily practiced without these specific details or by modifications thereof.

In addition, the forward link used in the following description means a link transmitted from the base station to the terminal, the reverse link means a link transmitted from the terminal to the base station.

1 is a diagram illustrating a configuration of a forward link transmitter for a data traffic channel according to an embodiment of the present invention. The forward link transmitter for the data traffic channel transmits the preamble subchannel (PSCH) signal, the data traffic subchannel (DTSCH) signal, and the pilot channel (PICH) signal by time division multiplexing (TDM). It is done.

Referring to FIG. 1, a preamble symbol having a value of '0' is input to a signal point mapper 101 and mapped to '+1'. The output symbol of the signal point mapper 101 is input to the Walsh spreader 102 and is a specific 64-ary bi-orthogonal Walsh corresponding to a user's unique MAC identifier (ID) (or index). Spread by code (or sequence). The Walsh spreader 102 outputs a sequence of a first channel and a sequence of a second channel. The output sequence of the Walsh spreader 102 is input to a sequence repeater 103 and subjected to sequence repetition according to a transmission rate. The sequence repeater 103 may repeat the output sequence of the Walsh spreader 102 up to 16 times according to the transmission rate. Therefore, the PSCH included in one slot of the DTCH may last from 64 chips up to 1,024 chips depending on the transmission rate. The output (I, Q) sequence of the sequence repeater 103 is input to a time division multiplexer 130 and multiplexed with the PICH and DTSCH.

The channel coded bit sequence is input to the scrambler 111 and scrambled. The output sequence of the scrambler 111 is input to the channel interleaver 112 and interleaved. In this case, the size of the channel interleaver 112 is also applied differently according to the size of the physical layer packet. The output sequence of the channel interleaver 112 is input to the M-ary symbol modulator 113 and mapped into M-ary symbols. The M-ary symbol modulator 113 operates as a quadrature phase shift keying (QPSK), a phase shift keying (8-PSK), or a quadrature amplitude modulation (16-QAM) modulator according to a transmission rate, and a physical layer packet unit whose transmission rate can be changed. The modulation method can also be changed. The (I, Q) sequence of M-ary symbols output from the M-ary symbol modulator 113 is input to a sequence repeater / symbol puncturer 114, and the sequence repetition / symbol punctures according to the transmission rate. The (I, Q) sequence of M-ary symbols output from the sequence repeater / symbol puncturer 114 is input to a symbol demultiplexer 115. The (I, Q) sequences of M-ary symbols input to the symbol demultiplexer 115 are demultiplexed into N Walsh code channels available for DTSCH and output. The number N of Walsh codes used for the DTSCH is variable, and information about this is broadcasted through the WSISCH, and the terminal determines the transmission rate of the base station in consideration of this information and requests the base station. Accordingly, the UE can know the allocation status of the Walsh code used for the currently received DTSCH. Output (I, Q) symbols of the symbol demultiplexer 115, which are demultiplexed into N Walsh code channels and output, are input to the Walsh spreader 116 and spread by a specific Walsh code for each channel. The output (I, Q) sequences of the Walsh spreader 116 are input to a Walsh Channel Gain Controller 117, are gain controlled, and then output. The N output (I, Q) sequences output from the Walsh channel gain controller 117 are input to the Walsh Chip Level Summer 118, added in chip units, and then output. The (I, Q) chip sequence output from the Walsh chip summer 118 is input to the time division multiplexer 130 and multiplexed with PICH and PSCH.

The pilot symbol may have only a value of '0'. The pilot symbol is input to the signal point mapper 121 and mapped to '+1'. The output symbol of the signal point mapper 121 is input to a Walsh spreader 122. The output symbols of the signal point mapper 121 input to the Walsh spreader 122 are spread by a particular 128-ary Walsh code assigned to the PICH. The output sequence of the Walsh spreader 122 is input to the PICH gain controller 123 and gain controlled after being output. The chip I sequence output from the PICH gain controller 123 is input to the time division multiplexer 130 and multiplexed with a PSCH and a DTSCH.

The time division multiplexer 130 multiplexes the I channel signal of the PICH, the I channel signal of the DTSCH, and the I channel signal of the PSCH and outputs the A signal. The I channel signal of the PICH is an I sequence from the sequence repeater 103, the I channel signal of the DTSCH is an I sequence from the Walsh chip summer 118, and the I channel signal of the PSCH is an output signal of the gain controller 123. The time division multiplexer 130 multiplexes the Q-channel signal of the PICH, the Q-channel signal of the DTSCH, and the Q-channel signal of the PSCH and outputs the B-channel signal. The Q channel signal of the PICH is the Q sequence from the sequence repeater 103, the Q channel signal of the DTSCH is the Q sequence from the Walsh chip summer 118, and " 0 " is input to the Q channel signal of the PSCH.

Quadrature spreader 150 uses a spreading sequence consisting of a first channel (I-ch) spreading sequence and a second channel (Q-ch) spreading sequence to complex spread the input signal consisting of the complex output of the multiplexer 130. After complex spreading (or complex multiplying), the first channel I-ch signal and the second channel Q-ch signal are output. The first channel I-ch signal from the quadrature spreader 150 is input to the low pass filter 161 and low pass filtered. The second channel Q-ch signal from the quadrature spreader 150 is inputted to the low pass filter 162 to be low pass filtered. The output of the low pass filter 161 is input to the frequency shifter 171 and shifted to the RF band by the product of the first frequency cos2fct, and the output of the low pass filter 162 is input to the frequency shifter 172 and multiplied by the second frequency sin2fct. Transition to the RF band. Summer 180 adds the output signal of frequency shifter 171 and the output signal of frequency shifter 172. The summation signal by the summer 180 is emitted through an antenna (not shown).

2 illustrates a structure of a forward link data traffic channel for a packet data service according to an exemplary embodiment of the present invention. Referring to FIG. 2, the minimum transmission unit of the physical layer for packet data service is a slot consisting of 1,536 chips, which has a duration of 1.25 msec.

Referring to FIG. 2, one slot of a data traffic channel (DTCH) is divided into two half slots composed of 768 chips. The first 128 chip section of each half slot is allocated to a pilot channel (PICH) for inserting a pilot symbol. The remaining 640 chips except the portion allocated to the PICH in each half slot are allocated to a data traffic subchannel (DTSCH) for payload. In the case of an idle slot in which no payload exists, the DTSCH is gated off to reduce interference to a service connected to a dedicated line and adjacent base station signals. Meanwhile, as shown in FIG. 1, a preamble subchannel (PSCH) is multiplexed with a PICH and a DTSCH and transmitted through a DTCH. Since the PSCH is used for the purpose of designating a corresponding terminal for a data packet transmitted by a base station, the PSCH must exist in the first slot of the DTCH for transmission of a physical layer packet. The preamble symbol may have only a value of '0'.

The function and operation of the preamble channel according to the present invention will be described in detail with reference to FIG. 2.

As shown in FIG. 2, the preamble channel is inserted into the fast packet data transmission channel by TDM. The base station transmits a user index for distinguishing a user through a preamble channel before transmitting the packet data. Meanwhile, the terminal distinguishes the user from the packet data by using the user index inserted in the preamble channel. The present invention adopts a method using a Walsh function in the method of inserting a user index into the preamble channel to improve the conventional method.

Next, a transmission and reception apparatus for transmitting a user index using a Walsh function on a preamble channel according to an embodiment of the present invention will be described in detail with reference to FIGS. 3 and 4.

3 is a diagram illustrating a configuration of a transmitter of a base station transmitting a user index on a preamble channel according to an embodiment of the present invention. Referring to FIG. 3, the controller 301 receives a user index from an upper layer (not shown), and selects a Walsh function to be used for spreading the preamble based on the provided user index. At this time, the length of the Walsh function selected from the controller 301 is as defined in the 1xEV / DV standard document. In the present invention, the Walsh function having a length of 64 will be described as an example. According to the present invention, the maximum length of 256 users can be distinguished using the 64 length Walsh function.

The packet user index transmission method of the present invention will be described with Equation 1 described below with reference to the operation of block 301 shown in FIG.

An example of an operation of selecting the Walsh function by the user index in the controller 301 may be expressed by Equation 1 below.                     

 According to the user index assigned to the user by the base station, each user distinguishes the user by using his Walsh function or the complement of the Walsh function. For example, if the user index i assigned to a specific user is 33, the user distinguishes the user index by using a complement of 64 Walsh functions eight times. Since 33 mod 4 is 1, the Walsh function corresponding to the complement of 64 Walsh function number 8 is transmitted to the I channel. According to the present invention, one Walsh channel can be used as a bi-orthogonal Walsh function after four users are divided into I or Q channels. The above-described method enables the use of a Walsh channel four times more efficient than the conventional method using only orthogonal functions. Thus, the present invention enables twice the efficient use of the Walsh channel compared to the conventional method of the 1xEV / DO system using only a bi-orthogonal function.

The spreader 302 selects an I-channel or a Q-channel from the preamble signal from the signal point mapper, and spreads the preamble signal to a Walsh function selected by the controller 301. The output from the spreader 302 transmits a signal only in I or Q channel for one packet transmission unit (1.25 ms slot in case of 1xEV / DV).

4 is a diagram illustrating a receiver of a terminal for distinguishing a user index of a fast packet data transmission channel according to an exemplary embodiment of the present invention. A method of distinguishing a user index in a receiving apparatus according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 4 as follows.

The controller 401 illustrated in FIG. 4 receives a user index from an upper layer (CPU, not shown) and selects a Walsh function according to its index according to Equation (1). The controller 401 transmits the selected Walsh function and I or Q channel information to the despreader 402. The despreader 402 inputs a received signal despread by a predetermined pseudo noise (hereinafter, referred to as "PN"), and inverts an I channel or a Q channel using a Walsh function selected by the controller 401. Spread. The despread information is sent to detector 403. The detector 403 accumulates the despread information from the despreader 402 for 64 pn chips and determines the index as its index when the value exceeds a specific threshold. The determined information is transmitted to the data symbol demodulator 404 to start demodulation of the received signal.

5 is a diagram illustrating a method of determining a user index in a transmission apparatus of a base station according to an embodiment of the present invention. Hereinafter, a method of allocating an index for a packet user in consideration of the Walsh usage of the system will be described in detail with reference to FIG. 5.

First, in step 501, the transmitting apparatus of the base station detects and stores the Walsh channel usage status of the voice user currently used in the system. In step 502, the transmitter of the base station calculates the Walsh channel for the packet user index in consideration of the Walsh channel of the voice user stored by performing the step 501. In step 503, the transmitting apparatus of the base station determines the packet user index using the Walsh channel for the packet user index calculated in step 502 and Equation 1. In step 504, the transmitter of the base station transmits the packet user index determined in step 503 to the mobile station through a control message.

As described above, the present invention enables a large number of user indexes to be transmitted using a limited Walsh channel in a high speed packet data transmission mobile communication system, and a voice even in a 1xEV / DV system that simultaneously supports a voice user and a high speed packet data transmission channel. There is an advantage of quickly transmitting user index information for packet users with minimal use of Walsh channels for users.

Claims (5)

A transmission apparatus of a base station for distinguishing users in a high speed packet data transmission mobile communication system having a signal point mapper for mapping preamble symbols to predetermined information and outputting the same; A control unit for inputting a user index from an upper layer and outputting a channel selection signal with selection of a Walsh function having a predetermined length for spreading a preamble by the user index; The preamble symbols mapped to the predetermined information from the signal point mapper are switched to the I channel or the Q channel by the channel selection signal received from the controller, and the switched preamble symbols are transferred to the Walsh function selected by the controller. And a spreader spreading by a user. The method of claim 1, The controller receives the user index i from the upper layer and selects a Walsh function having a predetermined length to spread the preamble as shown in Equation 2 using the received user index. A user discriminating apparatus for a high speed packet data transmission mobile communication system.

High-speed packet data including a PN despreader for despreading and outputting a spread received signal received through an antenna by a predetermined pseudo noise (hereinafter referred to as "PN"), and simultaneously serving a voice channel and a data channel. In the receiving device of the terminal for distinguishing users in the transmission mobile communication system, A control unit for inputting a user index from an upper layer and outputting a channel selection signal with a selection of a Walsh function of a predetermined length for despreading the PN despread signal received by its own index among the user indices; The PN despread signal received from the PN despreader is switched to an I channel or a Q channel by the channel selection signal from the controller, and the switched signal is inversed by the Walsh function from the controller. Diffuser with diffuser, A detector which accumulates the despread preamble symbol from the despreader by the length of the predetermined PN, and compares the accumulated value with a specific threshold value to determine whether the preamble symbol is its index; And a data symbol demodulator for demodulating the received signal provided from the detector when the preamble is determined to be an index of the preamble. The method of claim 3, The control unit selects a Walsh function having a predetermined length for spreading the preamble by applying its index (i) among the user indices from the upper layer to Equation 3 below. User distinguishing device in mobile communication system.

A method of determining a user index for user discrimination in a base station transmitter of a high speed packet data transmission mobile communication system that simultaneously services a voice channel and a data channel, Detecting Walsh channel usage of the voice channel used in the mobile communication system; Calculating a Walsh channel for a packet user index in consideration of the Walsh channel used as the detected voice channel; Determining a packet user index based on the calculated Walsh channel for the packet user index and Equation 4 below; And transmitting the determined packet user index to a terminal through control information.

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