KR20030031317A - Method for transmitting/receiving a packet data in Communication System - Google Patents

Abstract

PURPOSE: A method for transceiving packet data in a communication system is provided to operate CDM/TDM(Code Division Multiplexing/Time Division Multiplexing) and to transmit Walsh code information to terminals, so as to efficiently use power upon transmission of the Walsh code information and stably transmit the Walsh code information. CONSTITUTION: A table for a specific bit, types of control channels for receiving data, and types of packet transmission channels in accordance with types of Walsh codes used in the control type is prepared. Priorities are assigned to Walsh codes for transmitting the data and aligned. Walsh codes necessary for the data transmission are allocated from the aligned Walsh codes. The data are transmitted using the allocated Walsh codes. The specific bit indicates 2 bits. And the control channels types include one of 1, 2 and 4 slot number, wherein the 4 slot number has two types according to an initial state of an error correction code.

Description

Method for transmitting / receiving a packet data in communication system

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

In general, wireless communication systems for packet data transmission use physical channels 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.

1 is a diagram illustrating a configuration and a corresponding relationship between a PDCH and an S-PDCCH.

2 is a diagram illustrating types of S-PDCCH.

As shown in FIGS. 1 and 2, the S-PDCCH has three 'lengths of transmission units'. That is, it has a time length of a transmission unit corresponding to the length of one slot, two slots, or four slots. Here, the slot is the minimum basic unit of the time length of the transmission unit, the time length of the transmission unit of the PDCH and S-PDCCH is a multiple of the slot. And, S-PDCCH is a-type, b as shown in Figure 2, depending on the initial value of the shift-registers constituting the cyclic redundancy check (CRC) encoder and the number of slots of the time length of the transmission unit There are four types: -type, c-type, and d-type. There are two types of S-PDCCHs having 4 slots of time length of a transmission unit, which distinguish different initial values of transition registers constituting the CRC coder.

On the other hand, there are four time lengths of the transmission unit of the PDCH: 1 slot (aa-type), 2 slots (bb-type), 4 slots (cc-type), and 8 slots (dd-type). The type of the corresponding S-PDCCH is determined according to the length of the PDCH.

Therefore, the terminal can know the time length of the transmission unit of the PDCH by identifying the type of the S-PDCCH.

In the prior art, the base station transmits one PDCH and S-PDCCH only for one user at any point in time. That is, packet data for each terminal is transmitted on a different time axis, where the PDCH uses all available resources for the PDCH (here, the codes in the Walsh code space) at that time. 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.

Accordingly, the present invention has been made in view of the above-mentioned problems of the prior art, and is to provide a packet data transmission / reception method for increasing resource utilization efficiency.

In addition, the present invention is to provide a packet data transmission and reception method that is suitable for mixing the TDM scheme and the CDM scheme.

According to an aspect of the present invention for achieving the above object, in a mobile communication system using a time division scheme and a code division scheme, specific bits and a control channel type and a control channel for receiving data are used. Preparing a table for types of packet transport channels according to the type of Walsh code; Prioritizing and sorting Walsh codes for transmission of the data; Allocating the Walsh codes necessary for the data transmission from the sorted Walsh codes; And transmitting the data using the assigned Walsh codes.

1 is a view showing the configuration and correspondence of the PDCH and S-PDCCH according to the prior art.

2 shows types of S-PDCCH according to the prior art;

3 shows types of PDCH according to the prior art;

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

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

6A-6B illustrate the types of PDCH and Walsh codes assigned to each of these types.

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 aforementioned Walsh code, PDCH, and PDCCH are used. Here, the Walsh codes, PDCH, and PDCCHs are not limited to the names, but represent codes or channels having the same function. 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 is a collection of Walsh codes currently available when the base station transmits packet data. The components 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. 4, 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. 4, 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. 5, the base station determines the order of data to be transmitted to each terminal (scheduling), and transmits the data in a time division (TDM) and code division (CDM) scheme. 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.

5 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. 5, 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.

As described above, 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.

The present invention proposes a structure of a new control channel in order to use the CDM / TDM scheme as shown in FIG. 5, names the S-PDCCH (i), and proposes an efficient operation method of the proposed control channel.

The control channel proposed in the present invention includes control information as shown in Table 1 below.

Information bit type of S-PDCCH (i) Number of information bits Encoder packet size 3 ARQ channel identifier 2 Subpacket identifier 2 Slot number indicator (SNI) x_i MAC identifier 6 Total bits = (13 + x_i) bits

The MAC identifier is a binary information bit for identifying terminals. Values other than '000000' are information indicating to which terminal the information of the S-PDCCH being transmitted is transmitted.

The ARQ channel identifier and the sub packet identifier are binary information bits that inform the terminal whether to retransmit information on the PDCH corresponding to the S-PDCCH. Specifically, the ARQ channel identifier tells one terminal (assuming that it can transmit multiple retransmission channels) which retransmission channel among the retransmission channels, and in this retransmission channel the number of subpackets (encoded from one information stream) The symbol is repeated and divided into predetermined sub-packets).

The encoder packet size is a binary information bit indicating the number of data information bits transmitted on the PDCH.

The slot number indicator (SNI) is a binary information bit representing information on the Walsh code used by the PDCH (i) among Walsh code spaces or codes on a code priority list as shown in Table 2 below. to be. In this case, the SNI value is interpreted differently by the terminal according to the i value.

32-bin Walsh codes 31 15 23 7 27 11 19 3 29 13 21 5 25 9 30 14 22 6 26 10 18 2 28 12 20 4 24 8

Table 2 above gives priority to all available Walsh codes (hereinafter, Walsh code space). For example, there are a total of 28 Walsh codes with the possibility of being an element of the Walsh code space. If the codes have identifiers that represent them, then the priority identifiers are listed from top to bottom in the order of highest use.

In transmitting the SNI to the terminals, the SNI is used in the following cases.

First, a case in which TDM / CDM is used, and the case where N _{max_PDCH} is 2 are exemplified. That is, only two PDCH (i) and S-PDCCH (i) are used. In the following, it is assumed that i = 0,1, and only PDCH (0), PDCH (1), S-PDCCH (0) and S-PDCCH (1) are used.

The PDCH (0) has a 1: 1 correspondence with the S-PDCCH (0) and the PDCH (1) with the S-PDCCH (1). That is, the control channel for PDCH (0) is S-PDCCH (0), and the control channel for PDCH (1) is S-PDCCH (1). At this time, it is assumed that the number of bits x_0 and x_1 of the SNI are equal to two.

The S-PDCCH (i) may be used to inform the current Walsh code space. That is, a method of broadcasting Walsh code space information (using a control channel for a broadcast channel) is as follows. To do this, S-PDCCH (0) or S-PDCCH (1) is used in the following manner.

Assuming that the S-PDCCH (0) is used, information bits on the S-PDCCH (0) are set as follows. The MAC identifier is set to '000000' and the subpacket identifier is set to '11'. Then, two bits of the ARQ channel identifier and three bits of the encoder packet size are combined to form a 5-bit WSI, and the x_0 bit of the SNI is used for another purpose.

On the contrary, there is also a method in which the information bits of the ARQ channel identifier and the information bits of the encoder packet size are reserved for other purposes, and the SNI provides Walsh code usage information as proposed in the present invention.

The above method can be used in the same manner even when it is assumed that the S-PDCCH 1 is used.

When the S-PDCCH (i) is used to inform the information of walsh codes used by a specific PDCH (i), first, it is necessary to distribute codes used to transmit PDCH (0) or PDCH (1). It must be premised.

If only PDCH (0) or PDCH (1) is present for a time corresponding to one slot (assuming 1.25 msec hereinafter), Walsh (all) is used to transmit them. And, if PDCH (0) and PDCH (1) exist together for a time corresponding to one slot, they are transmitted using walsh (0) and walsh (1), respectively.

The constituent elements of walsh (0) and walsh (1) divide the constituent elements in the walsh code space as described above. At this time, there may be a variety of ways to divide.

In the following, it is assumed that the elements in the walsh code space are divided into two groups evenly, and the names of the two groups are named walsh_fh and walsh_sh. For example, the components of walsh_fh are N_Walsh (all) / 2 codes from the highest priority code in the code priority table among the codes in the walsh code space, and the components of walsh_sh are the remaining codes in the walsh code space. .

If N_Walsh (all) is odd, the constituent elements of walsh_fh are (N_Walsh (all) + 1) / 2 codes from the highest priority code in the code priority table among the codes in the walsh code space, walsh_sh The constituent elements of are the remaining codes in the Walsh code space. walsh (0) and walsh (1) can be either walsh_fh or walsh_sh depending on the situation.

Meanwhile, the type of S-PDCCH (i) according to the length of time of a transmission unit is as follows.

The type of each S-PDCCH (i) is a-type S-PDCCH (i), b-type S-PDCCH (i), and c-type S according to the time length of a transmission unit as in FIG. There are four kinds of -PDCCH (i) and d-type S-PDCCH (i).

In addition, there are 16 types of PDCH (0) and PDCH (1) according to the time length of the transmission unit, respectively, according to the time length of the transmission unit as shown in FIGS. 6A to 6B (assuming that the same number is distributed. ).

In FIGS. 6A to 6B, walsh (all), walsh_fh, and walsh_sh at the bottom of each PDCH indicate that the types of codes used to transmit PDCH (i) in the corresponding slot interval are walsh (all), walsh_fh, walsh_sh. will be.

For example, af2-type PDCH (0) is a PDCH (0) having a total length of 2 slots, and transmits the PDCH (0) using walsh (all) during the first 1.25msec slot period. It means that PDCH (0) is transmitted by using walsh_fh during a slot period of 1.25 msec length.

Accordingly, the terminal receiving the SNI through the S-PDCCH interprets the type of the S-PDCCH (i) and the type of PDCH (i) through the SNI. That is, the terminal may obtain a packet transmission channel transmitted to the terminal through the above analysis process.

The PDCH (i) corresponds to a possible combination between the S-PDCCH (i) and the SNI. Table 3 is an example of the correspondence between them. Of course, various combinations between them are possible.

Type of S-PDCCH (i) SNI Type of PDCH (i) a-type S-PDCCH (0) 00 af0-type PDCH (0) a-type S-PDCCH (0) 01 af1-type PDCH (0) a-type S-PDCCH (0) 10 af2-type PDCH (0) a-type S-PDCCH (0) 11 af3-type PDCH (0) b-type S-PDCCH (0) 00 bf0-type PDCH (0) b-type S-PDCCH (0) 01 bf1-type PDCH (0) b-type S-PDCCH (0) 10 bf2-type PDCH (0) b-type S-PDCCH (0) 11 bf3-type PDCH (0) c-type S-PDCCH (0) 00 cf0-type PDCH (0) c-type S-PDCCH (0) 01 cf1-type PDCH (0) c-type S-PDCCH (0) 10 cf2-type PDCH (0) c-type S-PDCCH (0) 11 cf3-type PDCH (0) d-type S-PDCCH (0) 00 df0-type PDCH (0) d-type S-PDCCH (0) 01 df1-type PDCH (0) d-type S-PDCCH (0) 10 df2-type PDCH (0) d-type S-PDCCH (0) 11 df3-type PDCH (0) a-type S-PDCCH (0) 00 ah0-type PDCH (0) a-type S-PDCCH (0) 01 ah1-type PDCH (0) a-type S-PDCCH (0) 10 ah2-type PDCH (0) a-type S-PDCCH (0) 11 ah3-type PDCH (0) b-type S-PDCCH (0) 00 bh0-type PDCH (0) b-type S-PDCCH (0) 01 bh1-type PDCH (0) b-type S-PDCCH (0) 10 bh2-type PDCH (0) b-type S-PDCCH (0) 11 bh3-type PDCH (0) c-type S-PDCCH (0) 00 ch0-type PDCH (0) c-type S-PDCCH (0) 01 ch1-type PDCH (0) c-type S-PDCCH (0) 10 ch2-type PDCH (0) c-type S-PDCCH (0) 11 ch3-type PDCH (0) d-type S-PDCCH (0) 00 dh0-type PDCH (0) d-type S-PDCCH (0) 01 dh1-type PDCH (0) d-type S-PDCCH (0) 10 dh2-type PDCH (0) d-type S-PDCCH (0) 11 dh3-type PDCH (0)

The terminal can know the type of the PDCH (i) by interpreting the S-PDCCH (i) and the SNI belonging to the S-PDCCH (i) according to Table 3.

Based on the above methods, the base station transmits S-PDCCH (i) and PDCH (i). The terminal receives the PDCH (i) by interpreting the type of S-PDCCH (i) and the information in Table 1 on the S-PDCCH (i).

The method described in the first operation example may be applied in a similar manner as follows, even when N _{max_PDCH} is greater than two. Here, it is _{assumed that} N _{max_PDCH} PDCH (i) and S-PDCCH (i) are used, i is 0,1, ..., (N _{max_PDCH-} 1).

PDCH (i) has a 1: 1 correspondence with S-PDCCH (i). That is, the control channel for PDCH (i) is S-PDCCH (i). At this time, it is assumed that the number of bits x_0 and x_1 of the SNI are equal to two.

If N _{max_PDCH} is greater than 2, the method of broadcasting the Walsh code space is the same as the first operation example.

However, the distribution scheme of codes used to transmit PDCH (i) is as follows.

If only one PDCH (i) is present for a time corresponding to any one slot (hereinafter assumed to be 1.25 msec), Walsh (all) is used to transmit it. And, if there are two or more PDCH (i) during the time corresponding to one slot, they are transmitted using each walsh (i). The constituent elements of walsh (i) divide the constituent elements in the Walsh code space as described above. At this time, there may be various ways to divide.

Hereinafter, it is _assumed that constituent elements in the Walsh code space are uniformly divided into N _{max_PDCH} groups walsh_0, walsh_1, ..., (walsh_N _{max_PDCH} -1). Each walsh (i) can be any of these.

When N _{max_PDCH} is greater than 2, the types of S-PDCCH (i) according to the time length of a transmission unit are similarly as follows.

The type of each S-PDCCH (i) is a-type S-PDCCH (i), b-type S-PDCCH (i), and c-type S according to the time length of a transmission unit as in FIG. There are four kinds of -PDCCH (i) and d-type S-PDCCH (i). The type of PDCH (i) according to the length of time of a transmission unit makes various kinds by applying FIGS.

Through the type of S-PDCCH (i) and the corresponding SNI, the terminal interprets the type of PDCH (i) transmitted to itself. That is, the scheme of Table 3 is applied to map the PDCH (i) to possible combinations between S-PDCCH (i) and SNI. The terminal can know the type of the corresponding PDCH (i) by analyzing the S-PDCCH (i) and the SNI belonging to the S-DPCCH (i).

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 (6)

In a mobile communication system using a time division scheme and a code division scheme, Preparing a table of specific bits, types of a packet transmission channel according to a type of a control channel for receiving data and a type of Walsh code used by the control channel; Prioritizing and sorting Walsh codes for transmission of the data; Allocating the Walsh codes necessary for the data transmission from the sorted Walsh codes; Transmitting the data using the assigned Walsh codes. 2. The method of claim 1, wherein the specific bits are two bits. The method of claim 1, wherein the control channel types have any one of 1, 2, 4, and slots, and the 4 slots have two types according to an initial state of an error detection code (CRC). Packet data transmission method. 2. The method of claim 1, wherein when the control channel is a broadcast channel, the specific bits are not used to determine the type of the packet transport channel. In a mobile communication system using a time division scheme and a code division scheme, Preparing a table of specific bits, types of a packet transmission channel according to a type of a control channel for receiving data and a type of Walsh code used by the control channel; Identifying specific bits of the received control channel and the type of the received control channel to identify the type of packet transmission channel in the table; Receiving the packet transmission channel of the type according to the Walsh code information already received. 6. The method of claim 5, wherein the specific bits are two bits.