KR100628310B1 - Packet structure for ultra wide band communication, and apparatus and method for sending/receiving the packet - Google Patents

Abstract

The packet structure of the present invention is for ultra-wideband communication, and includes a PLCP preamble and a frame payload. The PLCP preamble consists of a preamble, a sync word, and a channel estimation sequence. Among the PLCP preambles, the channel estimation sequence and frame payload are composed of OFDM modulated symbols, and the PLCP preamble and syncword are symbols modulated by a modulation scheme other than OFDM modulation, such as BPSK modulation, QPSK modulation, DBPSK modulation, or DQPSK modulation. It consists of.

Description

Packet structure for ultra wideband communication and a transceiver and method using the same {Packet structure for ultra wide band communication, and apparatus and method for sending / receiving the packet}

1 is a block diagram showing a transmission and reception apparatus for a conventional ultra-wideband communication.

Figure 2 is a block diagram showing a transceiver for ultra-wideband communication employing a conventional packet structure.

3 is a diagram illustrating a conventional packet structure employed in the ultra wideband communication transceiver of FIG. 2.

FIG. 4 is a diagram illustrating the PLCP preamble in detail in the packet structure of FIG. 3.

5 is a diagram illustrating a packet structure for ultra-wideband communication according to the present invention.

FIG. 6 is a diagram illustrating an example of a preamble format of the packet structure of FIG. 5.

FIG. 7 is a block diagram illustrating an ultra wideband communication transceiver employing the packet structure of FIG. 5.

The present invention relates to a packet structure for ultra-wideband communication, and a transmission and reception apparatus and method employing the same.

Recently, Ultra Wide Band (UWB) wireless technology is very promising in the field of wireless communication, imaging, and sensor as the wireless transmission performance and unique location awareness ability of the ultra-high speed multimedia data of hundreds of Mbps to 1 Gbps are highlighted. It is attracting much attention as a technology. Conventional ultra-wideband radio technology utilizes pulse waves with very short widths of several tens of picoseconds to several nanoseconds instead of carrier-free forms of carrier waves. Was. Recently, carrier-based UWB technology has been developed to control the spectral form of an ultra-wideband signal, i.e., bandwidth and center frequency.

That is, since 2002, the Institute of Electrical and Electronics Engineers (IEEE) has enacted an international standard called IEEE 802.15.3a for the 500Mbps-class physical layer for high-speed wireless personal area networks (WPANs). Various ultra-wideband communication technologies have been proposed. Compared to the conventional ultra-wideband technology based on a carrier-free pulse wave transmission method, a technique that is recently developed is a method of using a carrier to more closely manage the signal spectrum. Direct Sequence Code Division Multiple Access (DS-CDMA) and multi-band frequency hopping Orthogonal Frequency Division Multiplexing (FH-OFDM), especially for high-speed wireless personal area networks. Frequency Division Multiplexing) is mainly used.

1 is a block diagram showing a transmission and reception apparatus for a conventional ultra-wideband communication.

Referring to FIG. 1, a transceiver for ultra-wideband communication includes a radio controller and a media access controller (MAC) 102 connected to a host or a peripheral device, and an encoder / modulator 106 constituting a transmission line. And an ultra-wideband pulse generator 108, an ultra-wideband receiver and correlator 114 and a decoder / demodulator / synchronizer 116 constituting the reception line, and a switch for switching the transmission line and the reception line. Or a duplexer 110 and a clock / timing generator 104.

2 is a block diagram showing a conventional ultra wideband communication transceiver using the FH-OFDM scheme.

Referring to FIG. 2, first, a transmission line includes a scrambler 202 for mixing input data, a channel encoder 204 for encoding mixed data, and a puncturer for adjusting a data rate. (206), a bit interleaver (208) for changing the data array, a modulator (210) for performing modulation to convert data in bits into symbols, and an inverse fast fourier (IFFT) for performing OFDM modulation. Transform 212, a digital-to-analog converter (DAC) 214 for converting a signal from digital to analog form, and a multiplier 216 for multiplying the input signal with a carrier signal are sequentially arranged.

Next, the reception line includes a low noise amplifier (LNA) 226 for low noise amplifying the received signal, multipliers 228 and 230 for multiplying the signals separated into I and Q signals and a carrier signal, respectively, Low pass filters (LPFs) 232 and 234, VGAs 236 and 238 and analog-to-digital converters (ADCs) 240 and 242 that filter the I and Q signals and change them from analog form to digital form; Fast Fourier Transform (FFT) 244 for demodulation, FEQ 246 for signal distortion compensation, de-interleaver 248 for reconstructing the data array, and Vitaby decoder for decoding the channel (Viterbi decoder) 250, and a de-scrambler 252 for restoring the mixed data again are sequentially arranged. Although not shown in the figure, a demodulator (not shown) is disposed between the FEQ 246 and the deinterleaver 248 to convert a signal in a symbol unit into a signal in a bit unit.

In addition, a local oscillator (LO) generating a time / frequency code 220 for generating time / frequency and an oscillation signal corresponding to the time / frequency generated by the time / frequency code 220, that is, a carrier signal. 218 is disposed in common in the transmission line and the reception line. The carrier signal generated from the local oscillator 218 is input to the multiplier 216 of the transmission line or to the multipliers 228 and 230 of the receiving line.

3 is a diagram illustrating a conventional packet structure employed in the ultra wideband communication transceiver of FIG. 2. FIG. 4 is a diagram illustrating the PLCP preamble in detail in the packet structure of FIG. 3.

First, referring to FIG. 3, a conventional packet includes a PLCP preamble 310, a PHY header 320, a MAC header 330, and an HCS. Check Sequence (340), Tail Bits (350), Frame Payload (360), Frame Check Sequence (FCS) 370, Tail Bits 380, and Pad Bits 390 has a structure that is sequentially arranged in the transmission order. The PHY header 320 includes a 3-bit RATE 321 representing data rate information, an extra 1-bit Reserved 322, a 12-bit LENGTH 323 representing frame length information, and The 2-bit Scrambler Init 324 indicating the scramble method information is sequentially arranged.

Referring next to FIG. 4, the PLCP preamble 310 of FIG. 3 further includes a packet sync sequence 311, a frame sync sequence 312, and a channel estimation sequence. Est Sequence) has a structure in which 313 is sequentially arranged. The packet synchronization sequence 311 is composed of 21 OFDM symbols 311-0, 311-1, ..., 311-20, and the frame synchronization sequence 312 is composed of three OFDM symbols 312-1, 312-2, 312-3, and the channel estimation sequence 313 consists of six OFDM symbols 313-0, 313-1, ..., 313-5.

However, in the FH-OFDM ultra-wideband transmission scheme in which all baseband packets are OFDM-modulated and transmitted and received, the PLCP preamble is long and has a large overhead. As such, a large overhead causes a decrease in the actual transmission speed, and causes a problem of relatively long packet acquisition and synchronization acquisition time.

 It is an object of the present invention to provide a packet structure for ultra-wideband communication that reduces overhead and provides fast synchronization and improved transmission speed.

Another technical problem to be solved by the present invention is to provide a transmission / reception apparatus employing the packet structure.

Another object of the present invention is to provide a transmission and reception method employing the packet structure.

In order to achieve the above technical problem, the packet structure for ultra-wideband communication according to the present invention, in the packet structure for ultra-wideband communication, a PLCP preamble and a frame in which the preamble, syncword and channel estimation sequences are sequentially arranged And a payload, wherein the channel estimation sequence and the frame payload consist of OFDM modulated symbols, and the preamble and syncword consist of symbols modulated by a modulation scheme other than OFDM modulation.

The preamble and syncword may include at least one of a binary phase shift keying (BPSK) symbol, a quadrature phase shift keying (QPSK) symbol, a differential binary phase shift keying (DBPSK) symbol, and a differential quadrature phase shift keying (DQPSK) symbol. It is preferable that it consists of.

It is preferable to further include a PHY header, MAC header, HCS and tail bits arranged sequentially between the channel estimation sequence and the frame payload and FCS, tail bits, and pad bits arranged sequentially after the frame payload.

The preamble includes information for detecting the start timing of a symbol and at the same time confirming the presence or absence of a packet, the syncword includes information for identifying a start point of a header, and the channel estimation sequence indicates a channel state. It is desirable to include information that can predict and compensate for channel distortion.

In order to achieve the above technical problem, a transceiver according to the present invention is a transceiver that employs a packet structure including a PLCP preamble and a frame payload in which a preamble, a sync word, and a channel estimation sequence are sequentially arranged. A modulator configured to perform modulation on the preamble and syncword constituting input data; An IFFT for performing OFDM modulation by the channel estimation sequence and the frame payload; A multiplier that multiplies a pulse signal by an output from the modulator and a carrier signal by an output from the IFFT; And a pulse generator for generating the pulse signal and the carrier signal and supplying the multiplier to the multiplier.

In the present invention, it is preferable to further include a packet detector for detecting the preamble and the sync word transmitted without a carrier signal of the received signal.

In order to achieve the above another technical problem, a transmission and reception method according to the present invention, a transmission and reception method employing a packet structure including a PLCP preamble and a frame payload is configured by sequentially preamble, syncword and channel estimation sequence Performing modulation other than OFDM modulation on the preamble and syncword; Performing OFDM modulation on the channel estimation sequence and frame payload; Multiplying a pulse signal by the preamble and sync word in which modulation other than the OFDM modulation is performed; Multiplying a carrier signal by the OFDM modulated channel estimation sequence and frame payload; And transmitting the preamble and sync word multiplied by the pulse signal and the channel estimation sequence and frame payload multiplied by the carrier signal through an antenna.

In the present invention, detecting and demodulating the preamble and the sync word of the signal received through the antenna; And OFDM demodulating the channel estimation sequence and the frame payload among the signals received through the antenna.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, embodiments of the present invention may be modified in many different forms, and the scope of the present invention should not be construed as being limited by the embodiments described below.

5 is a diagram illustrating a packet structure for ultra-wideband communication according to the present invention. FIG. 6 is a diagram illustrating an example of a preamble format of the packet structure of FIG. 5.

Referring to FIG. 5, the packet structure for ultra-wideband communication according to the present invention includes a PLCP preamble 510 in which a preamble 511, a syncword 512, and a channel estimation sequence 513 are sequentially arranged. . This PLCP preamble 510 is followed by a PHY header 520, MAC header 530, HCS 540, tail bits 550, frame payload 560, FCS 570, tail bits 580 and pads. Bits 590 are arranged sequentially. Here, the preamble 511 and the syncword 512 constituting the PLCP preamble 510 are composed of symbols that have undergone a modulation scheme other than the OFDM modulation scheme. For example, it may be composed of a binary phase shift keying (BPSK) symbol, a quadrature phase shift keying (QPSK) symbol, a differential binary phase shift keying (DBPSK) symbol, or a differential quadrature phase shift keying (DQPSK) symbol.

The preamble 511 constituting the PLCP preamble 510 includes information for detecting the start timing of a symbol and at the same time confirming the presence or absence of a packet. As shown in FIG. 6, the preamble 511 may include nine BPSK symbols 511-1,..., And 511-9. Each BPSK symbol 511-1, ..., 511-9 consists of 8-bit data, such as data such as "00001111". The syncword 512 includes information that allows the starting point of the header arranged later to be known. As shown in FIG. 6, the sync word 512 can be composed of one BPSK symbol 512-1. The BPSK symbol 512-1 is 16-bit data, for example, "0000001001110101". Consists of data. The channel estimation sequence 513 includes information for predicting the channel state by comparing the state before the channel pass and the state after the channel pass, and compensating for the channel distortion. As shown in FIG. 6, the sync word 513 may be configured of six OFDM symbols 513-1, 513-2, 513-3, ..., 513-6.

FIG. 7 is a block diagram illustrating an ultra wideband communication transceiver employing the packet structure of FIG. 5.

Referring to FIG. 7, an apparatus for transmitting / receiving ultra-wideband communication according to the present invention includes a radio controller and a MAC (Media Access) for transmitting input data to a transmission line or output data from a reception line through data transmission with a host or a peripheral device. Controller 702. A transmission line for processing input data from the radio controller and the MAC 702 for transmission through the antenna 726 includes a scrambler 704, a channel encoder 706, a puncturer 708, Bit interleaver 710, modulator 712, pulse shaper 714, IFFT 716, DAC 718, and multiplier 720. Packets transmitted through the transmission line are transmitted through the switch / filter 724 and the antenna 726. Packets input through the antenna 726 and the switch / filter 724 are low noise amplifier (LNA) 728, LPF 734, 736, VGA 738, 740, ADC 742, 744, packet detector / And a timing synchronizer 746, an FFT 748, a de-interleaver 750, a Viterbi decoder 754, and a de-scrambler 756. The output data processed through such a reception line is transmitted to a host or a peripheral device through the radio controller and the MAC 702. In addition, a multimode / multiband pulse generator 722 for generating pulses for supplying the transmission line and the reception line is included.

Specifically, first, in the transmission line, the scrambler 704 mixes and outputs input data transmitted from the radio controller and the MAC 702. Information about the hybridization scheme is stored in the PHY header (520 of FIG. 5) in the packet structure. The channel encoder 706 encodes and outputs a channel of data mixed by the scrambler 704. The puncturer 708 adjusts the data rate of data input from the channel encoder 706 and then outputs the adjusted data rate. The bit interleaver 710 changes the arrangement order of the data whose data rate is adjusted by the puncturer 708 and outputs it.

The modulator 712 modulates data whose arrangement order is changed by the bit interleaver 710, and converts the data in units of bits into symbols. Modulation methods performed by the modulator 712 include BPSK modulation, QPSK modulation, DBPSK modulation, or DQPSK modulation. Accordingly, the modulator 712 performs modulation on the preamble 511 of FIG. 5 and the syncword 512 of FIG. 5 in the packet structure. The pulsesipper 714 smoothly filters the shape of the preamble (511 in FIG. 5) and syncword (512 in FIG. 5) in the packet structure modulated by BPSK modulation, QPSK modulation, DBPSK modulation or DQPSK modulation by the modulator 712. Input to the multiplier 720.

IFFT 716 is the channel estimation sequence of the remainder of the packet structure, i.e., the preamble (510 of FIG. 5), except for the preamble (511 in FIG. 5) and syncword (512 in FIG. 5) transmitted to pulsesipper 714. (513 in FIG. 5), PHY header (520 in FIG. 5), MAC header (530 in FIG. 5), HCS (540 in FIG. 5), tail bit (550 in FIG. 5), frame payload (560 in FIG. 5) ), OFDM modulation is performed on the FCS (570 in FIG. 5), tail bits (580 in FIG. 5), and pad bits (590 in FIG. 5). In this step, a pilot is inserted, and a guard internal to prevent signal distortion caused by signal delay due to cyclic prefix (CP) and multipath for facilitating reception at the receiving end. (GD; Guard Internal) is added. The DAC 718 converts the OFDM modulated symbols by the IFFT 716 from digital form to analog form and outputs them to the multiplier 720.

The multiplier 720 multiplies the preamble (511 of FIG. 5) and the sync word (512 of FIG. 5) input through the pulsesipper 714 with the pulse signal input from the multimode / multiband pulse generator 722. Output it. This pulse signal consists of a pulse wave having a very short width compared with the carrier signal. The multi-mode / multiband pulse generator 722 generates pulse signals of a predetermined frequency under the control of the radio controller and the MAC 702. The multiplier 720 also includes an OFDM modulated packet structure input through the IFFT 716 and the DAC 718, that is, a channel estimation sequence (513 in FIG. 5) and a PHY header (FIG. 5) of the preamble (510 in FIG. 5). 520), MAC header (530 of FIG. 5), HCS (540 of FIG. 5), tailbit (550 of FIG. 5), frame payload (560 of FIG. 5), FCS (570 of FIG. 5), tailbit (580 in FIG. 5) and the pad bit (590 in FIG. 5) are output after multiplying with the carrier signal input from the multi-mode / multiband pulse generator 722. As such, the packet structure multiplied by the carrier signal by the multiplier 720 is transmitted through the antenna 726 via the switch / filter 724.

Next, in the receiving line, the LNA 728 low noise amplifies and outputs a packet structure signal received by the antenna 726 and input through the switch / filter 724. The multipliers 730 and 732 multiply the signals separated into I and Q signals by the carrier signal, respectively, and output the multiplied signals. The LPFs 734 and 736, the VGAs 738 and 740, and the ADCs 743 and 744 respectively filter the I and Q signals multiplied with the carrier signal and output the analog and digital forms. This output signal is simultaneously input to the packet detector / timing synchronizer 746 and the FFT 748. The packet detector / timing synchronizer 746 detects a preamble (511 in FIG. 5) and a syncword (512 in FIG. 5) transmitted without a carrier signal among the input packet structure, and inputs it to the FFT 748. An auto-correlation technique can be used as a method. In addition, it performs a function of synchronizing the timing of the packet structure. The FFT 748 performs OFDM demodulation on the packet structure input from the ADCs 742 and 744. Signal synchronization is achieved at this stage, and typically the cyclic prefix (CP) is also removed. The FEQ 750 compensates for the distortion of the signal input from the FFT 748 and outputs it. Typically the pilot is also removed at this stage. Thereafter, although demodulation is performed on the signal although not shown in the drawing, the array of data constituting the demodulated signal in the deinterleaver 752 is restored to its original form and output. The Viterbi decoder 754 decodes the channel of the signal input from the deinterleaver 752. The descrambler 756 restores the data of the signal transmitted from the Viterbi decoder 754 back to the state before mixing to generate output data. This output data is sent to the host or peripheral via the radio controller and MAC 702.

As described so far, according to the packet structure for the ultra-wideband communication according to the present invention, and a transmitting and receiving device and method employing the same, different modulation and pulse forming methods are applied to the preamble, the sync word, and the payload. It can provide an improved transmission rate due to the reduced packet overhead in the packet structure. In addition, it provides the advantage of reducing the packet acquisition and synchronization acquisition time than the conventional multi-band impulse method.                     

Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art within the technical spirit of the present invention. Do.

Claims (8)

In the packet structure for ultra-wideband communication, A preamble, a syncword and a channel estimation sequence comprising a PLCP preamble and a frame payload sequentially arranged, wherein the channel estimation sequence and the frame payload are composed of OFDM modulated symbols, and the preamble and syncword are OFDM modulation Packet structure, characterized in that consisting of symbols modulated by a modulation scheme other than. The method of claim 1, The preamble and syncword may include at least one of a binary phase shift keying (BPSK) symbol, a quadrature phase shift keying (QPSK) symbol, a differential binary phase shift keying (DBPSK) symbol, and a differential quadrature phase shift keying (DQPSK) symbol. Packet structure, characterized in that consisting of. The method of claim 1, And a PHY header, MAC header, HCS and tail bits sequentially arranged between the channel estimation sequence and the frame payload and FCS, tail bits, and pad bits sequentially arranged after the frame payload. Packet structure. The method of claim 1, The preamble includes information for detecting the start timing of a symbol and at the same time confirming the presence or absence of a packet, the syncword includes information for identifying a start point of a header, and the channel estimation sequence indicates a channel state. A packet structure comprising information for predicting and compensating for channel distortion. A transceiver for adopting a packet structure including a PLCP preamble and a frame payload in which a preamble, a sync word, and a channel estimation sequence are sequentially arranged, A modulator for modulating the preamble and syncword constituting input data; An IFFT for performing OFDM modulation by the channel estimation sequence and the frame payload; A multiplier that multiplies a pulse signal by an output from the modulator and a carrier signal by an output from the IFFT; And And a pulse generator for generating the pulse signal and the carrier signal and supplying the multiplier to the multiplier. The method of claim 5, And a packet detector for detecting the preamble and the sync word transmitted without a carrier signal among the received signals. A transmission / reception method employing a packet structure including a PLCP preamble and a frame payload in which a preamble, a sync word, and a channel estimation sequence are sequentially arranged, Performing modulation other than OFDM modulation on the preamble and syncword; Performing OFDM modulation on the channel estimation sequence and frame payload; Multiplying a pulse signal by the preamble and sync word in which modulation other than the OFDM modulation is performed; Multiplying a carrier signal by the OFDM modulated channel estimation sequence and frame payload; And And transmitting the preamble and sync word multiplied by the pulse signal and the channel estimation sequence and frame payload multiplied by the carrier signal through an antenna. The method of claim 7, wherein Detecting and demodulating the preamble and sync word among signals received through the antenna; And And OFDM demodulating the channel estimation sequence and the frame payload among the signals received through the antenna.

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