KR100797462B1 - Method for transmitting a packet data in Communication System - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system, and more particularly, to a method of transmitting packet data. The packet data transmission according to the present invention is a Walsh for data transmission in a mobile communication system using a time division scheme and a code division scheme. Prioritizing and sorting codes; Including and transmitting a Walsh code information field used in the data transmission from the sorted Walsh codes in a control channel; And receiving and decoding the data according to the transmitted Walsh code information.

CWSI, WSI

Description

Method for transmitting a packet data in a communication system

1 is a diagram illustrating an example of a TDM packet transmission used in the present invention.

2 is a diagram showing an example of a packet transmission of the CDM / TDM scheme used in the present invention.

3 is a diagram illustrating an example of a transmission chain configuration of an S-DPCCH according to the present invention.

4 is a diagram illustrating another example of a transmission chain configuration of an S-DPCCH according to the present invention.

The present invention relates to a mobile communication system, and more particularly, to a method of transmitting packet data.

Conventional wireless communication systems for packet data transmission use a physical channel such as a packet data channel (PDCH) and a packet data control channel (PDCCH) for packet data transmission.

The PDCH is actually a channel for transmitting packet data to be transmitted to the corresponding terminal (or user, hereinafter referred to as terminal). Several users divide the PDCH in time division multiplexing (TDM). The PDCCH includes control information that enables the terminal to properly receive data transmitted through the PDCH without error. The PDCCH uses two types, a primary PDCCH (P-PDCCH) and a secondary PDCCH (S-PDCCH). Of these, S-PDCCH is essentially used, and P-PDCCH is optionally used.

When the base station transmits packet data in a TDM manner by ordering the data to be transmitted to each terminal, the packet data transmitted to each terminal always uses available resources (i.e., Walsh codes used) allocated to the PDCH channel. Use them all. As a result, even if only a part of the available resources is needed, the use of all of them may result in waste of resources.

In addition, in the packet data transmission scheme based on the TDM scheme, the base station notifies Walsh code usage information to all terminals managed by the base station periodically or aperiodically in a broadcast form. At this time, the base station uses all the power available to all terminals (including the terminal in the harshest environment) to receive this Walsh code usage information, which causes waste in terms of power.

Furthermore, if the Walsh code usage information changes frequently and needs to be notified frequently, the PDCH cannot be transmitted at the time of transmitting the Walsh code usage information, thereby reducing the overall transmission efficiency of the system.

Accordingly, the present invention has been made in view of the above-mentioned problems of the prior art, and is to provide a method for transmitting packet data that prevents waste of transmission power.

In addition, the present invention is to provide a packet data transmission method for increasing the resource utilization efficiency.

The present invention also provides a packet data transmission method in a system in which time division and code division multiplexing are used.

According to an aspect of the present invention for achieving the above object, in a mobile communication system using a time division method and a code division method, in a mobile communication system using a time division method and a code division method, Prioritizing and sorting Walsh codes; Including and transmitting a Walsh code information field used in the data transmission from the sorted Walsh codes in a control channel; And receiving and decoding the data according to the transmitted Walsh code information.

Hereinafter, a configuration and an operation according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

Prior to describing the present invention, the parameters used in the present invention are described below.

In the present invention, the above-described Walsh code (walsh code), PDCH, and PDCCH are used. Here, the Walsh code, PDCH, PDCCH is not limited to the name, and represent the same function code or channels. In addition, a newly defined physical channel NPDCCH (hereinafter referred to as NPDCCH) is used to additionally transmit control information not included in the conventional control channel.

The Walsh code space (Walsh code space) is a collection of Walsh codes currently available when the base station transmits packet data. The elements change over time.

Walsh_Max is the maximum number of Walsh codes that can be included in the Walsh code space, and the value changes over time.

Walsh (all) is a parameter indicating all Walsh codes in the Walsh code space.

PDCH (i) means the i-th PDCH when it is possible to use two or more PDCHs. In this case, each PDCH uses Walsh codes in Walsh code space separately.

For example, if up to four PDCHs are available in a system, PDCH (0), PDCH (1), PDCH (2), PDCH (3) are possible, and PDCH scheduled to transmit packet data at some point in time They share the Walsh code space. However, if only one PDCH is scheduled, the PDCH uses Walsh (all). On the other hand, when PDCH (0) and PDCH (3) are used at the same time, these two PDCHs divide Walsh code space, and the Walsh codes they use are defined as Walsh (0) and Walsh (3), respectively.

Walsh (i) is a set of Walsh codes used by PDCH (i) at a specific transmission time. This element consists of elements in the Walsh code space. Although the Walsh code space does not change, the Walsh code belonging to Walsh (i) changes over time. That is, Walsh (i) of the previous time and Walsh (i) of the current time have different constituent elements and number of elements. The Walsh code usage unit of Walsh (i) is x, and the number of elements of each Walsh (i) is a multiple of x. 1x, 2x, 3x, etc. The number of elements in Walsh (i) is independent of the number of Walsh (all).

N _{max_PDCH} is the maximum number of PDCH or PDCCH that the system or sector can use.

N _{real_PDCH} is the number of PDCH or PDCCH that the system or sector uses at a given time.

As shown in FIG. 1, the TDM packet data is transmitted in a time division manner by determining the order of data to be transmitted to each terminal. Here, the base station always uses all Walsh code space for the PDCH.

In FIG. 1, the length of time of the transmission unit on the PDCH and the PDCCH is fixed or variable. In addition, the transmission unit time lengths of the PDCH and the PDCCH do not necessarily have to match. user k implies packet data or control information for user k (or terminal k). Transmission of the PDCH and PDCCH for the user k is determined according to a specific rule, the transmission time and the transmission length. Here, the time interval between transmission of PDCH and PDCCH for each user may or may not exist depending on the system environment.                     

In the CDM / TDM packet data transmission, as shown in FIG. 2, the base station determines the order of data to be transmitted to each terminal (scheduling), and transmits the data in the time division (TDM) and code division (CDM) methods. In this manner, only one PDCH may be transmitted at a time of transmission, and several PDCHs may be transmitted.

When one PDCH is transmitted, Walsh (all) is used for this PDCH. When two or more PDCHs are transmitted, each PDCH uses Walsh codes in Walsh code spaces separately. That is, each PDCH (i) uses Walsh (i). PDCH (i) has PDCCH (i) which is a PDCCH having control information corresponding to each.

The terminal monitors the PDCCH (i), finds out what form of packet data is transmitted through which PDCH (i), and can receive the corresponding information. The transmission unit time lengths of the PDCH (i) and the PDCCH (i) do not necessarily need to match.

2 illustrates an example in which up to four PDCHs may exist in a CDM / TDM scheme. Here, the time lengths of the transmission units on the PDCH (i) and the PDCCH (i) are fixed or variable. There may or may not be a time interval between transmissions of PDCH or PDCCH for each user. In FIG. 2, the empty space is a case where PDCH or PDCCH is not used. In the transmission period (a), four PDCH (i) are transmitted, and four PDCCH (i) are used. In the transmission period (b), three PDCH (i) are transmitted, and three PDCCH (i) are used. In the transmission period (c), three PDCH (i) are transmitted, and three PDCCH (i) are used. In the transmission period (d), one PDCH (i) is transmitted and one PDCCH (i) is used. In the transmission period (e), four PDCH (i) are transmitted, and four PDCCH (i) are used.

The present invention proposes a structure of a new control channel in order to use the CDM / TDM scheme as shown in FIG. 2, and names it N-PDCCH, and proposes an efficient operation method of the proposed control channel.

First, in order to support a packet data transmission system of a TDM / CDM method, information on walsh (i) used by each PDCH (i) must be informed to the terminal. For this purpose, a new control channel N-PDCCH is proposed. Hereinafter, information transmitted through the N-PDCCH is referred to as WSIC. This WSIC has the number of information bits x_N. This WSIC contains information about walsh (i) used by each PDCH (i). That is, information on which PDCH (i) uses which of the codes in the Walsh code space. The number of bits of the WSIC, x_N, is used for each PDCH (i when up to N PDCH (i) are used on any time axis (for example, when there are N PDCH (i) at which a new transmission is started on any time axis). ) Is the number of bits required to inform the terminals of the information of walsh (i) being used, which varies depending on the N value. The x_N value for each N and the method of interpreting the WSIC are promised in advance between the base station and the terminal (or transmitting end and receiving end).

The time length of this N_PDCH transmission unit is an integer multiple of one slot. Here, the slot is the minimum basic unit of the time length of the transmission unit, and the time length of the transmission unit of the PDCH (i) and the S-PDCCH (i) is also one of the multiples of the slot. If one slot is 1.25 msec, the time length of the transmission unit of the N_PDCH may be 1.25 msec, 2.5 msec, 3.75 msec, 4 msec, or the like. Hereinafter, for convenience of explanation, it is assumed that it is fixed at 1.25 msec.

3 is a diagram illustrating a transmission chain configuration of an N-PDCCH according to the present invention.

Referring to FIG. 3, the input sequence of the forward N-PDCCH includes the WSIC of the x_N bits. The number of bits of x_N is variable according to N, and N is an integer increasing to 1, 2, 3, etc., and the number of PDCH (i) per slot (or a new transmission starts at a specific time point). Number of PDCH (i)).

The input sequence is input to the error detection encoder 101 to which an error detection code such as a CRC is added. The error detection encoder 101 can be omitted as a part for generating bits indicating whether an error has occurred during transmission.

The sequence to which the CRC is added is input to the error correction encoder 102 to perform channel coding. This channel coding is the part that generates the bits that make it possible to correct an error occurring in transmission.

The sequence to which the error correction bits are added is output by repeating or removing each of the symbols in the symbol repetition and / or puncturing block 103 according to a specific rule, or both, which are one slot for different number of input bits. This is the part that allows a fixed number of bits (ie L bits) to occur.

This repeated and / or punctured sequence is interleaved in the block interleaver 104 and output. This interleaving procedure is to prevent burst errors in the fading channel.                     

The interleaved sequence is modulated by the QPSK scheme in modulator 105, and the modulated signal is separated into an I channel and a Q channel using some of the Walsh codes indicated by the WSIC.

In FIG. 3, w_i ^ M denotes an i th code of Walsh codes having a length of M. In FIG. In this case, L and M are values that are correlated with each other according to the time length of one chip of the Walsh code. For example, when the time length of one chip of the Walsh code is 1/1228800 and M = 64, L = 48 according to the following equation.

In FIG. 3, each of the blocks 101, 102, 103, and 104 may vary according to the value of x_N in order to generate fixed L bits per slot for different number of input bits. For example, the coding rate of the error correction encoder 102 or the type of encoder may be different according to the value of x_N.

Therefore, in order for the terminals to receive the N-PDCCH without error, the terminal must find out the value of x_N that is currently being transmitted. The value of x_N may be known to terminals through a signaling method or a broadcast method. Alternatively, the terminal may know through differentiation of the transmission scheme of the N-PDCCH.

For example, the error detection encoder 101 of FIG. 3 is referred to as an encoder to which a CRC code is added, and generates a CRC bit under the assumption that an x_N value is promised for each N value between the base station and the terminal. In this case, the initial values of the transition registers constituting the encoder to which the CRC code is added are defined for each predefined x_N value, and then used. At this time, the terminal repeats the decoding process using initial values of a predetermined number of transition registers known in advance. If the decoding succeeds, the x_N value corresponding to the initial values of the transition registers used for decoding can be known.

Since the terminal knows the current N value by knowing the x_N value, the terminal can additionally use this information.

4 is a diagram illustrating an example of a transmission chain configuration of an N-PDCCH according to the present invention when Nmax_PDCH = 4.

Referring to FIG. 4, the input sequence of the forward N-PDCCH includes the WSIC of the x_N bits. The number of bits of this x_N varies with N, and N is 1, 2, 3, or 4.

The input sequence is appended with an error detection code, such as a cyclic redundancy check (CRC) code, in error detection addition block 201. The bits to which this error detection code is added are the number of 5 * N + 6 bits.

This added bit is then added with tail bits to send the final state of the encoder to a known termination in the tail bit addition block 202. The bit with this tail bit added is the number of 5 * N + 14 bits. The bits to which the tail bits are added are encoded by the convolutional code in the encoder 203. This sign bit is 10 * N + 28.

When the encoded bits have N equal to 1, 10 symbols of the input bits are repeated in the symbol repetition block 204.

The repeated bits are punctured in puncturing block 205. If N is 3 or 4, the punctured symbol is a 10 * (N-2) symbol.

The punctured bits are interleaved in the block interleaver 206 and modulated by the QPSK scheme in the modulator 207. This modulated signal is separated into an I channel and a Q channel using some of the Walsh codes indicated by the CWSI.

The interleaved signal has 48 symbols (38.4ksps) per slot.

Operation examples of the new channel N-PDCCH proposed as described above are as follows.

First example

First, when only the TDM scheme is used without using the CDM, and the conventional Walsh code usage information (WSI) broadcasting method (when the control channel is used as a broadcasting channel) is used, that is, when N _{max_PDCH} is 1 This is an example of operation. Only one PDCH (i) and S-PDCCH (i) are used here. In the following, i is assumed to be 0.

Here, the N-PDCCH is not transmitted. Accordingly, the Walsh code usage information (WSI) is broadcast to the terminals using the S-PDCCH (0) according to the conventional scheme.

Second operation example

In this case, only the TDM method is used without using the CDM, and the conventional WSI broadcasting method is not used. Similarly, N _{max_PDCH} assumes 1, and only one PDCH (i) and S-PDCCH (i) are used. In addition, I assumes 0 below.

In this case, unlike the first operation example, the N-PDCCH is transmitted to the corresponding terminal when necessary. The value of x_N is the number of bits necessary to inform the information of the Walsh code being used to transmit the PDCH (0), and is the number of bits previously reserved for the case of N = 1.

Here, WSIC plays the same role as the existing WSI. However, unlike the conventional method, the WSI broadcast method is not used. Instead, the terminal knows the current Walsh space code through the WSIC. The transmit power of the N-PDCCH uses a size enough to allow the terminal to receive the PDCH (i) currently being transmitted to successfully receive the N-PDCCH.

Third operation example

In this case, it is assumed that N _{max_PDCH} is 1 or more when CDM is used and a conventional WSI broadcasting method is used. It is _assumed that at most one time, only N _{max_PDCH} PDCH (i) and S-PDCCH (i) are used, and i is 0, 1, and (N _{max_PDCH-} 1).

In this case, the N-PDCCH is transmitted to the corresponding terminal when necessary. In addition, the WSI is broadcast to the terminals using any one or several of the N S-PDCCH (i). The value of x_N is as many bits as necessary to inform the terminals of which Walsh codes are being used to transmit the N PDCH (i) being transmitted at a particular point in time. At this time, as described above, the value of x_N is promised for each N in advance.                     

In this case, the information indicated by the WSIC is about which Walsh codes are used to transmit the N PDCH (i) being transmitted at a particular point in time. Separately, because the WSI broadcast method is used, the WSIC information does not contain information about the current Walsh code space.

Table 1 below shows Walsh code lists in the case of using the CDM and the conventional WSI broadcasting method. walsh_Max = 28, where the current Walsh code space consists of 25 codes, starting from the highest priority code on the code priority table to the lowest priority code.

Table 1a is a table where N is 2. That is, when i and j are not the same, when the Walsh (i) and Walsh (j) used by the two PDCH (i) and PDCH (j) is shown in Table 1a, only the information about the PA WSIC is It is included. In Table 1a, WSI information is transmitted to terminals through a conventional broadcast method.

Table 1b is a table where N is three. That is, when i, j and k are not the same, walsh (i), walsh (j) and walsh (k) used by PDCH (i), PDCH (j) and PDCH (k) are shown in Table 1b. In this case, only the information about PB and PC is included in WSIC. In Table 1b, the WSI information is transmitted to terminals through an existing broadcast method.

Even when N is larger than 3, the same method as in Table 1b above applies.

In this case, the transmission power of the N-PDCCH uses a size such that the terminal in the worst state among the terminals to receive the PDCH (i) currently being transmitted can successfully receive the N-PDCCH.

Fourth Example

In this case, the CDM is used and the conventional WSI broadcasting method is not used. In other words, Nmax_PDCH is larger than one. Here, it is _assumed that at most one time, only N _{max_PDCH} PDCH (i) and S-PDCCH (i) are used and i = 0, 1, ..., (N _{max_PDCH-} 1).

In this case, the N-PDCCH is transmitted to the terminal at the moment required. In addition, the WSI broadcasting method according to the conventional method is not performed.

In addition, the value of x_N is the number of bits necessary to inform the terminals of which Walsh codes are being used to transmit the N PDCH (i) being transmitted at a certain point in time. As mentioned above, the value of x_N is promised for each N in advance.

Here, the information indicated by the WSIC is about which Walsh codes are used to transmit the N PDCH (i) being transmitted at a particular point in time. Since no separate WSI broadcast method is used, the WSIC information should contain information about the current Walsh code space.

Tables 2a and 2b show the Walsh code lists of the fourth operating example, wherein Walsh_Max = 28 and the current Walsh code space is 25 codes from the highest priority code to the lowest priority code. If it consists of codes.                     

Table 2a shows a case where N is 2, i and j are not the same, and when walsh (i) and walsh (j) used by two PDCH (i) and PDCH (j) are as shown in Table 2a, WSIC contains information about PDs and PEs. In Table 2a, the PE information corresponds to the existing WSI information.

Table 2b shows that when N is 3, i, j, and walsh (i) and walsh (j) used by three PDCH (i), PDCH (j), and PDCH (k) when k is not the same. ), when walsh (k) is shown in Table 2b, WSIC includes information on PF, PG, and PH. In Table 2b, the PH information corresponds to the existing WSI information.

Table 2b above applies the same way when N is greater than three.

Here, the transmission power of the N-PDCCH uses a size such that the terminal in the worst state among the terminals to receive the PDCH (i) currently being transmitted can successfully receive the N-PDCCH.

As described above, the present invention can reduce the waste of available resources by operating the CDM / TDM. In addition, if the CDM / TDM is operated and the Walsh code information is transmitted to the terminals according to the present invention, efficient power usage and safe Walsh code information transmission are ensured in the Walsh code information transmission.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the examples, but should be defined by the claims.

Claims (19)

In a mobile communication system using a time division scheme and a code division scheme, Designating specific numbers for each number of bits required for the cache code information used for data transmission; Adding tail bits for indicating a termination state of encoded data of the input data; Encoding data to which the tail bits are added by varying a coding rate according to the number of bits; Transmitting the encoded data to a control channel for transmitting the data; And transmitting the signal by processing the data. The method of claim 1, further comprising adding an error detection code to the data to be transmitted by changing an initial value of the shifting register according to the number of bits and providing the input data as the input data. The method of claim 1, wherein the specific number is transmitted to a transmitter through a signaling method or a broadcast method. The method of claim 1, wherein the control channel is transmitted to a corresponding receiver when necessary in a time division scheme to provide Walsh code information. The method of claim 1, wherein the control channel is transmitted when Walsh code information by a broadcast method is not provided in a code division scheme to provide Walsh code information. The method according to claim 5, wherein the Walsh code information transmitted through the control channel includes information on the number of Walsh codes used in order from the highest priority code or the number of Walsh codes used in order from the lowest priority code. Packet data transmission method, characterized in that the information. The method of claim 1, wherein the number of finally transmitted bits is made constant per specific unit time. The method of claim 1, wherein the receiving end determines that a current code division scheme is used according to the number of bits. delete delete delete delete delete In the method for transmitting packet data from the network side of the mobile communication system to the terminal, Transmitting packet data to at least two terminals over at least two packet data channels; And And transmitting Walsh code information indicating a Walsh code used in each of the at least two packet data channels to the at least two terminals through a first packet data control channel. The method of claim 14, And transmitting control information related to packet data transmission through the at least two packet data channels to the at least two or more terminals through at least two or more second packet data control channels. The method of claim 14, And the Walsh code information has a variable size according to the number of the at least two packet data channels. The method of claim 16, And the Walsh code information is a value determined according to the number of the at least two packet data channels. The method of claim 14, And the Walsh code information includes an index of a Walsh code corresponding to a boundary of Walsh codes used in each packet data channel on the Walsh code list. The method of claim 15, Wherein the control information comprises an index of the last Walsh code used in the at least two packet data channels on a Walsh code list.

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