EP1938624A2 - Appareil et procédé pour une transmission sans fil d'une vidéo non compressée - Google Patents

Appareil et procédé pour une transmission sans fil d'une vidéo non compressée

Info

Publication number
EP1938624A2
EP1938624A2 EP06836492A EP06836492A EP1938624A2 EP 1938624 A2 EP1938624 A2 EP 1938624A2 EP 06836492 A EP06836492 A EP 06836492A EP 06836492 A EP06836492 A EP 06836492A EP 1938624 A2 EP1938624 A2 EP 1938624A2
Authority
EP
European Patent Office
Prior art keywords
coefficients
symbol
values
video signal
value
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP06836492A
Other languages
German (de)
English (en)
Other versions
EP1938624A4 (fr
Inventor
Zvi Reznic
Nathan Elnathan
Meir Feder
Shay Freundlich
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Amimon Ltd
Original Assignee
Amimon Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US11/551,641 external-priority patent/US8559525B2/en
Priority claimed from US11/551,654 external-priority patent/US7860180B2/en
Application filed by Amimon Ltd filed Critical Amimon Ltd
Publication of EP1938624A2 publication Critical patent/EP1938624A2/fr
Publication of EP1938624A4 publication Critical patent/EP1938624A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N11/00—Colour television systems
    • H04N11/04—Colour television systems using pulse code modulation
    • H04N11/042—Codec means
    • H04N11/044—Codec means involving transform coding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
    • H04L27/3488—Multiresolution systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/124—Quantisation
    • H04N19/126—Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/18—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being a set of transform coefficients
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/30—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using hierarchical techniques, e.g. scalability
    • H04N19/36—Scalability techniques involving formatting the layers as a function of picture distortion after decoding, e.g. signal-to-noise [SNR] scalability
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems

Definitions

  • the invention relates to the transmission of uncompressed video over a wireless link. More specifically, the invention relates to the delay-less and buffer-less transmission of uncompressed HDTV video over a wireless link using direct mapping of image transform coefficients to transmission symbols.
  • television and/or video signals are received through cable or satellite links at a set-top box at a fixed point in the house.
  • a screen at a point a distance from the set-top box by a few meters.
  • LCD liquid crystal display
  • Connection of the screen to the set-top box through cables is generally undesired for aesthetic reasons and/or installation convenience.
  • wireless transmission of the video signals from the set-top box to the screen is preferred.
  • the data are received at the set-top box compressed in accordance, for example, with the motion picture expert group (MPEG) format and are decompressed by the set-top box to a high quality raw video signal.
  • the raw video signal may be in an analog format or a digital format, such as the digital video interface (DVI) format or the high definition multimedia interface (HDMI) format.
  • DVI digital video interface
  • HDMI high definition multimedia interface
  • These digital formats generally have a high definition television (HDTV) data rate of up to about 1.5 Giga bits per second (Gbps). in the home can be done over the unlicensed bands around 2.4GHz or around 5GHz (e.g., in the U. S 5.15-5.85 GHz band).
  • WLAN wireless local area networks
  • 802.11 WiFi standard allow maximal data rates of 11Mbps (802.11b), or 54Mbps (for 20MHz bandwidth and the 802.11g/802.11a standards).
  • Wi-Fi wireless local area networks
  • Wi-Fi Wireless Fidelity
  • the method includes providing high definition video, compressing the video using an image domain compression method, in which each pixel is coded based on a vicinity of the pixel, and transmitting the compressed video over a fading transmission channel.
  • signals are transmitted in the form of symbols.
  • Each symbol can have one of a predetermined number of possible values.
  • the set of possible values of each symbol is referred to as a constellation and each possible value is referred to as a constellation point.
  • the distance between neighboring points affects the immunity to noise.
  • the noise causes reception of another point instead of the intended point, and thus the symbol may be interpreted incorrectly.
  • OFDM orthogonal frequency division multiplexing
  • the symbols are comprised of multiple bins, e.g., 64, 128 or 256 bins, in the frequency domain, each bin of each symbol comprised of a two dimensional constellation. It is also known in the art that the use of some of the available bins is not recommended. Typically these are the bins located at the ends of the transmission band. Typically, for example in 802.11a/g, some 16 available channels out of the 64, are not used, and hence the efficiency of the band is reduced.
  • An apparatus and method for wireless transmission of uncompressed HDTV video overcomes the challenges of sending vast amounts of information over a wireless link. This is achieved by direct mapping of transformation coefficients of the video components (for example Y-Cr-Cb components) to communication symbols, such as OFDM symbols.
  • a main portion of the important transform coefficients for example the most significant bits of the coefficients representing lower frequencies of each of the video components, and in particular the quantized values of the DC and the near DC components thereof, are sent in a coarse, digital, representation using, for example, QPSK or QAM.
  • the coefficients representing the higher frequency of each of the video components, as well as the quantization error values of the DC and near DC components, or some, possibly non-linear transformation thereof, are sent as pairs of real and imaginary portions of a complex number that comprises a point in a fine granularity constellation.
  • the invention thus provides a delay-less and buffer-less implementation of transmitter and receiver pairs.
  • Fig. 1 is a block diagram of coding system in accordance with the disclosed invention.
  • Fig. 2 is a schematic diagram showing an 8-by-8 pixel de-correlation transform, the grouping of the coefficients, and the mapping into coarse and fine symbol representations in accordance with the disclosed invention
  • Fig. 3 is a table showing the number of coefficients selected from each of the transformed Y, Cr and Cb of an 8-by-8 pixel conversion in accordance with an embodiment described in the disclosed invention
  • Fig. 4 is a flowchart describing the principles of the disclosed invention.
  • Fig. 5 is a flowchart showing handling an HDTV video for wireless transmission using OFDM scheme in accordance with the disclosed invention
  • Fig. 6 is a detailed block diagram of a coding system in accordance with the disclosed invention.
  • Fig. 7 is a block diagram of the bit manipulation block of a coding system in accordance with the disclosed invention.
  • Fig. 8 is a block diagram of a receiver enabled to receive a video steam transmitted in accordance with the disclosed invention.
  • the disclosed invention is intended to overcome the deficiencies of the prior art solutions by providing a scheme that allows the transmission of video, such as a high- definition television (HDTV) video, over a wireless link using transmission symbols, such as symbols of an OFDM scheme.
  • video such as a high- definition television (HDTV) video
  • transmission symbols such as symbols of an OFDM scheme.
  • the inventors have realized that it is possible to map the coefficients of a block of pixels, or a portion thereof, after a de- correlating transformation directly into the transmission symbols.
  • the de-correlation is performed for the purpose of minimizing the energy of the coefficients but without compromising the number of degrees of freedom available.
  • a discrete cosine transform (DCT) is performed on a block of pixels of each of the Y, Cr and Cb components of the video.
  • DCT discrete cosine transform
  • the Y component provides the luminance of the pixel, while the Cr and Cb components provide the color difference information, otherwise known as chrominance.
  • all the coefficients are transmitted in accordance with the disclosed invention.
  • only a portion of the coefficients are used for transmission purposes, thereby frequency coefficients and keeping the lower spatial frequency coefficients.
  • more of the Y related coefficients are preserved for wireless transmission purposes than those for the other two components, as the human eye is more sensitive to luminance then chrominance.
  • a ratio of at least three coefficients respective of the Y component may be used for each of the Cr and Cb components, e.g. a ratio of 3:1 :1.
  • the invention further sends the information of the quantization error over the transmission channel thereby allowing the reconstruction of the video frame and providing an essentially uncompressed transmission of video, and in particular high- 5 definition video, over a transmission channel, wired or wireless.
  • the DC coefficients, or DC proximate coefficients having a larger value are represented in a coarse, sometimes referred to as digital, manner, i.e. part of the DC value is represented as one of a plurality of constellation 0 points of a symbol. This is achieved by performing a quantization on these values and mapping those quantized values in accordance with the disclosed invention.
  • the higher frequency coefficients and in addition the quantization errors of the DC and the DC proximate components whose main part is presented coarsely, are grouped in pairs, positioning each pair in a point as the real and imaginary values of the complex 5 number, that provide the fine granularity, almost analog, value which at an extreme fineness provides for a continuous representation of these values.
  • a non-linear transformation is performed on any one of these values that comprise the complex number.
  • Companding is a non- 0 linear transformation of a value.
  • Common companding functions are logarithmic, e.g., A-law and ⁇ -law. The use of these techniques effectively provide for a better dynamical range and better signal-to-noise ratio in representing the corresponding values.
  • the following companding function may be used' S J! Pu ⁇ heM ?y fte vil ⁇ iy'ofllii coefficient and a is a factor designed to maintain the power of f(x) to be the same as that of x.
  • mapping of a number of data values to a smaller 5 number of values thereby potentially saving transmission bandwidth. For example, two numbers are mapped into one number, or three numbers are mapped into two numbers and the likes. While inserting a certain distortion when the original values are reconstructed, the advantage is the capability of sending also the less important data on the limited available bandwidth.
  • two numbers for example x ?
  • the data transferred may be encrypted.
  • the invention disclosed herein allows keeping all the coefficients of the de-correlating transform. Therefore the reconstruction at the receiver 0 side is more accurate as more information is available for such reconstruction. Furthermore, in accordance with the disclosed invention it is possible to use subchannels of the transmission channel, normally avoided so as to provide necessary margin or to avoid interference problems, for the purpose of transmitting those coefficient values which receive a lesser representation. By transmitting the less 5 important values as determined in accordance with the disclosed invention, over the normally un-used sub-channels, or subbands, effectively there is an increase of the available bandwidth for transmission. In addition some values can be compacted together using the methods described hereinabove.
  • OFDM orthogonal frequency division modulation
  • symbols are comprised of multiple domain, each bin of each symbol comprised of a two dimensional constellation (a complex number).
  • W there are 2W degrees of freedom. If the spectral efficiency p is less than 100% then the number of degrees of freedom is 2Wp per second. Since each complex
  • 5 number contains two degrees of freedom the number of complex number that can be transmitted is pW.
  • MIMO multi-in multi-input multi-output
  • Fig. 1 shows an exemplary and non-limiting block diagram of system 100 for direct symbol coding in accordance with the disclosed invention.
  • the system 100 receives the red-green-blue (RGB) components of a video signal, for example an HDTV video signal.
  • the RGB stream is converted in the color conversion block 110 to the luminance component Y, and the two color difference components, Cr and Cb. This 0 conversion is well known to persons of ordinary skill in the art.
  • the video begins with a Y-Cr-Cb video signal and, in such a case, there is no need for the color conversion block 110.
  • the Y-Cr-Cb components are fed to a transform unit 120 where a de-correlating transformation is performed on blocks of pixels respective of each of the three components.
  • the block 120 performs a DCT on the blocks of pixels.
  • a block of pixels may contain 64 pixels arranged in an 8-by-8 format, as shown in to Fig. 2.
  • the transform unit 120 may comprise a single subunit for performing the desired transform, for example a DCT, handling the conversions for all the blocks of pixels of an entire video frame for each of the Y-Cr-Cb component.
  • a dedicated 0 transform subunit is used for each of the Y-Cr-Cb components, thereby accelerating the performance of the system.
  • a plurality of subunits are used such that two or more such subunits, capable of performing a desired transform on a block of pixels, are used for each of the Y-Cr-Cb components, thus further accelerating the performance of the system 100.
  • the output of transform unit 120 is a are fed to a mapper 130.
  • the mapper 130 selects those coefficients from each of the Y-Cr-Cb components which are to be transferred over the wireless link.
  • the mapper 130 also maps the coefficients to be sent to transmission symbols, for example, the symbols of an orthogonal frequency division multiplexing 5 (OFDM) scheme, a process described in more detail with respect to Fig. 4.
  • OFDM orthogonal frequency division multiplexing 5
  • a modified OFDM transmitter 140 that handles the mixed nature of the symbols having a mix of coarse and fine constellation values, as explained in more detail with respect to Fig 2.
  • a modified OFDM transmitter 140 is connected to a plurality of antennas for 0 the purpose of supporting a multi-input, multi-output (MIMO) transmission scheme, thereby increasing the effective bandwidth and reliability of the transmission.
  • MIMO multi-input, multi-output
  • a receiver for example the receiver shown in Fig. 8, adapted to receive the wireless signal comprising the symbols transmitted in accordance with the disclosed invention, must be capable of detecting the coarse and 5 fine representations of the sent symbols, reconstruct the respective coefficients, and perform an inverse transform to reconstructing the Y-Cr-Cb components.
  • a de-correlating transform such as a DCT, 5 is performed on blocks of pixels, for example 8-by-8 pixels, on each of the Y-Cr-Cb components of the video.
  • a two dimensional coefficient matrix 220 is created.
  • the coefficients closer to the origin, in the area 222, are generally the low frequency and DC portions of each of the Y-Cr-Cb components, such as the coefficient 222-i.
  • Higher 0 frequency coefficients may be found in the area 224, such as coefficients 224-i, 224-j, and 224-k, generally having a significantly smaller magnitude than the DC components, for example less than half the amplitude of the DC component. Even higher frequencies may be found in the area marked as 226.
  • the inventors have noted that, to keep an essentially uncompressed video, it may be possible to remove the high area 226 for each of the Y-Cr-Cb components.
  • the area 226 may be smaller or larger depending on the number of coefficients that may be sent in a particular implementation.
  • the main portion of the DC coefficient for example the most significant bits of the coefficient 222-i, is preferably mapped into one of a plurality
  • a constellation map may be a 4QAM (QPSK), 16QAM, or any other appropriate type. Because four constellation points 231 through 234 are shown in constellation map 230, a 4QAM implementation is taught in this embodiment, and each of the constellation points is mapped to a digital value from 00 to 11 , respectively. The quantized value of 0 coefficient 222-i is mapped to one such constellation point, depending on its specific value. Such a mapping is considered a digital value mapping.
  • this coarse representation is also likely to have a quantization error, or in other words, a value corresponding to the difference between the original value and 5 the value represented by the coarse representation.
  • This error essentially corresponds to the least significant bits of the high importance coefficients' values that were quantized.
  • the quantization error value, as well as coefficients not represented in a coarse manner, i.e., the coefficients associated with the higher frequencies of area 224, may be mapped as part of constellation point 240-i as, for example, the real 0 portion of the complex number constituting the symbol 240-i.
  • the higher frequency coefficients are paired and each pair is mapped to a constellation point as a real portion and an imaginary portion of a complex number.
  • the coefficients 224-i and 224-j may be mapped to the imaginary and real portions of a constellation point 240-j. This allows for a continuous representation effectively using any available 5 point in the constellation mapping, or otherwise providing a fine constellation. Such a mapping is considered continuous value mapping.
  • a receiver enabled to receive the symbol stream disclosed herein should be able to recompose the coefficients 0 from the transmitted symbols, and is discussed in more detail below.
  • the inventions of MIMO with continuous representation and OFDM with continuous representation provide advantages over the prior art. Specifically, only simple and straightforward algebraic computation is necessary for the reception of the fine values of the transmitted video stream. Even if some errors occur, the impact on the quality of the and generally non-observable.
  • MIMO and/or OFDM systems sending pure data, including video transmitted as data rather than that in the manner disclosed in this invention requires significantly more compute power, and more bandwidth, generally not readily available, and the video quality is more
  • FIG. 3 An exemplary reference may be found in Fig. 3, where an 8-by-8 coefficient matrix is assumed and, hence, there are 64 coefficients found for each of the Y-Cr-Cb components. However, for the reasons mentioned hereinabove, typically between 28- 0 64 of the coefficients of the Y component, and 12-64 of each of the Cr and Cb components are transmitted over the wireless link. The exact number of coefficients may be determined based on the available number of OFDM symbols, where each bin of the OFDM symbol has two degrees of freedom, available for wireless transmission, and on the desired level of reliability of the wireless transmission.
  • a 20 MHz OFDM 5 channel allows for up to 2OM complex numbers, 2OM real and 2OM imaginary, per second, i.e., 4OM degrees of freedom per second.
  • spectral efficiency of the disclosed solution is typically ⁇ 75% and hence each transmission channel can deliver about 3OM degrees of freedom per second or a total of 120M degrees of freedom per second, in the discussed example.
  • some of the channels are used to transmit the coarse representation and the rest to transmit the 5 fine representation. More degrees of freedom are provided to the more important coefficients while less degrees of freedom are provided to the less important coefficients, or even quantization errors thereof.
  • a single frame is contained in about 1200 OFDM symbols corresponding to 256 bins, and which contain the information of about 14,400 blocks of 8-by-8 pixels.
  • the use of a 40 MHz bandwidth channel will allow the sending of twice the number of coefficients and thus more of the coefficients more accurately, for example, it may allow sending the coarse information that has higher importance in a more robust manner, by repeating the information in the course of transmission.
  • ⁇ M(feW ⁇ &lb ⁇ Wfe ⁇ li>vwjhart 400 describing the principles that are at the core of the disclosed invention.
  • a video stream undergoes a de-correlating transformation.
  • the fine representation data undergoes non- linear transformations, as explained in more detail above.
  • the fine representation values are mapped into pairs of real and imaginary portions of symbols.
  • the created symbols are transmitted in accordance with the disclosed invention.
  • Fig. 5 shows an exemplary and non-limiting flowchart 500 of the handling of an HDTV video for wireless transmission using the OFDM scheme in accordance with the disclosed invention.
  • a RGB video is received.
  • the RGB is converted to a Y-Cr-Cb video data stream.
  • a Y-Cr- Cb video is provided and, therefore, the conversions discussed with respect to S510 and S520 are not necessary.
  • a de-correlating transform is performed, for example DCT, on each of the plurality of blocks of pixels, for example a block of 8-by-8 pixels, of each of the Y-Cr-Cb components of the video.
  • a plurality of coefficients is created as a result for each block, for example 64 coefficients in the case of the 8-by-8 block.
  • the number of coefficients to be transmitted is selected.
  • S550 through S570 provide a more detailed description of the mapping process discussed with respect to Figs. 1 , 2 and 4 above.
  • the coefficients in the DC p li ⁇ t ⁇ f ⁇ naM fenlgW are handled.
  • their amplitude is significantly higher than that of the rest of the coefficients, i.e., their most significant bits (MSBs) are material for the information to be sent, and hence these form the coarse representation. Therefore, the MSBs of these coefficients are mapped separately and differently from their respective least significant bits (LSBs), which are otherwise referred to as the quantization error of the DC coefficient.
  • MSBs most significant bits
  • the three MSBs are separated from the rest of the bits as a coarse representation, and transferred as a symbol of its own.
  • the coarse representation is repeated in several symbols for the purpose of ensuring proper and robust reception because the loss of this information is significant for the quality of the reconstructed image.
  • the coarse representation is sent as explained in more detail with respect to Fig. 2 above.
  • error correction code is used to assure the robust reception of these bits.
  • the error correction may further be an unequal error correction which is described in detail in US provisional patent application serial number 60/752,155, entitled “An Apparatus and Method for Unequal Error Protection of Wireless Video Transmission", assigned to common assignee and which is hereby incorporated by reference for all the useful information it may contain
  • the more important coefficients are represented by more of the MSBs versus other coefficients represented by fewer MSBs
  • the LSBs of the DC component that (as noted above) have an amplitude described by the LSBs, for example 8 LSBs of an 11- bit value, as well as the rest of the higher frequency coefficients, construct the fine representation of the coefficients and may be mapped as explained with respect of S560 and S570, as further discussed with reference to Fig 2 above
  • Each pair of the fine representation values may be viewed as the real and imaginary components of a complex value which establishes a symbol of the OFDM scheme Therefore, if there are 230 available symbols for transmission in a given time slot, it is possible to
  • pilots are sent as a priori known signals in some bins of the OFDM symbol, preferably a value from a QPSK constellation. These pilots, alone or in conjunction with other pilots, are used in standard modems for synchronization, frequency, phase corrections, and the like. Pilots can also help in channel estimation and equalization. In standard digital modem, these pilots together with the digital information values, the latter being used via decision feedback because these values are known to those skilled in the art after decoding, allow robust channel estimation and tracking. In the invention disclosed herein, the analog data, sent in the manner discussed in more detail above, makes the use of decision feedback impossible.
  • additional pilots are sent to ensure stable channel estimation and tracking.
  • These pilots may now be used for the purpose of sending the digital data discussed in more detail above, i.e. the coarse values of some transform coefficients are sent over these pilots.
  • additional pilot signals are sent, there is more room for coarsely represented data.
  • SNR signal-to-noise ratio
  • the higher importance coefficients can now be sent more than once thereby increasing the noise immunity for such high importance coefficients.
  • Fig. 6 shows an exemplary and non-limiting block diagram 600 of a system designed to handle the coding in accordance with the disclosed invention.
  • a base band modulator is divided into five basic blocks, according to the functionality and working domain of each bock.
  • the modulator input consists of four signals: one is a symbol stream of the fine data, the result of the transform discussed in more detail above with respect to the handling of the quantization error values of the higher importance P&ifflc ⁇ A ⁇ feftiKrtA ⁇ b'& ⁇ iM ⁇ i ⁇ ntB identified to be of lower importance.
  • the other is a bit stream that represents the coarse part of the DC values of, for example, Y, Cr and Cb components, and possibly the coarse part of some other components as explained in more detail above with respect of the MSBs of the coefficients above.
  • These streams are supplied from video coder 610.
  • the signals from modem control 670 consists of a number of control commands that are to be passed to the receiver, for example the receiver of Fig. 8, as well as other control signals to control the modulator.
  • the modulator output consists of a plurality of signals, for example four signals, that carry the information to digital-to- analog converter 660. This allows for the implementation of MIMO transmission as discussed above.
  • Fig. 7 shows an exemplary and non-limiting block diagram of bit manipulation unit (BMU) 620 of the system 600.
  • the BMU 620 is capable of performing all bit manipulations on the data bits themselves. There are no quantization errors handled by the BMU 620, and all operations are performed bitwise.
  • the audio and coarse representation bit streams are arranged in a predefined order and create a single bit stream by the bit arrangement unit 622.
  • the bits of the single bit stream are mapped to the desired constellation by B2S mapper 626 and passed to a framer unit 630.
  • the framer unit 630 receives the single bit stream and the fine bit stream as a number of sample streams and organizes it into four sample streams with an appropriate header, pilots, and so on.
  • the frequency domain unit (FDU) 640 gets its inputs from the framer 530.
  • the framer 630 creates a symbol stream, such that each symbol is a complex number in accordance with the disclosed invention, as described hereinabove, that represents a point in the two-dimensional space.
  • the framer 630 also includes an inverse fast Fourier transform (IFFT) operation, and the resultant signal is fed to the time domain unit (TDU) 650 where certain shaping of the signal is performed prior to converting the signal to an analog signal in the digital-to-analog converter (DAC) 660.
  • TDU time domain unit
  • DAC digital-to-analog converter
  • the desirable number of bits can be approximated using the following assumptions: quantization noise of about 6 dB per bit, peak to average (PAR) of the signal ⁇ 14 dB, symbol SNR for a desired bit error rate (BER) and given constellation -22 dB, and a safety margin ⁇ 6 dB.
  • PAR peak to average
  • BER bit error rate
  • a safety margin ⁇ 6 dB a safety margin
  • at least seven bits are required, however, to be on the safe side, and according to the limitations of existing technology, it is recommended to use, without limiting the generality of the disclosed invention, a 10-bit or even 12-bit DAC
  • Fig. 8 shows an exemplary and non-limiting receiver 800 adapted to receive signals transmitted in accordance with the disclosed invention.
  • a demodulator 810 is adapted to receive the symbols transmitted in accordance with the disclosed invention, for example as OFDM symbols. The reception is performed, for example, by means of receiving a wireless transmission received from a plurality of antennas 815. Typically, in a MIMO system, the receiver will have at least one more antenna over the number of channels, or antennas, used by the transmitter.
  • the demodulator 810 receives the signals from antennas 815 and processed according to principles of linear filtering theory by unit 812, that also separates the received streams into the respective coarse and fine streams.
  • the coarse data is decoded directly by a MIMO decoding method, such as sphere decoding, while the fine data is process in accordance with linear filtering theory.
  • the fine stream is handled by the decompanding unit 814 that linearizes the received data and generates the fine stream data.
  • the coarse stream is handled by digital demodulator 816 operative in accordance with standard digital modulation techniques and that generates the coarse stream data.
  • the demodulator provides coarse and fine streams of detected OFDM symbols which are then converted by unit 820 to the coefficients by appropriately reconstructing them. Specifically, the information of the quantization errors is added to the respective coarse values to reconstruct the DC and near DC coefficients. Other fine values construct the high frequency coefficient.
  • the reconstructed coefficients are now provided to the inverse transformation unit 830 that generates the Y, Cr, and Cb components of the video transmission.
  • a color converter unit 840 further converts the luminance and chrominance inputs into a standard RGB output, if so desired.
  • elements such as, but not limited to, decision feedback channel distortions and enable precise reception, channel tracking, timing and carrier tracking, and other components, are not shown, however, such are part of any operable OFDM receiver, are well-known in the art, and hence considered part of the receiver.
  • the receiver 800 may be further enabled to receive pilot signals and interpret them as containing data.
  • An embodiment may include a computer software product containing a plurality of instructions that when executed comprise the inventions disclosed herein.

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  • Multimedia (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)
  • Compression Or Coding Systems Of Tv Signals (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

L'invention concerne un appareil et un procédé pour une transmission sans fil d'une vidéo HDTV non compressée maîtrisant les difficultés d'envoi de grandes quantités d'informations sur une liaison sans fil. Ceci est obtenu par une mise en corrélation directe de coefficients de transformation des composants vidéo avec des symboles de communication, tels que des symboles OFDM. Une partie principale des coefficients de transformation importants, par exemple, les MSB des coefficients représentant des fréquences inférieures de chacun des composants vidéo, et en particulier les valeurs quantifiées des composants de fréquences inférieures, est envoyée dans une représentation grossière à l'aide, par exemple, de QPSK ou QAM. Les coefficients représentant des fréquences supérieures des composants vidéo, et les valeurs d'erreur de quantification des composants de fréquences inférieures, ou une certaine transformation non linéaire de ceux-ci, sont envoyés comme des paires de parties réelle et imaginaire d'un nombre complexe qui comprend un point dans une constellation fine. L'invention concerne en outre une mise en oeuvre sans retard et sans mémoire tampon de paires d'émetteurs et de récepteurs.
EP06836492A 2005-10-21 2006-10-23 Appareil et procédé pour une transmission sans fil d'une vidéo non compressée Withdrawn EP1938624A4 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US72945905P 2005-10-21 2005-10-21
US75215505P 2005-12-19 2005-12-19
US75806006P 2006-01-10 2006-01-10
US11/551,641 US8559525B2 (en) 2005-10-21 2006-10-20 Apparatus and method for uncompressed, wireless transmission of video
US11/551,654 US7860180B2 (en) 2005-10-21 2006-10-20 OFDM modem for transmission of continuous complex numbers
PCT/US2006/041485 WO2007048061A2 (fr) 2005-10-21 2006-10-23 Appareil et procédé pour une transmission sans fil d’une vidéo non compressée

Publications (2)

Publication Number Publication Date
EP1938624A2 true EP1938624A2 (fr) 2008-07-02
EP1938624A4 EP1938624A4 (fr) 2009-10-28

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EP06836492A Withdrawn EP1938624A4 (fr) 2005-10-21 2006-10-23 Appareil et procédé pour une transmission sans fil d'une vidéo non compressée

Country Status (3)

Country Link
EP (1) EP1938624A4 (fr)
JP (1) JP2009513064A (fr)
WO (1) WO2007048061A2 (fr)

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ES2812178T3 (es) * 2016-09-12 2021-03-16 Shidong Chen Método y aparato para transmitir vídeo por medio de canal de múltiple entrada múltiple salida
CN114143557B (zh) * 2021-12-24 2023-07-07 成都索贝数码科技股份有限公司 一种针对视频图像小波变换高频系数的低复杂度编码方法

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Also Published As

Publication number Publication date
WO2007048061A3 (fr) 2009-04-30
WO2007048061A2 (fr) 2007-04-26
EP1938624A4 (fr) 2009-10-28
JP2009513064A (ja) 2009-03-26

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