KR20040048675A - Method and apparatus for transmitting bursty packet data using orthogonal frequency division multiplexing - Google Patents

Abstract

PURPOSE: A method and an apparatus for transmitting OFDM-based burst packet data are provided to utilize efficiently resources by transmitting directly the corresponding packet data to a base station in a frame having a variable connection packet data transmission position. CONSTITUTION: A resource related to a process for transmitting a preamble to a base station is determined. The preamble is generated according to the determined resource. The generated preamble is transmitted to the base station. A response message and a signal related to a packet data transmission position within a corresponding frame are received from the base station. An analyzing process for the received signals is performed. The corresponding packet data are transmitted to the base station according to the analyzed result.

Description

A burst packet data transmission method and apparatus thereof based on orthogonal frequency division multiplexing {METHOD AND APPARATUS FOR TRANSMITTING BURSTY PACKET DATA USING ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING}

The present invention relates to a burst packet data transmission method and apparatus, and more particularly, to a burst packet data transmission method and apparatus based on orthogonal frequency division multiplexing.

Generally, orthogonal frequency division multiplexing (OFDM) is a type of multicarrier transmission / modulation (MCM) scheme using multiple carriers. In this way, the input data is parallelized and transmitted on each carrier.

This is basically a frequency division multiplexing (FDM) scheme, and since the transmission period in each channel is increased by the number of carriers, frequency selective fading causing inter-symbol interference that may appear in wideband transmission is referred to as frequency non-selective fading. Is approximated.

In this regard, a method for simultaneously transmitting band-limited signals through multichannels without inter-symbol interference (ISI) and inter-channel interference (ICI) has been proposed. An orthogonal multiplexed quadrature amplitude modulation (QAM) method using an oscillator bank of is proposed.

As the OFDM scheme uses suborthogonal subcarriers, the frequency utilization efficiency is increased, and the multipath channel can be easily overcome with a simple frequency domain equalizer having a single tap, and a fast Fourier transform is used. Since it can be implemented at high speed, it is used as a transmission method in wireless communication systems such as digital audio broadcasting (DAB), digital video broadcasting (DVB), IEEE 802.11a, and HIPERLAN / 2.

Typical OFDM-based multiple access schemes include OFDM-TDMA, OFDM-FDMA (hereinafter referred to as OFDMA), and OFDM-CDMA, and each OFDMA allows some users to use some subcarriers out of the total subcarriers without being restricted in time. The allocation of these subcarriers can be dynamically changed according to a user's request.

In detail, the OFDMA scheme allocates different numbers of subcarriers to each user according to a transmission rate required by a user (ie, a terminal), thereby efficiently distributing resources, and unlike the OFDM-TDMA scheme. Since each user does not need to perform a preamble initialization before receiving the data, the transmission efficiency is very high.

In particular, this OFDMA scheme is very suitable for the use of a large number of subcarriers (that is, when the FFT size is large), which is very efficient for a wireless communication system having a large area cell having a relatively large time delay spread.

In addition, when considering packet data transmission in the OFDMA multiple access scheme, first, the entire band is divided into several subcarriers, and then the number of subcarriers is allocated by scheduling at predetermined time intervals (slots) according to a transmission rate required by each user. This is the same principle as allowing multiple users to share and use the entire band, unlike the method of opening each dedicated channel to each user continuously after the previous call setup. Therefore, a method different from the burst packet data transmission method according to the code division multiple access method is required.

Here, as shown in FIG. 1 attached to the code division multiple access scheme, as shown, the random access method in the general code division multiple access system is similar to the RACH message for random access of the reverse (terminal-> base station). Use a separate common channel.

In the OFDMA multiple access scheme, a transmission scheme in which packet data is transmitted is fixed, regardless of whether packet data is transmitted or not, and a random access preamble is transmitted by transmitting random access packet data only at a fixed position. In addition to the time required for transmission and response, there is a transmission delay caused by delaying the transmission to the position where random access packet data can be transmitted. In addition, when configuring the frame of the reverse channel, the shape of the corresponding slot must be changed according to the slot position in the frame.

Related patents in this manner include the right holders, including Kim Jong-ho and four others [Patent name: Apparatus and method for constructing a medium access control frame suitable for a WLAN using an orthogonal frequency division multiplexing method, Application No .: 10-1999-62375]. The present invention provides an apparatus and method for constructing a MAC frame for efficiently processing information transfer between a mobile station and a base station in a wireless LAN system transmitting an IP packet or an ATM cell by OFDM modulation.

Accordingly, there is a need for an efficient resource allocation method and apparatus for a user (terminal) that wants to transmit a message and burst packet data.

The technical problem to be solved by the present invention is to solve this problem, and when the transmission resource is allocated from the base station according to whether the packet data transmission, the packet data directly to the base station in a frame having a variable random access packet data transmission position The present invention provides a method and apparatus for burst packet data transmission based on orthogonal frequency division multiplexing that can reduce time delay due to efficient resource utilization and fast data transmission.

1 is a diagram for explaining a random access method in a general code division multiple access system.

2 is a diagram for describing a detailed structure of a burst packet data transmission apparatus based on orthogonal frequency division multiplexing according to an embodiment of the present invention.

3 is a view for explaining a frame structure having a variable random access packet data transmission position using channel allocation according to an embodiment of the present invention.

4 is a timing related diagram of a forward channel and a reverse channel of a random access method having a variable packet data transmission position according to an embodiment of the present invention.

5 is a flowchart sequentially illustrating a burst packet data transmission method based on orthogonal frequency division multiplexing according to an embodiment of the present invention.

※ Explanation of code for main part of drawing ※

100 terminal 110 receiving unit

120 transmission unit 121 random access transmission / processing unit

121a: preamble response receiver 121b: data transmitter

121c: preamble generator 121d: transmission data selector

122: channel encoder 123: modulator

130: random access processing unit 131: random access data processing unit

132: transmission resource determination unit 200: base station

210: receiving unit 220: random access processing unit

221: data receiving processing unit

222: Preamble reception determination and confirmation signal generation unit

230: transmission unit

Orthogonal frequency division multiplexing based burst packet data transmission method according to an embodiment of the present invention to achieve the above object, orthogonal frequency division multiplexing based burst data transmission method for transmitting subcarriers having orthogonality to the base station at the same time A method comprising: a) determining a resource associated with a preamble transmission to a base station, and then generating a preamble according to the determined resource and transmitting the preamble to the base station; b) analyzing the received signal when receiving a response related to a preamble transmitted from the base station and a signal related to a packet data transmission position within a corresponding frame; And c) transmitting the packet data to the base station in a data frame in which a packet data transmission position is variably configured according to the analyzed result.

In this case, step c) includes configuring all slots identically regardless of positions in the data frame.

In addition, orthogonal frequency division multiplexing based burst packet data transmission apparatus according to another embodiment of the present invention, in the orthogonal frequency division multiplexing based burst packet data transmission apparatus for transmitting subcarriers having orthogonality to each other at the same time, A random access processor configured to determine resources related to preamble transmission to a base station and to perform message processing related to random access to the base station; A preamble generating unit generating a preamble for a random access to the base station; A preamble response receiver configured to analyze the received signal when a response to the preamble and a packet data transmission position in a corresponding frame are received from the base station; and according to the analyzed result, the packet data transmission position is variable And a transmission data selection unit for transmitting the packet data to the base station in the configured data frame.

In addition, according to another aspect of the present invention, a recording medium comprising a burst packet data transmission method based on orthogonal frequency division multiplexing which simultaneously transmits subcarriers having orthogonality to each other to a base station, the method comprising: a) a preamble to a base station; Determining a resource related to the transmission and generating a preamble according to the determined resource and transmitting the preamble to the base station; b) analyzing a response to the preamble transmitted from the base station and analyzing the received signal when a signal related to a packet data transmission position in the frame is received; c) a recording medium storing a program including a function of transmitting the packet data to the base station in a data frame having a variable packet data transmission position according to the analyzed result.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram for describing a detailed structure of a burst packet data transmission apparatus based on orthogonal frequency division multiplexing according to an embodiment of the present invention.

As shown in FIG. 2, a burst packet data transmission apparatus according to an embodiment of the present invention is included in the terminal 100. Such a burst packet data transmission apparatus includes a receiver 110, a transmitter 120, and an arbitrary device. The connection processing unit 130 is included.

In the following embodiments of the present invention, only the functions and operations of the main components included in the burst packet data transmission apparatus will be described for convenience of description.

First, the random access processor 130 includes a random access data processor 131 for processing a message for random access to a corresponding base station and a transmission resource determiner 132 for determining a resource related to preamble transmission for random access. Include.

In addition, the transmitter 120 includes a random access transmitter / processor 121, a channel encoder 122, and a modulator 123, and the receiver 110 includes a demodulator 111 and a channel decoder ( 112).

In this case, the random access transmission / processing unit 121 may include a preamble response receiver 121a confirming a response of the base station to the transmitted preamble, a data transmitter 121b performing random access message transmission, and a preamble for random access preamble transmission. And a transmission data selection unit 121d that selects transmission of a random access preamble and a message according to a response to the preamble of the base station.

Next, the base station 200 includes a receiver 210, a random access processor 220, and a transmitter 230, and the receiver 210 performs a channel decoder 211 and a demodulator 212. The transmitter 230 includes a channel encoder 231 and a modulator 232.

In addition, the random access processing unit 220 receives the random access message transmitted from the terminal 100, and then transmits the random data transmitted from the terminal 100 and the data receiving processing unit 221 to process data received from the receiving unit 210. When the access preamble is received and passed by the demodulator 212 of the receiver 210, after determining what the received preamble is, the preamble reception decision and generation of an acknowledgment signal that transmits the determined information and channel allocation information to the transmitter 230 are generated. Part 222 is included.

Looking at the random access process between the terminal 100 and the base station 200 forming such a structure for a while, the random access processing unit 130 of the terminal 100 generates a random access message, and then transmits the generated random access message. When the random access preamble is transmitted (for example, when to transmit a random access preamble and a transmission channel), the random access transmission / processing unit 121 of the transmission unit 120 first generates a transmission preamble based on the modulation unit 123. Transmit to the base station 200.

Thereafter, when the base station 200 gives a response to the preamble, the receiver 110 of the terminal 100 determines whether to receive the preamble. At this time, if it is determined that the preamble is not properly transmitted, the preamble response is transmitted, and the random access preamble is transmitted again through the preamble generator 121c, the transmission data selector 121d, and the modulator 123.

Subsequently, when it is determined that the preamble is properly transmitted by the reception unit 110, the transmission data selection unit 121d selects a message to be transmitted, and then transmits the corresponding base station through the channel encoder 122 and the modulation unit 123. 200).

As described above, the burst packet data transmission method and apparatus according to an embodiment of the present invention, when a transmission resource is allocated from the base station, forms a frame having a variable random access packet data transmission position and transmits the frame to the base station. Reduce time delays due to resource utilization and fast data transfer.

Here, a frame configuration having a variable random access packet data transmission position will be described in detail with reference to FIG. 3.

3 is a view for explaining a frame structure having a variable random access packet data transmission position using channel allocation according to an embodiment of the present invention.

As shown in FIG. 3, one frame section is set to 20 ms, and one frame is composed of 20 slots (uplink traffic packets), and each slot is a preamble for random access at the beginning of the slot according to the position in the frame. It depends on the slot transmitting RA_P or the slot transmitting CQM_P reporting the channel status.

In this case, a frame having a variable random access packet data transmission position according to an embodiment of the present invention transmits all slots to RA_P or CQM_P (T1), and then transmits a response content for forward transmission (DL response) (T2). And a data traffic transmission time point T3. In this configuration, a terminal state control and a random access packet data transmission time point are variably configured.

Through this, it is possible to prevent a transmission time delay caused by transmitting random access packet data only at a fixed frame position, and to prevent waste of transmission resources when there is no random access message.

In detail, when the terminal 100 randomly transmits a random access preamble selected by the terminal 100, the base station 200 responds to the received preamble with information for synchronization with the base station, received preamble related information, packet data transmission time, The allocation information of the transport channel is also sent down to the forward response channel.

Thereafter, the terminal 100 transmits random access packet data using a portion of the reverse traffic channel according to the allocation related information of the transmission channel received from the base station 200. At this time, the base station 200 receiving the information may know that the packet data already received is random access packet data, not packet data of the active user, through the allocation related information.

That is, the base station allocates resources for random access only when necessary rather than allocating certain resources in advance for random access. This method is called an event-driven method. This is a method that can efficiently use resources and reduce transmission delay. There are various algorithms for allocating resources.

That is, a base station using such an event-driven method selects only one terminal by a resource allocation algorithm even though different random access preambles are transmitted from different terminals at the same channel and at the same time. Efficient resource management is performed by assigning channels to all terminals or unassigning resources to all terminals according to resource conditions.

Here, the timing of the reverse channel and the forward channel according to such random access packet data transmission and reception will be briefly described with reference to the accompanying drawings.

4 is a timing related diagram of a forward channel and a reverse channel of a random access method having a variable packet data transmission position according to an embodiment of the present invention.

As shown, if the preamble determined at the time of transmission of the random access preamble of the reverse channel determined by the random access processing unit 130 of the terminal 100 is transmitted through the random access transmission / processing unit 121 of the terminal 100, a predetermined number Receives the response to the preamble received through the forward channel after the slot delay and synchronization information and channel allocation information through the receiver 110 of the terminal 100, through the preamble response received and transmits the random access of the terminal 100 according to the information The random access packet data is transmitted via the data transmission unit 121b, the transmission data selection unit 121d, the channel encoder 122, and the modulation unit 123 of the processing unit 121.

The overall operation of a burst packet data transmission apparatus based on orthogonal frequency division multiplexing having such characteristics will be described with reference to the accompanying drawings.

5 is a flowchart sequentially illustrating a burst packet data transmission method based on orthogonal frequency division multiplexing according to an embodiment of the present invention.

As shown in the drawing, first, the terminal 100 randomly selects a random access preamble transmission (S501), and then, if the response to the transmitted random access preamble is NACK or no from the corresponding base station (S502), the terminal 100 again. The randomly selected random access preamble is retransmitted (S503).

Subsequently, when channel information (offset, ch num, slot num, etc.) for transmitting ACK and packet data is received from the corresponding base station 200 for the retransmitted preamble (S504), the base station 100 according to the received channel information The packet data is transmitted to the base station (S505), and then the terminal 100 follows a process of the base station responding to the transmitted packet data.

As described above, in the method and apparatus for transmitting burst data based on orthogonal frequency division multiplexing according to an embodiment of the present invention, a position for transmitting random access packet data is variably allocated to a part of a traffic channel in a corresponding frame, thereby Time waste due to efficient resource utilization and transmission time delay can be prevented.

The drawings and detailed description of the invention are merely exemplary of the invention, which are used for the purpose of illustrating the invention only and are not intended to limit the scope of the invention as defined in the claims or in the claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Orthogonal frequency division multiplexing based burst packet data transmission method and apparatus according to the present invention, according to the packet data transmission position received from the base station, the packet data directly in the frame having a variable random access packet data transmission position By transmitting to the base station, as well as efficient resource utilization through this, there is an effect that can reduce the delay time due to fast data transmission.

Claims (8)

In the burst packet data transmission method based on orthogonal frequency division multiplexing which simultaneously transmits subcarriers having orthogonality to the base station, a) determining a resource associated with a preamble transmission to a base station, and then generating a preamble according to the determined resource and transmitting the preamble to the base station; b) analyzing the received signal when receiving a response related to a preamble transmitted from the base station and a signal related to a packet data transmission position within a corresponding frame; And c) transmitting the packet data to the base station in a data frame having a variable packet data transmission position according to the analyzed result; Burst packet data transmission method comprising a. According to claim 1, Step c) is Configuring each slot identically regardless of position within the data frame Burst packet data transmission method comprising a. The method of claim 2, The signal related to the packet data transmission position, A burst packet data transmission method comprising information on a transmission slot and transmission subchannels. According to claim 1, The response related signal to the preamble, Burst packet data transmission method characterized in that the variable is received in accordance with the resource situation. The method of claim 3, wherein The response related signal to the preamble, And a transmission position of random access packet data determined by the base station. An orthogonal frequency division multiplexing based burst packet data transmission apparatus for simultaneously transmitting subcarriers having orthogonality to a base station, A random access processor configured to determine resources related to preamble transmission to a base station and to perform message processing related to random access to the base station; A preamble generating unit generating a preamble for a random access to the base station; A preamble response receiver configured to analyze the received signal when a response to the preamble and a packet data transmission position in the frame are received from the base station; And According to the analysis result, the transmission data selection unit for transmitting the packet data to the base station in a data frame having a variable packet data transmission position is configured Burst packet data transmission apparatus comprising a. The method of claim 6, And each slot in the data frame including the selected random access packet data is identically configured regardless of position. A recording medium comprising a burst packet data transmission method based on orthogonal frequency division multiplexing for simultaneously transmitting subcarriers having mutual orthogonality to a base station, a) determining a resource associated with a preamble transmission to a base station, and then generating a preamble according to the determined resource and transmitting the preamble to the base station; b) analyzing a response to the preamble transmitted from the base station and analyzing the received signal when a signal related to a packet data transmission position in the frame is received; c) a function of transmitting the packet data to the base station in a data frame having a variable packet data transmission position according to the analyzed result The recording medium in which the program is stored.