CN101444051A - System and method for wireless communication of uncompressed video having a preamble design - Google Patents

Abstract

A method and system for transmitting uncompressed video information from a sender to a receiver over a wireless channel is described. Uncompressed video information bits are provided at the sender and the video information bits are packetized into one or more packets. A preamble to precede the data in each packet is provided, where the preamble includes a set of short training sequences and a set of long training sequences. Multiple packets are transmitted from the sender to the receiver over a wireless channel. In certain embodiments, the set of short training sequences includes seven short training sequences and the set of long training sequences includes two long training sequences, and the total length of the preamble is five orthogonal frequency-division multiplexing (OFDM) symbols long.

Description

The system and method that is used for the radio communication of uncompressed video with preamble design

Technical field

The present invention relates to the wireless transmission of video information, particularly, relate to the unpressed high-definition video information of transmission on wireless channel.

Background technology

In the wireless HD specification version 0.1 of issue on July 12nd, 2006, preamble sequence has been proposed.This preamble has eight OFDMs (OFDM) symbol lengths.Preceding four OFDM symbols are defined within time domain, and are used to wrap detection, frame synchronization and automatic gain control (AGC) training.Produce time domain sequences from length 255m sequence (from the maximum length phase shift register of PN codes generator), fill up six zero and by 1.5 times of up-samplings.Sequence is the quasi-periodicity with cycle of 382.5 as a result.The thresholding when lengths table 17 of wireless HD standard provides for preceding four symbols of preamble.Four the OFDM symbols in back are defined within frequency domain, and are used for frequency shift (FS) and channel estimating.The table 18 of wireless HD standard provides frequency domain value for back four symbols of preamble.Before being converted to time domain sequences, with the frequency domain value multiplication by constants 1 of symbol 5,6 and 7, with the frequency domain value multiplication by constants-1 of symbol 8.Obtain time-domain sampling by 512 point, inverse fast Fourier transform (IFFT) that adopt corresponding frequency domain value, before first sampling, form 576 sampling symbols by repeated sampling 448-511 (last 64 samplings of IFFT output).Because each OFDM symbol approximately has duration of 230ns, so eight OFDM symbols have the duration of 1.84 μ s.

Summary of the invention

Technical problem

Along with the development of high-quality video, increasing electronic installation (for example, consumer electronics device) utilization may need high definition (HD) video of the bandwidth of thousands of MBPSs (Gbps) to transmit.Like this, when this HD video of transmission between device, conventional transportation method reduces required transmission bandwidth with the HD video compression for the part of its size.Subsequently, the video of compression decompressed be used for consumption.Yet along with to each compression of video data and decompression subsequently, some video informations can be lost and picture quality can reduce.

HDMI (High Definition Multimedia Interface) (HDMI) standard allows to transmit unpressed HD signal via cable between device.Though consumer electronics manufacturer begins to provide the equipment of compatible with HDMI, also not suitable wireless (for example, the radio frequency) technology that can transmit unpressed HD vision signal.When not having enough bandwidth and come some devices of the unpressed HD signal of load to connect, wireless lan (wlan) can run into interference problem with similar technology.

Technical scheme

In one embodiment, have and a kind ofly on wireless channel unpressed video information is sent to the method for receiver from transmitter, this method comprises: provide unpressed video information bits at transmitter; Video information bits is bundled to one or more bags; Provide preamble before the data in each bag, wherein, this preamble comprises one group of short training sequence and group leader's training sequence; And on wireless channel, a plurality of bags are sent to receiver from transmitter.

Be shaped at symbol, on conversion and send before described preamble is inserted in the bag.The total length of preamble is five OFDMs (OFDM) symbol lengths.Every group of short training sequence can be 256 samples, and every group leader's training sequence can be 512 samples.One group of short training sequence comprises seven short training sequences, and group leader's training sequence comprises two long training sequences.One group of short training sequence can comprise the repetition of particular sequence, and last repeating is rotated 180 degree.One group of short training sequence can comprise the repetition of particular sequence, and last repeating is not rotated 180 degree.The protection of length 64 can separate described one group of short training sequence at interval with described group leader's training sequence.The preamble total length is five OFDM symbols, and can comprise the protection interval of the short training sequence of seven length 256, a length 64 and the long training sequence of two length 512.Can use Quadrature Phase Shift Keying (QPSK) signal on frequency domain, to define each short training sequence, can use binary phase shift keying (BPSK) signal on frequency domain, to define each long training sequence.

In another embodiment, there is a kind of system that is used for the radio communication of unpressed high definition video with preamble design, this system comprises: transmitter, be arranged to produce and flow corresponding signal packet with high definition video, wherein, described each signal packet comprises head part and video data part, and wherein, described head part starts from having the preamble of one group of short training sequence and group leader's training sequence; Wireless channel is arranged to the signal packet that sends the unpressed high definition video stream of expression.

Use Quadrature Phase Shift Keying (QPSK) signal on frequency domain, to define each short training sequence, use binary phase shift keying (BPSK) signal on frequency domain, to define each long training sequence.The total length of preamble is five OFDMs (OFDM) symbol lengths.Each short training sequence can be 256 samples, and each long training sequence can be 512 samples.One group of short training sequence can comprise seven short training sequences, and described group leader's training sequence can comprise two long training sequences.One group of short training sequence can comprise the repetition of particular sequence, and last repeating is rotated 180 degree.One group of short training sequence can comprise the repetition of particular sequence, and last repeating is not rotated 180 degree.The protection of length 64 can separate described one group of short training sequence at interval with described group leader's training sequence.The preamble total length is five OFDM symbols, and can comprise the protection interval of the short training sequence of seven length 256, a length 64 and the long training sequence of two length 512.

In another embodiment, have and a kind ofly on wireless channel unpressed video information is sent to the system of receiver from transmitter, this system comprises: the device that unpressed video information bits is provided at transmitter; Video information bits is bundled to the device of one or more bags; The device of preamble is provided before the data in each bag, and wherein, this preamble comprises one group of short training sequence and group leader's training sequence; And the device that on wireless channel, a plurality of bags is sent to receiver from transmitter.

Each short training sequence can be 256 samples, and each long training sequence can be 512 samples.The preamble total length is five OFDM symbols, and can comprise the protection interval of the short training sequence of seven length 256, a length 64 and the long training sequence of two length 512.Can use Quadrature Phase Shift Keying (QPSK) signal on frequency domain, to define each short training sequence, can use binary phase shift keying (BPSK) signal on frequency domain, to define each long training sequence.

Description of drawings

Fig. 1 is the functional block diagram that illustrates according to the exemplary configuration of the wireless network of carrying out unpressed HD video transmission between wireless device of the embodiment of system and method;

Fig. 2 is the functional block diagram that is used for the example communication system of the unpressed HD video of transmission on wireless medium that illustrates according to the embodiment of system and method;

Fig. 3 is the diagrammatic sketch such as the embodiment of the bag that uses in network shown in Fig. 1 and Fig. 2 and system;

Fig. 4 is the diagrammatic sketch such as the embodiment of the preamble design of using in the bag shown in Figure 3;

Fig. 5 is the curve chart that quantizes the example of relevant output that the short length sequences of 256 samples as shown in Figure 4 is shown;

Fig. 6 is a curve chart that quantizes the example of relevant output that illustrates such as the sequence of 383 samples that use in preamble design before;

Fig. 7 is the diagrammatic sketch such as the optional embodiment of the preamble design of using in bag shown in Figure 3;

Fig. 8 is the block diagram such as the embodiment of the transmit chain of the assembly that uses in transmitter shown in Figure 2;

Fig. 9 is the block diagram such as the embodiment of the receiver chain of the assembly that uses in receiver shown in Figure 2.

Embodiment

The detailed description of following specific embodiment provides the various descriptions of specific embodiment of the present invention.Yet the present invention can realize with the multiple diverse ways that is defined by the claims and covers.In this is described, represent the accompanying drawing of identical parts all the time with reference to identical label.

Should not explain the term that in this description, uses, only owing to use this term in conjunction with the detailed description of specific embodiment of the present invention with any restriction or restrictive mode.In addition, embodiments of the invention can comprise several features of novelty, do not have an independent attribute of being responsible for its expectation alone or its to put into practice the present invention described herein in essence in them.

Specific embodiment provides a kind of method and system that unpressed HD video information is sent to receiver on wireless channel from transmitter.Video information is placed in the bag with the head that comprises preamble.Preamble described below is more effective than the preamble of describing before, has more performance aspect correlation, and is easier to implement.

The example implementation of the embodiment of wireless high-definition degree (HD) audio/video (A/V) system now will be described.Fig. 1 is the functional block diagram of carrying out the wireless network 100 of unpressed HD video transmission between A/V device (such as, A/V device telegon and A/V station) that illustrates according to specific embodiment.In another embodiment, one or more devices can be computer (such as, personal computer (PC)).Network 100 comprises: device telegon 112 and a plurality of A/V station 114 (for example, device 1... device N).

Low rate (LR) wireless channel 116 (dotted lines among Fig. 1) are used at A/V station 114, maybe can use two-forty (HR) channel 118 (solid line among Fig. 1) to communicate by letter between any device.Device telegon 112 uses low-rate channel 116 and high-rate wireless channel 118 to communicate by letter with station 114.Each station 114 uses low-rate channel 116 to communicate by letter with other station 114.High speed channel 118 supports to have for example unidirectional unicast transmission of many Gb/s bandwidth on the directional beam that forms foundation by wave beam, to support unpressed HD video transmission.For example, set-top box can be on high speed channel 118 sends to unpressed video HD TV (HDTV).In a particular embodiment, low-rate channel 116 can support throughput for example mostly to be most the transmitted in both directions of 40Mbps.Low-rate channel 116 be mainly used in transmission control frame (such as, confirm (ACK) frame).For example, low-rate channel 116 can send to set-top box from HDTV with confirming.Can directly between two devices, on low-rate channel, send low-rate data equally as the video of audio frequency and compression.Time division duplex (TDD) is applied to high speed channel and low-rate channel.In a particular embodiment, at any time, can not walk abreast and use low-rate channel and high speed channel to be used for transmission.Beam-forming technology can be used to low-rate channel and high speed channel.Low-rate channel also can be supported omni-direction transmissions.

In one embodiment, device telegon 112 is receivers (hereinafter referred to as " receiver 112 ") of video information, and standing 114 is transmitters (hereinafter referred to as " transmitter 114 ") of video information.For example, receiver 112 can be the receiving system such as the video and/or audio of implementing in the HDTV as the family wireless network environment of WLAN type.Transmitter 114 can be the source of unpressed video or audio frequency.The example of transmitter 114 comprises: set-top box, DVD player or video tape recorder, digital camera, field camera etc.

Fig. 2 is the functional block diagram that example communication system 200 is shown.System 200 comprises radio transmitters 202 and wireless receiver 204.Transmitter 202 comprises physics (PHY) layer 206, medium access control (MAC) layer 208 and application layer 210.Similarly, receiver 204 comprises PHY layer 214, MAC layer 216 and application layer 218.The PHY layer provides radio communication via one or more antennas by wireless medium 201 between transmitter 202 and receiver 204.

The application layer 210 of transmitter 202 comprises A/V pretreatment module 211 and audio frequency and video control (AV/C) module 212.A/V pretreatment module 211 can be carried out the preliminary treatment (such as cutting apart of, unpressed video) of audio/video.AV/C module 212 provides the standard method of exchange A/V capacity information.Before connecting beginning, the AV/C module negotiates is with the A/V form that is used, and when finishing the demand of connection, use AV/C order stops to connect.

In transmitter 202, PHY layer 206 comprises and is used for low rate (LR) channel 203 and two-forty (HR) channel 205 of communicating by letter with radio frequency (RF) module 207 with MAC layer 208.In a particular embodiment, MAC layer 208 can comprise the packetization module (not shown).The PHY/MAC layer of transmitter 202 adds PHY and MAC head bag to and by wireless channel 201 bag is sent to receiver 204.

In wireless receiver 204, PHY/MAC layer 214,216 is handled the bag that receives.PHY layer 214 comprises the RF module 213 that is connected to one or more antennas.LR channel 215 is used for communicating by letter with RF module 213 with MAC layer 216 with HR channel 217.The application layer 218 of receiver 204 comprises A/V post-processing module 219 and AV/C module 220.The anti-processing method of module 219 executable modules 211 is for example rebuild unpressed video.AV/C module 220 is operated with complimentary fashion with the AV/C module 212 of transmitter 202.

In a particular embodiment, each bag has the preamble as the part in packet header.In the PHY layer, handle preamble.

With reference to Fig. 3, will the embodiment of bag 300 be described.Bag 300 comprises Physical layer convergence protocol (PLCP) 310 and video data part 330.PLCP 310 comprises preamble 330 and other field.In a particular embodiment, other field comprises high-rate physical layer (HRP) head, MAC head and can be the MAC head expansion of a verification sequence (HCS).In a particular embodiment, video data part 330 comprises Medium Access Control (MAC) Protocol Data Unit (MPDU) data field, cyclic redundancy check (CRC) (CYC) information, tail bit and pad position.

With reference to Fig. 4, preamble 400 embodiment of (such as, preamble 320 shown in Figure 3) will be described.Preamble 400 comprises seven short training sequences 410 and 420, and two long training sequences 440.In a particular embodiment, each short training sequence is that 256 samples (each sample can be a plural number) are grown, and the final nucleotide sequence 420 of short training sequence is rotated 180 degree with end of indicating short sequence and the beginning of growing sequence.Each long training sequence is that 512 samples are long, have short training sequence 410 and 420 and long training sequence 440 between 64 samples protection that is known as Cyclic Prefix (GI) 430 at interval.The total length of preamble 400 is the long (256 * 7+64+512 * 2=2880=576 of five OFDM symbols

×5)。The duration of preamble is 5 * 230ns=1.15 μ s, duration of 1.84 μ s of the preamble known to before being better than.In another embodiment, can use other sample number that is used for short training sequence and/or long training sequence.In another other embodiment, the sample number in the long training sequence is the twice of the sample number in the short training sequence.

Zero Quadrature Phase Shift Keying (QPSK) signal that use has insertion defines long 256 short training sequence 410 on frequency domain.In QPSK, two data bit are mapped to a symbol (plural number).The QPSK signal be placed on tone (tone) [178:2:-22:2:178] (that is, and tone index-178,176 ... ,-2,2,4 ..., 178) on, zero is inserted on other tone.Each tone is represented small band or subcarrier (such as, the bandwidth between from 59GHz to 61GHz).In a particular embodiment, 512 wave bands have been used.Obtain the QPSK signal the time domain peak value is minimized to average ratio and dynamic range (peak value is to valley) ratio by random search,, and improve acquisition performance so that signal can send.In one embodiment, random search produces following short training sequence:

STF _-178，178＝sqrt(1/2)

{1+i，0，1+i，0，-1-i，0，1-i，0，1+i，0，-1+i，0，-1-i，0，-1+i，0，1+i，0，1-i，0，1-i，0，-1-i，0，-1-

i，0，1+i，0，-1-i，0，-1-i，0，1-i，0，-1+i，0，1+i，0，1+i，0，-1+i，0，-1-i，0，-1+i，0，1-i，0，1+i，0，-1-i，0，1-i，0，-1+i，0，-1-i，0，-

1+i，0，1-i，0，-1+i，0，-1-i，0，-1-i，0，1+i，0，-1-i，0，1+i，0，-1+i，0，-1+i，0，1+i，0，-1+i，0，-1-i，0，-1-i，0，-1-i，0，1+i，0，1-i，0，-

1+i，0，1-i，0，1+i，0，1-i，0，-1+i，0，-1+i，0，-1-i，0，-1-i，0，-1-i，0，-1-i，0，1-i，0，-1+i，0，1+i，0，-1+i，0，1+i，0，-1+i，0，1-i，0，-

-1+i，0，1+i，0，1-i，0，1+i，0，-1-i，0，1-i，0，1-i，0，1-i，0，-1+i，0，1-i，0，1-i，0，1-i，0，-1-i，0，1+i，0，1-i，0，1+i，0，1+i，0，1-i，0，-

-1+i，0，-1+i，0，1-i，0，1-i，0，-1-i，0，1-i，0，-1-i，0，-1-i，0，0，0，-1+i，0，1+i，0，1-i，0，1-i，0，1-i，0，-1+i，0，1-i，0，1-i，0，-1+i，0，-

-1+i，0，-1-i，0，1+i，0，-1+i，0，1-i，0，-1-i，0，-1-i，0，1+i，0，-1-i，0，1-i，0，1+i，0，1+i，0，-1+i，0，1-i，0，-1-i，0，1-i，0，1+i，0，-1-

-i，0，-1-i，0，1-i，0，1-i，0，-1+i，0，1+i，0，-1-i，0，1-i，0，1-i，0，-1-i，0，-1-i，0，1-i，0，1+i，0，1-i，0，1-i，0，1-i，0，1-i，0，-1-

i，0，1+i，0，1+i，0，-1-i，0，-1-i，0，1-i，0，-1-i，0，-1-i，0，1-i，0，1-i，0，-1+i，0，-1+i，0，-1-i，0，1+i，0，-1-i，0，1+i，0，-1+i，0，1-

-i，0，1-i，0，-1+i，0，1-i，0，-1-i，0，-1+i，0，-1+i，0，1-i，0，-1+i，0，1+i，0，-1+i，0，1+i，0，1-i，0，1-i，0，1+i，0，1-i，0，1+i，0，-1+i，0，-

-1+i，0，1-i，0，-1-i，0，1+i，0，1-i，0，-1+i，0，1+i，0，-1+i，0，-1-i，0，1-i，0，1+i}

The final nucleotide sequence 420 of short training sequence is rotated 180 degree.This causes the reversed peak 520 in relevant output place as shown in Figure 5.Reversed peak 520 can help to determine the beginning of the long sequence of the ending of short sequence of preamble and preamble.

Use binary phase shift keying (BPSK) signal on frequency domain, to produce long 512 long training sequence 440.In BPSK, a data bit is mapped to a symbol (special plural number=real number).Produce the bpsk signal sequence to minimize time domain PAPR by random search.Frequency domain sequence be placed on the OFDM tone and by as give a definition:

LTF _-177，177＝{-1，1，-1，1，-1，1，1，-1，1，-1，-1，-1，1，-1，1，-1，-1，1，

1，-1，-1，1，-1，1，1，-1，-1，-1，-1，1，-1，1，1，-1，-1，1，1，-

1，-1，1，1，1，1，1，1，1，1，1，1，-1，1，-1，-1，1，1，1，1，1，-1，-1，-1，-1，1，-1，-1，1，-1，-1，-1，-1，-1，-1，-1，1，-1，-1，-1，1，1，-1，-

1，1，1，1，-1，-1，1，1，-1，1，1，1，-1，1，1，1，-1，1，1，-1，-1，1，-1，1，-1，-1，1，-1，-1，1，1，1，1，1，-1，-1，-1，-1，-1，-1，1，-1，1-，1，-1，-1，1，-1，1，-1，-

1，1，-1，-1，1，-1，-1，1，1，-1，-1，-1，-1，1，1，-1，1，1，1，1，1，1，1，1，-1，-1，1，-1，1，-1，-1，-1，1，1，-1，-1，1，1，-1，1，1，-1，1，-1，-1，1，-

1，1，-1，1，0，0，0，-1，-1，1，-1，-1，-1，1，1，-1，-1，1，-1，-1，-1，-1，1，-1，1，-1，-1，-1，1，-1，1，-1，-1，-1，-1，1，-1，-1，-1，1，-1，-1，1，-

1，1，-1，-1，-1，1，1，-1，1，1，1，-1，-1，-1，1，-1，1，-1，1，-1，1，1，1，-1，-1，-1，1，1，-1，-1，-1，-1，-1，-1，1，1，1，-1，1，-1，-1，-1，1，-1，1，-

1，1，1，1，1，-1，-1，1，-1，1，-1，-1，-1，-1，-1，1，-1，-1，1，-1，-1，-1，-1，1，1，-1，1，-1，1，1，1，1，-1，1，1，1，1，1，1，-1，-1，1，-

1，1，1，1，1，-1，1，1，1，1，1，1，-1，-1，1，1，1，-1，-1，-1，-1，1，-1，-1，1，1，1，1，-1，1，1，-1，-1，-1，1，1，1，-1，-1，-1，-1，1，1，1，1，-1，-

1，1，1，1，1，1，-1}

The GI430 of 64 samples is Cyclic Prefix of long training sequence 440, is used to handle the intersymbol interference that is caused by channel time delay expansion.

With reference to Fig. 5, description is illustrated 1 curve chart 500 that quantizes relevant output of the short long sequence of 256 samples.The x axle express time of curve chart 500 postpones, and the y axle is represented correlation.Use short sequence 410 (Fig. 4), can find out from curve chart 500 and use 1 short sequence that quantizes to be correlated with to have extraordinary association attributes.Curve chart 500 shows the design of the good sequence with superperformance.Compare with the preamble design before using, correlation peak 510 has approximate 512 the correlation on curve chart 500 that more easily detects.In addition, compare with the preamble design before using, reversed peak 520 has approximate-512 the correlation on curve chart 500 of easier detection.

Preamble 400 (Fig. 4) produces higher efficient and better correlation than preamble design before.Efficient than before preamble design higher be because: than eight the OFDM symbols of the duration that is used for 1.84 μ s in design before, only need to be used for five OFDM symbols of the duration of 1.15 μ s.Because preamble is considered to expense, so it is more efficient to have a shorter preamble.Further advantage is: the design before comparing, crosscorrelation are handled (because by relevant addition) and are produced bigger peak value.Another advantage of preamble 400 is: than preceding four OFDM symbols and back four OFDM symbols of the lengths table shown in the wireless HD specification version 0.1, the definition of short sequence and long sequence is succinct.Therefore, for the implementer, understand the structure of preamble and design corresponding receiver easily.For example, the designs before use preamble 400 ratios use need tone still less.

With reference to Fig. 6, description is illustrated 1 curve chart 600 that quantizes relevant output of the sequence of 383 samples.The x axle express time of curve chart 600 postpones, and the y axle is represented correlation.Curve chart 600 illustrates the relevant output that is used for previous preamble design.Compare with the preamble design shown in Fig. 5 at Fig. 4 with using, correlation peak 610 has approximate 383 the correlation on curve chart 600 that more is difficult to detect and less than the correlation peak 615 of 300 value.

With reference to Fig. 7, will the embodiment (such as, the preamble 320 shown in Fig. 3) of preamble 700 be described.In this design, last short training sequence is rotated 180 degree unlike the sequence among Fig. 4 420.Detect the end of short sequence by preceding 256 samples of the relevant last short sequence and first long training sequence.When not having peak value to be detected by being correlated with, it is used as the end of short training sequence.

Preamble 700 comprises seven short training sequences 710 and two long training sequences 740.In a particular embodiment, each short training sequence is that 256 samples are long.Each long training sequence is that 512 samples are long, has 64 sample protection interval (GI) 730 between short training sequence 710 and long training sequence 740.The total length of preamble 700 is five OFDM symbols long (256 * 7+64+512 * 2=2880=576 * 5).

With reference to Fig. 8, with describing module, subsystem or device (such as, in PHY piece 206 (Fig. 2), use) transmit chain 800.Be appreciated that and use hardware, software or the combination of the two to realize these modules, subsystem or device.Have video data (such as, from video player or other device) video sequence 810 be transfused to scrambler 815.Scrambler 815 transposing or inverted signal, or coded data so that data in the receiver of unequipped corresponding descrambler, can't be identified.Realize scrambling by some important component of component being added primary signal into or changing primary signal, thereby be difficult to extract primary signal.The latter's example comprises and removes or change horizontal or vertical lock-out pulse in the vision signal.

Forward error correction (FEC) subsystem 820 receives output and error protection is provided during wireless data transmission from scrambler.FEC subsystem 820 adds redundant data to the video data of the scrambling that is input to subsystem.Redundant data allows receiver to detect and rights a wrong, needn't be to transmitter request additional data.Add redundant data to video data, FEC subsystem 820 can use the error coding encoder (such as, Reed-Solomon (RS) encoder and convolution code (CC) encoder).In another embodiment, FEC subsystem 820 can use various other encoders, includes but not limited to: dagger-axe Lay encoder, hamming code device and Bose-Chaudhuri-Hocquenghem Code device.

The output of FEC subsystem 820 is sent out the interleaver 825 that puts in place.Position interleaver 825 rearranges from the sequence of the data bit of FEC820 reception.Interleaver 825 pairs of video datas that send on wireless medium in position provide further error protection.The output of position interleaver 825 is sent to mapper 830.Mapper 830 is mapped to plural number (IQ) symbol (frequency domain data) with data bit.Complex symbol is used for above-mentioned wireless transmission modulated carrier.Mapper 830 can use various modulation systems, includes but not limited to: binary phase shift keying (BPSK), Quadrature Phase Shift Keying (QPSK) and quadrature amplitude modulation (QAM).In one embodiment, mapper 830 is QAM mapper (for example, 16-QAM mapper or 64-QAM mappers).QAM is the modulation system of coming translation data by the amplitude of modulating two carrier waves.These two normally sinusoidal waveforms are offset 90 phase place each other, are called as quadrature carrier." QAM " preceding numeral 16 or 64 expression mappers can the mapping (enum) data hyte the total quantity of symbol.For example, the 16-QAM mapper is converted to 2 with 4 bit data ⁴=16 symbols.Typically, for the QAM mapper, use planisphere (constellation) to represent these symbols.

The output of mapper 830 is sent to the symbol interleaver 835 that rearranges from the sequence of the complex symbol of mapper output.The symbol interleaver 835 that illustrates is positioned at after the mapper 830.In other embodiments, the interleaver place, position that symbol interleaver 835 can be between FEC and mapper 830.In these embodiments, the symbol interleaver sequence changes predetermined figure place as symbols.For example, at the QAM mapper four data bit are mapped among the embodiment of complex symbol, symbol interleaver is arranged to the group of four data bit that interweave.

Embodiment after symbol interleaver 835 is arranged in mapper 830, symbol interleaver rearranges from the sequence of the symbol of mapper 830 outputs.In one embodiment, symbol interleaver 835 can comprise and uses fixing put in order at random and according to the random interleaver of the interleaved symbol that puts in order.For example, random interleaver can use the Radix-2FF operation.In other embodiments, symbol interleaver 835 can comprise block interleaver.Block interleaver accept a group code and do not repeat or the omission group in the situation of any one symbol under rearrange them.The fixed amount of the symbol in given interleaver in every group.Interleaver is independent of its operation on other group code in the operation on the group code.

The output of symbol interleaver 835 is sent to invert fast fourier transformation (IFFT) module 840.IFFT840 will change corresponding time domain data from the frequency domain data of error detection module, mapping block and interleaving block into.IFFT module 840 will represent that a large amount of complex symbols of the signal in the frequency domain are converted to the time-domain signal of equivalence.IFFT module 840 is used to also guarantee that the carrier signal that produces is a quadrature.The output of IFFT module 840 is sent to cyclic prefix adder 845 to reduce the complexity of receiver.Cyclic prefix adder 845 also can be called as the protection interval adder.Cyclic prefix adder 845 is added cyclic prefix interval (or protection at interval) to the front end of the block of IFFT processing.The duration of this cyclic prefix interval can be 1/32,1/16,1/8 or 1/4 of the primary signal piece duration.

On this aspect of transmit chain 800, preamble 850 (such as, preamble 400 (Fig. 4)) as a part of 310 and prior to the block that IFFT handles be inserted into bag (such as, wrap 300 (Fig. 3)) in.Preamble 850 is selected by the designer of system 200 (such as described before) and by standardization, thereby makes all devices of system understand preamble 850.

Symbol shaping module 855 will be from the bag signal interpolation and the low-pass filtering of IFFT module 840, cyclic prefix adder 845 and preamble 850 generations.The output of symbol shaping module 855 is complex baseband of the output signal of IFFT module 840.Up converter 860 is intermediate frequency (IF) with the be shaped output up conversion of module 855 of symbol.The signal up conversion that up converter 860 also is arranged to up conversion is radio frequency (RF).One group of transmitting antenna 865 will send to receiver from the signal of up converter 860 outputs on wireless medium (such as, wireless channel 201 (Fig. 2)).Transmitting antenna 865 can comprise any antenna system or the module that is applicable to the unpressed HD vision signal of wireless transmission.

With reference to Fig. 9, with describing module, subsystem or device (such as, in PHY piece 214 (Fig. 2), use) receiver chain 900.The anti-processing of the transmit chain 800 of receiver chain module execution graph 8.Receiver 900 receives RF signals via wireless channel 201 (Fig. 2) from the transmitting antenna 865 of transmitter 800 at reception antenna 910.Downconverter 915 is the frequency that is suitable for handling with RF signal down conversion.Then, analog to digital converter (not shown) is a digital signal with signal transformation.Preamble finder 920 is located the preamble portion of digital signal subsequently.In a particular embodiment, preamble finder 920 comprises the correlator that can operate the short training sequence of preamble (Fig. 4 and Fig. 7) and unwraps the beginning search algorithm.After preamble was by search engine 920 identifications, the preamble portion of current demand signal bag was sent to channel estimating, synchronous and timing recovery assembly 925, will be in following description.Cyclic prefix remover 930 removes the Cyclic Prefix of preamble from signal.In a particular embodiment, also have the Cyclic Prefix of the video data part that is used to wrap, thereby all have the intersymbol interference of Cyclic Prefix in each OFDM symbol to reduce to cause by channel time delay expansion.This Cyclic Prefix is different from the Cyclic Prefix in the preamble.Yet two purposes of Cyclic Prefix being added to preamble also comprise and can the processing channel time delay expansion obtain better channel estimating with the long preamble of use.Next, fast Fourier transform (FFT) module 935 is transformed to frequency-region signal with signal (time-domain signal).Rearrange the output of the symbol deinterleaver 940 use FFT935 of FFT output for de-mapping device 945.De-mapping device 945 is converted to bit stream in the time domain with frequency-region signal (complex signal).Position deinterleaver 950 as before rearrange bit stream in the original bit stream sequence the interleaver 825 of Fig. 8.

Follow a deinterleaving closely, fec decoder device 955 decoding bit streams, thus remove the redundancy that the FEC820 by Fig. 8 adds.In one embodiment, fec decoder device 955 comprises demodulation multiplexer, multiplexer and a plurality of convolution codes (CC) decoder between demodulation multiplexer and multiplexer.At last, descrambler 960 receives from the output of fec decoder device 955 and with its descrambling, thereby produces the video data by transmitter 800 transmissions of Fig. 8 again.Video-unit 965 can use video data to come display video now.The example of video-unit comprises, but is not limited to: CRT TV, LCD TV, rear-projection TV and plasma show TV.Should be appreciated that voice data also can be handled in an identical manner and send with video data by above-mentioned wireless HD A/V system.Can use different wireless transmission methods that voice data is handled and sent.The descrambler 960 of receiver chain 900, fec decoder device 955, a deinterleaver 950, de-mapping device 945, symbol deinterleaver 940, FFT 935, cyclic prefix remover 930, downconverter 915 and reception antenna 910 are carried out scrambler 815, FEC 820, position interleaver 825, mapper 830, symbol interleaver 835, IFFT 840, cyclic prefix adder 845, up conversion 860 and the transmitting antenna 865 similar still reverse functions with transmit chain 800.

In a particular embodiment, channel estimating, synchronously and timing recovery assembly 925 comprise digital circuit (such as, the part of field programmable gate array (FPGA)).Assembly 925 is by handling short training sequence and extracting channel status with reprocessing long training sequence (Fig. 4 and Fig. 7).Channel status can change and the reflection current channel condition according to bag.Wireless channel can by environmental factor (such as, people or pet moves etc. in the room) and change.Channel knowledge affects data determines and can be used by some or all assemblies 930 to 960 shown in the dotted line among Fig. 9.Comprise by the channel status of handling the short training sequence acquisition: thick frequency offset estimating, thick sequential are estimated and automatic gain control.Comprise by the channel status of handling the long training sequence acquisition: channel estimating, smart frequency offset estimating and smart sequential are estimated.

Conclusion

Above detailed description has illustrated, has described and pointed out the fundamental novel features of the present invention that is applied to various embodiment, be appreciated that under situation about not breaking away from those of ordinary skill in the art can carry out various omissions in form and details, substitutes and change by purpose of the present invention.

Claims (26)

1, a kind ofly on wireless channel unpressed video information is sent to the method for receiver from transmitter, this method comprises:

Provide unpressed video information bits at transmitter;

Video information bits is bundled to one or more bags;

Provide preamble before the data in each bag, wherein, this preamble comprises one group of short training sequence and group leader's training sequence; And

On wireless channel, a plurality of bags are sent to receiver from transmitter.

2, the method described in claim 1 wherein, was inserted into described preamble in the bag before symbol shaping, up conversion and transmission.

3, the method described in claim 1, wherein, the total length of described preamble is five OFDMs (OFDM) symbol lengths.

4, the method described in claim 1, wherein, each short training sequence is 256 samples.

5, the method described in claim 1, wherein, each long training sequence is 512 samples.

6, the method described in claim 1, wherein, described one group of short training sequence comprises seven short training sequences, described group leader's training sequence comprises two long training sequences.

7, the method described in claim 1, wherein, described one group of short training sequence comprises the repetition of particular sequence, last repeating is rotated 180 degree.

8, the method described in claim 1, wherein, described one group of short training sequence comprises the repetition of particular sequence, last repeating is not rotated 180 degree.

9, the method described in claim 1, wherein, the protection of length 64 separates described one group of short training sequence at interval with described group leader's training sequence.

10, the method described in claim 1, wherein, described preamble comprises the protection interval of the short training sequence of seven length 256, a length 64 and the long training sequence of two length 512, total length is five OFDMs (OFDM) symbols.

11, the method described in claim 1 wherein, uses Quadrature Phase Shift Keying (QPSK) signal to define each short training sequence on frequency domain, uses binary phase shift keying (BPSK) signal to define each long training sequence on frequency domain.

12, a kind of system that is used for the radio communication of unpressed high definition video with preamble design, this system comprises:

Transmitter is configured to produce with high definition video and flows corresponding signal packet, and wherein, described each signal packet comprises head part and data division, and wherein, described head part starts from having the preamble of one group of short training sequence and group leader's training sequence; With

Wireless channel is configured to send the signal packet that the unpressed high definition video of expression flows.

13, the system described in claim 12 wherein, uses Quadrature Phase Shift Keying (QPSK) signal to define each short training sequence on frequency domain, uses binary phase shift keying (BPSK) signal to define each long training sequence on frequency domain.

14, the system described in claim 12, wherein, the total length of described preamble is five OFDMs (OFDM) symbol lengths.

15, the system described in claim 12, wherein, each short training sequence is 256 samples.

16, the system described in claim 12, wherein, each long training sequence is 512 samples.

17, the system described in claim 12, wherein, described one group of short training sequence comprises seven short training sequences, described group leader's training sequence comprises two long training sequences.

18, the system described in claim 12, wherein, described one group of short training sequence comprises the repetition of particular sequence, last repeating is rotated 180 degree.

19, the system described in claim 12, wherein, described one group of short training sequence comprises the repetition of particular sequence, last repeating is not rotated 180 degree.

20, the system described in claim 12, wherein, the protection of length 64 separates described one group of short training sequence at interval with described group leader's training sequence.

21, the system described in claim 12, wherein, described preamble comprises the protection interval of the short training sequence of seven length 256, a length 64 and the long training sequence of two length 512, total length is five OFDMs (OFDM) symbols.

22, a kind ofly on wireless channel unpressed video information is sent to the system of receiver from transmitter, this system comprises:

The device of unpressed video information bits is provided at transmitter;

Video information bits is bundled to the device of one or more bags;

The device of preamble is provided before the data in each bag, and wherein, this preamble comprises one group of short training sequence and group leader's training sequence; And

On wireless channel, a plurality of bags are sent to the device of receiver from transmitter.

23, the system described in claim 22, wherein, each short training sequence is 256 samples.

24, the system described in claim 22, wherein, each long training sequence is 512 samples.

25, the system described in claim 22, wherein, described preamble comprises the protection interval of the short training sequence of seven length 256, a length 64 and the long training sequence of two length 512, total length is five OFDMs (OFDM) symbols.

26, the system described in claim 22 wherein, uses Quadrature Phase Shift Keying (QPSK) signal to define each short training sequence on frequency domain, uses binary phase shift keying (BPSK) signal to define each long training sequence on frequency domain.

Images