Adaptive forward error correction
Abstract
EARLY AND ADAPTIVE ERROR CORRECTION. Devices and methods for adaptive early error correction (FEC) are described, an example of use being for continuous video transmission over a wireless network. The apparatus includes an FEC encoder (210) and an adaptive FEC device (240). The FEC encoder (210) serves to encode k source data packets into n packets, where n> k, and the n packets include redundant packets. The adaptive FEC device (240) serves to adaptively determine a number of redundant packets to be transmitted with the k encoded packets, based on the reception of one or more feedback messages. The one or more feedback messages indicate a condition of the wireless network through which the encrypted video will be transmitted.
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25 claims: 4 independent, 21 dependent
- 1REIVINDICAÇÕES 1. Aparelho, CARACTERIZADO por compreender:um codificador para correção antecipada de erros (210) para codificar k pacotes de dados de origem em n pacotes, onde n k, e os n pacotes incluem dados redundantes;e um dispositivo de FEC adaptativa (240) para determinar adaptativamente a quantidade de dados redundantes codificados junto com os k pacotes de dados de origem em n pacotes de dados codificados e redundantes, em resposta à recepção de pelo menos uma mensagem de realimentação.
- 2Aparelho, de acordo com a reivindicação 1, CARACTERIZADO pelo fato de que pelo menos uma mensagem de realimentação indica a condição de uma rede pela qual os ditos dados codificados e redundantes serão transmitidos.
- 3Aparelho, de acordo com a reivindicação 2, CARACTERIZADO pelo fato de que a dita rede é uma rede sem fio.
- 4Aparelho, de acordo com a reivindicação 3, CARACTERIZADO pelo fato de que o dito dispositivo de FEC adaptativa (240) reduz o número de pacotes redundantes em um até um valor mínimo de zero, quando a pelo menos uma mensagem de realimentação indica uma condição satisfatória da rede sem fio.
- 5Aparelho, de acordo com a reivindicação 3, CARACTERIZADO pelo fato de que o dito dispositivo de FEC adaptativa (240) aumenta o número de pacotes· redundantes em um até um valor máximo de n-k pacotes, quando a pelo menos uma mensagem de realimentação indica uma condição insatisfa2 tória da rede sem fio.
- 6Aparelho, de acordo com a reivindicação 2, CARACTERIZADO pelo fato de que os ditos k pacotes de dados de origem incluem, pelo menos em parte, dados de transmissão continua de video.
- 7Aparelho, de acordo com a reivindicação 1, CARACTERIZADO pelo fato de que o dito dispositivo de FEC adaptativa (240) adapta o número de pacotes redundantes a ser transmitido com base em uma função de aumento / redução.
- 8Aparelho, de acordo com a reivindicação 1, CARACTERIZADO pelo fato de que a pelo menos uma mensagem de realimentação compreende relatórios do receptor RTCP (Protocolo de Controle em Tempo Real) que especificam uma fração de pacote perdida e um número cumulativo de pacotes perdidos.
- 9Aparelho, de acordo com a reivindicação 2, CARACTERIZADO pelo fato de que a condição da rede é determinada em relação a um limiar predeterminado que se baseia em uma taxa real de bits recebidos versus uma taxa de bits oferecida para transmissão.
- 10Aparelho, de acordo com a reivindicação 9, CARACTERIZADO pelo fato de que o dito dispositivo de FEC adaptativa (240) aumenta o número de pacotes redundantes para a ser transmitido quando a taxa real de bits recebidos e a taxa de bits oferecida para transmissão estiverem aumentando.
- 11Aparelho, de acordo com a reivindicação 1, CARACTERIZADO pelo fato de que a pelo menos uma mensagem de realimentação corresponde à informação de retransmissão nas camadas de nivel inferior de um hardware de interface sem fio.
- 12Aparelho, de acordo com a reivindicação 1, CARACTERIZADO pelo fato de que o dito codificador FEC (210) codifica os k pacotes de dados de origem usando a FEC em nível de pacote de apagamento.
- 13Método para correção de erros antecipada e adaptátiva (FEC) para transmissão contínua de vídeo por meio de uma rede sem fio, CARACTERIZADO por compreender as etapas de:codificar (410) k pacotes de dados de origem em n pacotes, onde n k, e os n pacotes incluem dados de origem derivados dos k pacotes junto com dados redundantes;e determinar adaptativamente (420, 430) a quantidade dos ditos n pacotes em que serão transmitidos os ditos dados de origem derivados dos k pacotes e dos ditos dados redundantes, em resposta à recepção de pelo menos uma mensagem de realimentação que indica uma condição da rede sem fio.
- 14Método, de acordo com a reivindicação 13, CARACTERIZADO pelo fato de que a dita etapa de determinar ativamente compreende a etapa de adaptar o número de pacotes redundantes a ser transmitido com base em uma função de aumento / redução.
- 15Método, de acordo com a reivindicação 14, CARACTERIZADO pelo fato de que a dita etapa de adaptação reduz (425) o número de pacotes redundantes em um até um valor mínimo de zero, quando a pelo menos uma mensagem de realimentação indica uma condição satisfatória da rede sem fio, a condição satisfatória.
- 16Método, de acordo com a reivindicação 14, CARACTERIZADO pelo fato de que a dita etapa de adaptação aumenta (450) o número de pacotes redundantes em até um valor máximo de n - k pacotes, quando a pelo menos uma mensagem de realimentação indica uma condição insatisfatória da rede sem fio.
- 17Método, de acordo com a reivindicação 13, CARACTERIZADO pelo fato de que a pelo menos uma mensagem de realimentação compreende relatórios do receptor RTCP (Protocolo de Controle em Tempo Real) que especificam uma fração de pacote perdida e um número cumulativo de pacotes perdidos.
- 18Método, de acordo com a reivindicação 13, CARACTERIZADO pelo fato de que a condição da rede é determinada em relação a um limiar predeterminado que se baseia em uma taxa real de bits recebidos versus uma taxa de bits oferecida para transmissão.
- 19Método, de acordo com a reivindicação 18, CARACTERIZADO pelo fato de que a dita etapa de determinação aumenta (450) o número de pacotes redundantes a ser transmitido quando a taxa real de bits recebidos e a taxa de bits oferecida para transmissão estiverem aumentando.
- 20Método, de acordo com a reivindicação 13, CARACTERIZADO pelo fato de que da rede sem fio compreende hardware de interface sem fio, e a uma ou mais mensagens de realimentação correspondem à informação de retransmissão em camadas de nível inferior do hardware de interface sem fio.
- 21Método, de acordo com a reivindicação 13, CARACTERIZADO-' pelo fato de que a dita etapa de determinação compreende a etapa de impedir um aumento do número de pacotes redundantes a ser transmitido quando for recebida uma taxa de pacotes inferior à transmitida dos n pacotes codificados .
- 22Método, de acordo com a reivindicação 21, CARACTERIZADO pelo fato de que a dita etapa de determinação compreende a etapa de reduzir (425) o número de pacotes redundantes a ser retransmitido quando for recebida uma taxa de pacotes inferior à transmitida dos n pacotes codificados.
- 23Método, de acordo com a reivindicação 13, CARACTERIZADO pelo fato de que a dita etapa de codificação (410) codifica os k pacotes de dados de origem usando a FEC em nível de pacote de apagamento.
- 24Método de correção antecipada de erros (FEC), CARACTERIZADO por compreender:codificar (410) k pacotes de dados de origem e (nk) pacotes de dados redundantes juntos em n pacotes;e determinar (420, 430) a quantidade dos ditos n pacotes em que serão transmitidos os ditos dados de origem e os ditos dados redundantes, em resposta à recepção de pelo menos uma mensagem de realimentação referente à condição de uma rede por meio da qual os ditos n pacotes deverão ser transmitidos.
- 25Aparelho para correção antecipada de erros (FEC) , CARACTERIZADO por compreender:meios para codificar (210) k pacotes de dados de origem e (n-k) pacotes de dados redundantes juntos em n pacotes;e meios para determinar (240) a quantidade dos ditos n pacotes em que serão transmitidos os ditos dados de origem e os ditos dados redundantes, em resposta à recepção de pelo menos uma mensagem de realimentação referente à condição de 5 uma rede por meio da qual os ditos n pacotes deverão ser transmitidos. 100 Dados de origem (k pacotes) Codificador Dados codificados (N pacotes) __-150
Independent claims25
54 paragraphs in 1 section, as filed
(54) Title: EARLY AND ADAPTIVE ERROR CORRECTION (30) Unionist Priority: 12/2/2004 us 60 / 632,489 (71) Depositor (s): Thomson Licensing (FR) (72) Inventor (s): Izzat Hekmat Izzat , Mary Lafuze Comer, Thomas Anthony Stahl (74) Attorney: Nellie Anne Daniel Shores (86) International Application: pct US2005 / 020928 of 06/14/2005 (87) International Publication: wo 2006/060036 of 08/06/2006 ( 57) Summary: EARLY AND ADAPTIVE ERROR CORRECTION. Devices and methods for adaptive early error correction (FEC) are described, an example of use being for continuous video transmission over a wireless network. The apparatus includes an FEC encoder (210) and an adaptive FEC device (240). The FEC encoder (210) serves to encode k source data packets into n packets, where n> k, and the n packets include redundant packets. The adaptive FEC device (240) serves to adaptively determine a number of redundant packets to be transmitted with the k encoded packets, based on the reception of one or more feedback messages. The one or more feedback messages indicate a condition of the wireless network through which the encrypted video will be transmitted.
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EARLY AND ADAPTIVE ERROR CORRECTION
Cross Reference to Related Orders
This claim claims the benefit of US Provisional Order N-Series 60 / 632,489 (Case N-PU040331), filed on December 2, 2004 and entitled ADAPTIVE FORWARD ERROR CORRECTION (FEC) FOR VIDEO STREAMING OVER
WIRELESS NETWORKS, incorporated in its entirety into this document as a reference.
Field of the Invention
The present invention is generally related to early error correction (FEC).
Background of the Invention
The error rate of wireless networks is often not sufficient for video applications due to the large possible number of large packet loss / elimination. Sometimes lost or deleted packets are not recovered, but on systems where packet recovery is implemented, packets are recovered by retransmission or early error correction (FEC), or by a combination of both. The FEC allows you to recover data contained in corrupted packages, deleted or lost through the transmission of redundant information, which can be used by the receiver to reconstruct lost data. FEC offers faster data recovery speed than retransmission and does not require a feedback channel. Static FEC techniques have been used by many researchers, but fail to adapt the FEC header to channel and network conditions.
The use of FEC in wireless networks is an area of active research in wireless video applications. An advantage of FEC is that it works satisfactorily with Multicast. In addition, FEC does not require interaction with the video encoder, and therefore is applicable to any video encoding technique and to videos stored or transmitted in real time. However, static FEC algorithms can degrade performance due to the lack of correlation between network resources and the amount of redundancy added by such algorithms, which consume the limited bandwidth of the wireless network.
Adaptive FEC techniques proved to be favorable to the performance of the network. All adaptive techniques require feedback to estimate the available network bandwidth and then adapt the amount of redundancy based on the feedback. The feedback can be explicit, such as RTCP (Real Time Control Protocol) reports, or implicit, such as the use of packet retransmission in the lower layers of a wireless transmitter. In general, the adaptation mechanism increases the number of redundant packets to be sent if the condition of the network is unsatisfactory. If the condition of the network is satisfactory, then no redundant packets need to be transmitted, or only a small number of redundant packets need to be transmitted. Much of the prior art approaches are focused on bit-level FEC.
Summary of the Invention
These and other disadvantages and problems of the prior art are addressed by the present invention, which is concerned with adaptive early error correction (FEC). An application for the adaptive FEC of the present invention would be in the continuous transmission of video between wireless networks.
According to an aspect of the present invention, an adaptive FEC apparatus is provided. The apparatus includes an FEC encoder and an adaptive FEC device. The FEC encoder serves to encode k source data packets into n packets, where n> k, and the n packets include redundant packets. The adaptive FEC device serves to adaptively determine a number of redundant packets to be transmitted with the k encoded packets, based on at least one feedback message. At least one feedback message can indicate the condition or state of the network through which packets encoded by the FEC are to be transmitted.
These and other aspects, characteristics and advantages of the present invention will become apparent from the following detailed description of the illustrative embodiments, which must be read in connection with the accompanying drawings.
Brief Description of Drawings
The present invention can be understood more fully according to the following illustrative figures, in which:
FIG. 1 illustrates a diagram for an illustrative encoding / decoding error correction (FEC) process to which the present invention can be applied;
FIG. 2 illustrates a diagram for a typical wireless video system architecture, to which the present invention can be applied;
FIG. 3 illustrates a graphical representation of the received bit rate 5 versus the transmission rate offered for a WLAN connection; and
FIG. 4 illustrates a data flow diagram for a method for adaptive FEC for continuous video transmission between wireless networks, in accordance with the principles of the present invention.
Detailed Description of the Invention
The present invention is concerned with adaptive early error correction (FEC), in a preferred embodiment, for continuous video transmission between wireless networks. The present invention provides an adaptive FEC method and apparatus that improves the performance of continuous video transmission by dynamically adjusting the FEC intensity, based on the condition of the network. The number of redundant packets transmitted over a wireless network is optimized with ba20 if in the condition of the network. A feedback signal is used to inform the network condition to an adaptive FEC device on the transmitting side. The feedback signal can originate, but without being restricted, from the receiver, an intermediate node or the transmitter connection layer. Monitoring of the condition of the network can be carried out on the transmitting side, by accessing information from the transmitter's wireless hardware, such as retransmission attempts, or by using RTCP (Real Time Control Protocol) reports if RTP is used . The use of information on the transmitting side provides greater speed of response to changes in the network condition, since RTCP reports are not sent regularly in order to conserve network resources. However, RTCP reports include more information and could be used to more accurately estimate available network bandwidth. A combination of feedback messages can also be used. Based on the condition of the network, the adaptive FEC device decides how many redundant packets it will send. If the condition of the network is unsatisfactory, a greater number of redundant packets are sent than in the case where the condition of the network is satisfactory. It should be appreciated that, although the present invention is described in relation to FEC by packet level erasure, other types of packet level FEC can also be employed in accordance with the present invention, still maintaining the spirit and scope of the present invention.
The present description illustrates the principles of the embodiments of the present invention. Thus, those skilled in the art will recognize that it is possible to design various structures that, although not explicitly described or illustrated in the embodiments described in this document, incorporate the principles of the invention and are included within its spirit and scope.
All examples and conditional languages cited in this document are designed for pedagogical purposes, with the aim of helping the reader to understand the principles of the invention and the concepts contributed by the inventor to advance the technique, and must be interpreted without limitation in relation to said examples and conditions cited specifically.
In addition, all statements in this document that refer to principles, aspects and embodiments of the invention, as well as specific examples thereof, are designed to cover the structural and functional equivalents thereof. In addition, it is intended that such equivalents include both equivalents known at the time, and equivalents developed in the future, that is, any developed elements that perform the same function, regardless of the structure.
Therefore, for example, those skilled in the art will recognize that the block diagrams presented in this document represent conceptual views of the illustrative circuit system that incorporates the principles of the invention. Similarly, it will be appreciated that any flowcharts, data flow diagrams, state transition diagrams, pseudocodes, among others, represent various processes that can be substantially represented in computer-readable media and, therefore, executed by a computer or processor , whether such a computer or processor is explicitly illustrated or not.
The functions of the various elements presented in the figures can be provided by the use of dedicated hardware, as well as hardware capable of running software in association with the appropriate software. When provided by a processor, functions can be provided by a single dedicated processor, by a single shared processor, or by multiple individual processors, some of which can be shared. In addition, the explicit use of the term processor or controller should not be interpreted to refer exclusively to hardware capable of running software, and may implicitly include, unrestrictedly, hardware DSP (digital signal processor), ROM (read-only memory) for software storage, RAM (random access memory) and non-volatile storage.
Other hardware, conventional and / or custom, can also be included. Similarly, any switch illustrated in the figures is only conceptual. Its function can be performed through the operation of program logic, by dedicated logic, by the interaction of program control and dedicated logic, or even manually, the specific technique being freely chosen by the implementer, based on the most specific knowledge. of the context.
In the claims of this patent, any element expressed as a means to carry out a specific function is intended to cover any and all forms of carrying out that function, including, for example: a) a combination of circuit elements that perform that function; or b) software in any form, including, therefore, software stored in ROM memory (known as firmware), microcode, among others, combined with a circuit system proper to execute that software to perform the function. The invention, as defined by said claims, consists in the fact that the functionalities provided by the various reported means are combined and articulated in the manner required by the claims. The applicant, therefore, considers any means that can provide functionalities equivalent to those presented in this patent document.
Packet level wipe FEC is used to improve the reliability of wireless connections. Deletion is easier to deal with, since the exact location of the error is known. An erasure FEC scheme (n, k) encodes k source packets into n (n> k) packets. The encoding is such that any subset consisting of k packets is sufficient to reconstruct the source data.
Turning to FIG. 1, an illustrative encoding / decoding FEC process is generally indicated by reference number 100. the source packets (k original packets) 110 are fed to encoder 120, and packets 130 are produced by encoder 120. The n packets 130 include encoded data corresponding to the k packets 131, as well as the redundant packets 132 (i.e., the shaded blocks in FIG. 1). Interleaving over a series of FEC packets can be used to improve the performance of error correction in a series of FEC blocks. Decoder 140 decodes the n packets (which include the original k packets 110 and redundant packets) to obtain reconstructed data 150 (which is the same as the original k packets 110).
The wireless packet loss rate fluctuates with time, network condition, network load, and so on. Therefore, an early and adaptive error control scheme would be of great benefit to adjust the amount of redundancy transmitted by the channel. An anticipatory and adaptive error correction method and apparatus based on feedback is provided. If the network conditions are satisfactory, there is no need to send a large number of redundant packets. In contrast, when the packet loss rate is high (above a predetermined threshold), then more redundant packets are transmitted.
Turning to FIG. 2, a typical wireless video system architecture is generally indicated by reference number 200. The transmitting side (which includes elements 205, 210, 215, 220, 225 and 230) is the FEC protected video source, which can be content stored or transmitted in real time. The wireless video system architecture 200 includes a video storage 205 that has an output connected, in signal communication, to an input of an FEC 210 encoder. Optionally, a video capture unit 215 that has an output connected in signal communication to an input of a video encoder 220 which, in turn, includes an output connected in signal communication to the input of the FEC 210 encoder, can be used instead of 205 video storage. An encoder output
FEC 210 is connected in signal communication to a first input of a temporary storage 255. An output of temporary storage 225 is connected in signal communication to an input of a wireless network interface 230. A first output of the network interface wireless 230 is connected in signal communication to a wireless connection (also called a wireless network in this document) 235. A first and a second input of an adaptive FEC device 240 are respectively connected in signal communication to a second output of the wireless network interface 230 and to the wireless connection 235. An output of the FEC device 240 is connected in signal communication to a second entry of temporary storage 225. A receiver 245 is connected in signal communication to wireless connection 235.
The transmitter side 210 FEC encoder encodes the packets. Each package includes an integer number of macroblocks and has a fixed number of bytes. Then, the transmitting side packages the video data into the RTP / UDP Protocol (Real Time Transport Protocol / User Datagram Protocol) before being transmitted to wireless network 235 over wireless interface 230.
The transmitting side transmits all original packets continuously. The adaptive FEC block decides the number of redundant packets to be sent based on one or more feedback messages (hereinafter feedback message). The feedback message could originate from the receiving side and is transmitted to the transmitter by RTCP, or it can be obtained from the transmitter's wireless relay information. The wireless relay information calculates the number of times a packet is retransmitted, and could be used as an indicator of the condition of the network. An effective adaptive approach could use both information with RTCP to provide one more long-term idea of the condition of the network, while the information from the transmitting side could be used to generate rapid adaptation to the conditions of the network.
The adaptive FEC device 240 decides the number of packets to be sent based on the feedback message. Several alternative techniques can be used to determine the number of packages to be sent. For example, an embodiment of the present invention employs an increase / decrease function. In accordance with the principles of this embodiment, a satisfactory feedback message reduces the redundant packets to be sent by 1 to 0; otherwise, the number of redundant packages is increased by 1 to nk packages. To obtain a good adaptation rate, a large value for nk must be used.
In another alternative embodiment, an adjustment can be made using the RTCP receiver report. In particular, the lost fraction and cumulative number of lost packets fields in the RTCP transmitter report can be used for adjustments. These fields represent the number of packets lost since the last report of the receiver and the total number of packets lost since the beginning of the transmission, respectively.
For many 801.11 virtual WLAN (Wireless Local Area Network) connections, the effective transmission rate stabilizes at a constant value at some point, and in some cases, it actually decreases as the transmitting device tries to send more data over the connection. '. 'This is illustrated in FIG. 3, where a graphical representation of the received bit rate versus transmission rate offered for a WLAN connection is generally indicated by reference number 300.
If a video transmitter (included in the wireless network interface 230) is sending data at a rate at which the received rate increases as the offered transmission rate increases, then the FEC will improve the actual amount of information received. However, if the video transmitter tries to send more data when operating on the flat part of the curve, or in an even worse situation, on the decreasing part, then the FEC will not help and may in fact cause less video information to be received. For this reason, it is important that the video transmitter knows in which part of the curve of FIG. 3 it is actually operating. If it is operating on the decreasing part of the curve, then it should not increase the amount of FEC data and should try to improve performance in some other way (for example, by reducing the bit rate) so that the operation skips to the part increasing curve. If it is already operating on the growing part of the curve, then the video transmitter can add extra FEC information and have good results.
One way for the video transmitter to know if it is on the curve would be to use the feedback (for example, an RTCP report) from the receiver 245 or the relay information from the wireless transmitter. If the video receiver 245 receives a lower packet rate as soon as the FEC is added, then the transmitter is operating on the decreasing part of the curve. If receiver 245 receives a higher packet rate as soon as the FEC is added, then Ό the transmitter is operating on the growing part of the curve. This information would already be available to the video transmitter if it was already receiving information about the lost packets through some feedback path. Alternatively, the wireless transmitter's MAC (Media Access Control) level relay information could be used to estimate the number of packets lost, as already described.
Turning to FIG. 4, a method for adaptive FEC for continuous video transmission between wireless networks is generally indicated by reference number 400.
A function block 405 encodes a video stream to generate fixed size video packets (for example, MPEG2 transport packets), and passes control to a function block 410. In function block 405, the number of redundant packets to be sent (hereinafter also represented by variable X) is equal to zero (0).
Function block 410 encodes each source packet k using the erase code FEC to generate n packets with nk redundant packets, and then passes control to a function block 415. Function block 415 sends the first k packets of source and passes control to decision block 420. Decision block 420 evaluates and determines the condition of the network. If the network condition is good (that is, above a predetermined threshold), then the control passes to a function block 425. Otherwise, if the condition of the network is unsatisfactory (that is, below the predetermined threshold), then the control passes to a decision block 430.
Function block 425 sends X = max {Xl, 0} redundant packets, and returns control to function block 410. That is, function block 425 sends a redundant packet less than the number sent before, going down up to a lower limit of zero redundant packets. Decision block 430 determines the region of operation of the video transmitter in relation to the bit rate received versus the transmission rate offered (the curve shown in FIG. 3). In particular, decision block 430 determines whether the transmitter is operating in a region of increasing the curve of FIG. 3 or in a region without increasing the curve, and then the control passes to a decision block 440 that sends X redundant packets and passes the control back to function block 410. Otherwise, if the transmitter is operating in a region of increasing the curve, then the control passes to a function block 450 that sends X = min (X + l, nk) redundant packets, and passes the control back to the control block. function 410. That is, function block 450 sends a redundant packet more than the number sent previously, up to an upper limit of (nk) redundant packets. 0 return to function block 410 through function 425, 440 and 450 allows the adaptation of the number of redundant packets sent based on the condition of the network.
These and other aspects and advantages of the present invention can be easily confirmed by those skilled in the relevant art based on the teachings in this patent document. It should be understood that the teachings of the present invention can be implemented in various forms of hardware, software, ROM storage software (firmware), processors for specific use or combinations thereof.
Most preferably, the teachings of the present invention are implemented as a combination of hardware and software. In addition, the software is preferably implemented as an application program tangibly incorporated into a program storage unit. The application program can be transferred to, and executed by, a machine that comprises any suitable architecture. Preferably, the machine is implemented on a computer platform with hardware, such as one or more central processing units (CPU), a random access memory (RAM) and input / output (I / O) interfaces. The computer platform may also include an operating system and microinstruction code. The various processes and functions described in this patent document can be part of the microinstruction code or part of the application program, or some combination of these, which can be performed by a CPU. In addition, several other peripheral units can be connected to the computer platform, such as an additional data storage unit and a printing unit.
It should also be understood that, since some of the components and methods constituting the described system are preferably implemented in software, the actual connections between the system components or the process function blocks may differ, depending on the way in which the pre16 this invention is conceived. Considering the teachings given here, those skilled in the pertinent technique will be able to contemplate the described or similar implementations or configurations of the present invention.
Although the illustrative embodiments have been described in this patent document with reference to the accompanying drawings, it should be understood that the present invention is not limited to such exact embodiments and that several changes and modifications can be made to this by those versed in the relevant technique, without diverging the scope or spirit of the present invention. All such changes and modifications are intended to be included within the scope of the present invention, as set out in the appended claims.
9 members in 6 offices
Priority claims2
| Document | Office | Kind | Date |
|---|---|---|---|
| 63248904 | United States of America | P | |
| 2005020928 | United States of America | W |
Members9
| Document | Office | Kind | |
|---|---|---|---|
| WO2006060036A1 | World Intellectual Property Organization (WIPO) | A1 | |
| EP1817859A1 | European Patent Office (EPO) | A1 | |
| CN101061659A | China | A | |
| US2008134005A1 | United States of America | A1 | |
| JP2008522545A | Japan | A | |
| BRPI0516632AThis record | Brazil | A | |
| US8015474B2 | United States of America | B2 | |
| JP5425397B2 | Japan | B2 | |
| CN101061659B | China | B |
6 legal events, as the office reported them to INPADOC
Over the term
Point at a mark for the eventEvents
| Event | Code | |
|---|---|---|
| Requested transfer of rights approvedB25A | B25A | |
| Requested change of headquarter approvedB25G | B25G | |
| Requested change of headquarter approvedB25G | B25G | |
| Appeal against refusal [chapter 12.2 patent gazette]AppealB12B | B12B | |
| Patent application refused [chapter 9.2 patent gazette]B09B | B09B | |
| Application suspended after technical examination (opinion) [chapter 7.1 patent gazette]B07A | B07A |
Numbers
- Application
- 5166322
Titles2
- Portuguese
- correção de erros antecipada e adaptativa
- English
- early and adaptive error correction
Classification
- CPC, 1
- H04L1/0009
- IPC, 1
- H04L1 00