WO2002032040A1

WO2002032040A1 - Improvement in bandwidth efficiency in packet-oriented transmission with forward error correction

Info

Publication number: WO2002032040A1
Application number: PCT/DE2001/003831
Authority: WO
Inventors: Frank Burkert; Thi Min Ha Nguyen; Günther LIEBL
Original assignee: Siemens Aktiengesellschaft
Priority date: 2000-10-09
Filing date: 2001-10-05
Publication date: 2002-04-18

Abstract

Data (D) in a number of data packets (DP) for transmission are transmitted data packet by data packet. Each data packet is thus firstly segmented (1) into individual data segments (DS) and coded (2; C) with an error-recognising and then a powerful error-correcting code. The transmission then begins with incremental transmission (3) of the coded, segmented data (DS1...DSn) by means of the data channel (DK). As soon as the receiver unit (E) can decode (4; DC) the data packet (DP), using the data segments already received in an error-free manner, the above informs the transmitter unit (S), by means of the reply channel (AK), in the form of an acknowledgement (ACK). If the transmitter unit receives the ACK message, said transmitter ceases the current transmission and begins the transmission of the next data packet.

Description

description

Improve bandwidth efficiency in packet-oriented transmission with forward error correction

The invention relates to a method for the packet-oriented transmission of data from a transmitting unit to a receiving unit via a transmission medium with a data channel and a response channel with the following method steps:

- segmentation of a data packet to be transmitted into several data segments,

Redundancy generation by coding the data segments with an error-detecting code and / or an error-correcting code,

- Transfer of the coded data segments from the transmitter unit to the receiver unit in several steps by incremental transmission of successive coded data segments via the data channel.

Packet-oriented transmission of data generally results in packet loss for a variety of reasons. In packet-oriented fixed networks, packet losses are mainly caused by overload at network nodes. This happens, for example, as a result of buffer overflows and queue overflows in data packet switches or routers. A router evaluates the addressing information contained in the data packets and uses routing tables to determine the cheapest further route. This information is used to decide what will continue to happen to the data packet.

In the case of mobile transmission channels (e.g. packet switched odes in the Global System for Mobile Communication GSM, General Packet Radio Service GPRS or Universal Mobile Telecommunications System UMTS), the transmitted data is greatly reduced due to atmospheric interference and multipath propagation. disturbs. Due to the multipath propagation, a transmitted pulse generates several echoes. The superimposition of several such signal components or multi-way components with a respective phase shift compared to the direct propagation path leads to erasures which cause the so-called fast fading. These and other multipath fading phenomena lead to considerable fluctuations in the reception field strength. In addition to frequency-selective fading phenomena, there is also a temporal dispersion, with the result that individual symbols of the transmitted data “smear” over the part over several symbol durations and bit errors occur in digital transmission data.

The currently most widespread transmission protocols at the transport level (layer or layer 4 of the OSI reference model), namely the user datagram protocol UDP and the transmission control protocol TCP, react very critically to such bit errors in received data packets.

TCP is a connection-oriented transport protocol that enables a logical full-duplex point-to-point connection. It ensures that data is transmitted correctly and in the desired order over an underlying IP network. It extends the underlying IP (Internet Protocol) with functions for data backup and connection control.

As soon as a bit error within a packet is detected by an error-detecting code, the affected packet is discarded or deleted (erasure). In other words, packet loss also occurs. So-called reliable transport protocols such as TCP use repeat mechanisms (Automatic Repeat Request Procedure) to be able to safely transport lost or discarded packets to the recipient despite the faulty channels. Incorrect or lost data will be requested from the sender again. This is however, this is associated with a very considerable increase in the transmission delay (delay), which, however, cannot be tolerated by many applications (eg communication applications).

Unreliable transport protocols such as e.g. UDP used. Compared to TCP, which is used much more frequently, UDP does not recognize and correct errors. However, UDP works faster and has a smaller header, which is why the ratio of the number of user data (in bits) to the data packet length (in bits) is better. UDP is more suitable for applications that send short messages and can repeat them completely if necessary, or for applications that must be carried out in real time (voice or video transmission).

The entire error correction is therefore carried out within the application. This affects not only bit errors, but also the total loss of data packets, since routers immediately discard UDP datagrams when there is a high network load. The application can for special applications, for example in Ech ^'Ttime area, higher in the error detection and error correction of further layers special protocols are supported, such as the RTP (Real-time Protocol). The basic principle of RTP is the use of forward error control. This is made possible by an extended header that contains additional information. These are, for example, the type of user data transmitted (voice, image data, etc.) or the time of generation of the data, which makes it easier to put the data in a certain correct order or to discard them after a certain time.

However, due to the necessity of repeating messages completely in the event of errors, the use of UDP in a network also requires larger bandwidths than TCP and requires more complicated bandwidth management by the network operator. Thus, UDP alone does not cause an increase in transmission delay or delay, but does not offer any mechanisms to compensate for packet losses. That is why there are intensive efforts to combine methods for forward error correction (FEC) and packet-oriented transmission with unreliable transport protocols such as UDP.

Ideally, the resulting methods should adapt to the properties of the transmission channel in order not to require more bandwidth than is absolutely necessary. This applies in particular to the transmission via mobile channels, since there the resource bandwidth is particularly valuable, i.e. is very expensive for the subscriber.

Conventionally, this adaptation of the error protection to the transmission channel is mainly realized by using hybrid ARQ methods. ARQ stands for Automatic Repeat Request and represents a method for data transmission in which a transmitting unit sends data and waits for the correct acknowledgment by the receiving unit. If necessary, the sending unit sends the data again. This process is repeated until the data has been transferred correctly. There are two main types of processes:

- Stop-and-Wait-ARQ for character-oriented protocols, in which waiting for each character to be acknowledged,

- Contmous-ARQ for bit-oriented protocols, in which the acknowledgment is regulated by a window mechanism, so that if the window size is correctly dimensioned, transmission can take place continuously (e.g. with High Level Data Link Control HDLC, a bit-oriented synchronous control protocol on layer 2 of the OSI). Reference model).

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The advantage of this method is that only as much redundancy is actually transmitted as is actually required. However, this known method also has serious disadvantages in the case of packet loss channels.

The return channel must guarantee secure transmission, i.e. ARQ processes must also be used there. This requires the implementation of complex protocol stacks (e.g. timers). Depending on the number of repetitions and the Rpund trip delay (the time between the sending of information by the sending unit and the arrival of a response from the receiving unit via the return channel), very high delays can be expected, especially in mobile transmission scenarios. In multimedia applications, such as Streaming Videc, this means that there must be a very large buffer in the receiver. This also leads to increased complexity in the receiving terminal.

The object of the present invention application is therefore to simplify the transmission compared to the known prior art and still achieve an adaptation to the transmission channel.

According to the present invention, this object is achieved in that the method described at the outset is developed further in that coded data segments with additional redundancy are transmitted incrementally by the transmission unit until the transmission unit either sends a message about the successful error-free via the response channel Decoding of the data packet to be transmitted is received by the receiving unit or until all redundancy of the coded data segments has been transmitted.

According to a first advantageous embodiment of the method according to the invention, the coding is carried out in such a way that useful data of a data packet to be transmitted are in successive

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desire if the error protection used is not sufficiently high. However, this can be largely avoided if the error-correcting code is selected in accordance with the long-term characteristics of the transmission channel, in particular the data channel, and the Bearer Services QoS parameter (Quality of Service, QoS).

In order to rule out the possibility of a total loss of information, according to a further advantageous embodiment of the method of the invention, the error-correcting code is selected on the basis of information of a long-term characteristic of the data channel such that there is adequate error protection even in the case of the poorest assumed transmission quality of the data channel.

This can be achieved, for example, with the help of the real-time control protocol (RTCP), which, as part of the RTP, evaluates various statistics about the current connection (error rate, delay, etc.) and thus enables a check of the QPS (not everyone) a high QcS enables itself).

A particularly advantageous embodiment of the invention uses a reed solo on code as the error-correcting code. Examples of such error-correcting codes can be found in the above-mentioned work by Lin, S./Costello, D.

According to the invention described above, a transmission unit or a reception unit can also be created to achieve the advantages mentioned, which have appropriate means for carrying out the method according to the invention for packet-oriented transmission of data.

Such transmitting units and receiving units can be used particularly advantageously in communication terminals or communication networks. The best results are achieved if transmission channels with the shortest possible round trip time are provided for a communication network.

A crucial distribution is that, in contrast to conventional ARQ methods, only a single reply (ACK) is required and not several. In addition, this response can be transmitted via a less complex reverse link or response channel. An additional ARQ procedure is therefore also not necessary for the response channel.

Further details and advantages of the invention result from an advantageous exemplary embodiment shown below and in connection with the figures. Elements with the same functionality are identified with the same reference symbols. In principle it shows:

1 shows a transmission and reception unit connected via a faulty transmission channel, FIG. 2 shows a block diagram of a transmission unit with the transmitter-side measures of the invention and

3 shows a block diagram of a receiving unit with the receiving measures of the invention.

The principle of the invention will now be illustrated using an exemplary embodiment. 1 shows the scenario of a transmission between a transmitting unit S and a receiving unit E via a disturbed transmission channel (indicated by a lightning-shaped one)

Arrow) with a data channel DK and a response channel AK. The response channel AK can be technically simpler than the data channel DK, which is indicated by the arrow DK which is thicker than AK.

A streaming multimedia application via a mobile packet loss channel DK (ie wi- CO co r KJ P- ¹ P- ¹ c-π ono Cn o Cn

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P Φ φ P φ TJ co Cϋ tr Cfl P TJ α υa 0 P- P d fr Ό P- d 0 ¹ P ¹ φ Cϋ d • Ω Φ dd tr 3 tö P P- d Φ rt P. P rt P- Φ P d N 3 φ tr d Φ d

Φ Cfl P- "TJ d Hl N α υ 3 3 φ P- Φ Φ rt fr P- Φ 0 PP α *» P s: Φ ≤ o Tl P: Φ P φ p- d 3 d Φ tr 13 d φ Cfl P "P d

O: ιP φ PP><σ ιP P- rt d rt tö P- L_l. T ^? ö ü rt Φ P- P. dd P ¹ 3 Cfl P- d 3 P- ^ P ^J d PP d Ω φ P. φ Pi rt φ PP TJ φ Cfl P α P- Hl d Φ P- Φ P rt Φ co φ α P rt d tr d Φ P- φ P. 7 ^? rt d rt d Φ φ d φ d rt P- - - φ d φ P ¹ φ P 1 P φ <P d Cfl d Φ co tr Φ φ Cϋ Φ Hi P- cn φ \ φ. d et ad t-3 P. d Φ φ d Ό P- o er d = N r ^? rt P P- Tl> rdd Cϋ φ tr N Φ 1 Ό Cfl rt ^ P cj P- Φ d O dd 3 Φ M d φ P p: P od Q Φ 1 P- P er 3 tr ≥! φ d Φ PNP rt d Hl Cfl P ¹ d tr P- n ü ^' Hi τι P- CΛ Φ fr φ 3 φ Φ 0 P "1 3 0 Φ fr Ö: φ Hi σ Cfl d Φ φ s CΛ P. - . cn * <! P- Φ tr P d er o CΛ P- Φ P σ dd P- CΛ φ Φ Ps ^? p>P> P "tV> 13 ä P ¹ rt Φ d rt et N s: d Hi ιP sQ rt rt φ d 0 Φ Ω d α P lO and others - P- & Φ co Φ d Φ d p. P- d 0- φ Cϋ Φ d H a P- PP Φ d P tr tr Φ ^ φ P dd PP d P- ds: 0 ü d rt dd rt rt P- d 0 CΛ

P- P- d 00 P ¹ P * co "* Φ P α υa rt α ιP p: P. TJ Ό d rt φ Φ P- Φ er 1

Cfl CΛ - -

- co s: Φ tr CΛ d φ P- tr Φ P P Φ P- d φ tr tr TJ s. Φ P- P- d Φ P d d P φ Φ d s: for inter alia d d d • Φ P P o α φ TJ P- P- d P- «a Φ d d rt P- Φ φ <l φ P 0 tr 0 d d

S CΛ P Φ P- rt P φ tr co S d φ Φ TJ d rt d P d d Φ 0 Φ Φ O: tr P

P "d CΛ d CΛ Φ P P- ^• ö 0 d P P- P- tr d and others Cfl p- rt P 3

CΛ rt Φ Φ d Cfl ιP <co P p- P. α d σ P- σ φ P ¹ CΛ P rt d P- d Φ α 3 tr fl Φ φ o? ^? dd Φ ιQ P 0 tr J Φ φ 0 CΛ σ P- φ <P α rt

Φ P- P. P Φ 0 P> tr 0> P σ Cϋ Hi d: rt er Φ sdd L Φ ngd er Φ d rt Φ ~> P- Hi 0- φ CΛ et P d φ Cϋ H- 0- dd ^ Cϋ dd et d Φ σ CΛ tr P- 3 3 ϋ Φ d Cfl Cfl dd CΛ tr P- Φ P- Φ rt C φ td TJ Cϋ Φ jy P '-_- d tr φ 0 d 3 ^ rt Ό Ό Φ rt d Φ Φ φ d tr! d P. p: P u3 0 OP ^J rt 3 Φ 3 P- tr P cn P- PT) P- d P- P- d φ NZ Φ Cϋ Φ d • Φ • φ Φ T dd Φ sQ TJ rt rt vp ^ r φ rt 3 Tl d P- P- Cϋ d 0 ^? 3 cn 3 H Cfl TJ d 0 P 13 NNP P- Φ cn Cϋ PP ¹ d φ o tr P- 0 φ d rt P ^J P φ o P α φ Cfl P ¹ Hl 0 φ Φ ^■ P 3 rt et co P d Φ 0 tr P ¹ d φ X _^

P 3 P φ O φ Φ P- P P- P- P ^J d P Φ PZ u P- 3 P- Φ rt Φ P d • 13 d. rt tr p. d ι P- tr Cfl Ω Ω P CΛ rt 0 ü Φ Cϋ Φ P rt Tl P- 0 and others OP

1 Φ Φ 1 d 3. -. Ω Φ 0 ^? tr P tr P- TJ cn P- 0 P- <1 rt s; , 0 Ω 13 Ω dead μ. CΛ P- Φ N tr N 0 Φ P- CΛ a- cn Cfl • do CΛ Q φ 0 ¹ P? S ^?

• <p: - P <P d • e P Φ Cϋ d 1 P Ω tr N p- φ Hi 0 Λ d CΛ and others 0 Ω Cϋ rt d tr co P- rt tö P- ¹ rt et PJ Ω tr φ 0 φ ü o φ l \ J P. o er rs ¹ et

Φ ιP Φ PP φ Φ • u P ¹ N • ~ t ^? φ P ^? Φ d 0 d P. P d Cϋ d N φ 3 tr N Cϋ

Cfl Φ d P ^J 3 d φ rt p: P- d rt p: rt 0 co 3 P- P * dd P- Φ et Λ rt P ¹ P φ α tö 0- dd P "tr d Ω • d P 0 p: P. rt P- Pi Z tr P "0 d Λ • tr α P- Cϋ ιP N o P tr Ω P rt N dd <! 0: Cϋ P- φ P α α 3 rt Φ Φ Ω d Φ ≤ P ιP co ti tr f H- Φ rt ia P> P. dd rt

Cfl uq P- -— _^ Φ + Φ p tr rt - P • P. d rt 0 rt O P- Φ Φ P "P Φ P Ω rt P 0 φ tö d P ¹ Cfl rt ≥! Φ d φ 0 d Φ dddd 1 {- • dd P. CO tr

Φ 0 0 CΛ - dd P- P- P sQ Cfl P- Φ Φ rt N d φ 0 Φ tr CΛ ιP o - 'o tr P rt φ 3 3 P Ω CΛ Φ c. 0 P ¹ σ d P- d 1 et Cfl 0 P P- 1 N α

3 rt CΛ P 1 ia 1 Cϋ P ¹ φ

• 1 1 1 co 1 • 1 1 1

The i-th code word CW in the transmission block is thus composed from top to bottom in FIG. 2 of the i-th byte of the payload part of each data segment DS1 to DSn, and is therefore systematic (1 = <i = <1).

The reason for this special type of coding is as follows: if a data segment DS1 to DSn of the transmission block is lost, then only a single symbol (here: 1 byte) is located in the same (known) position in all 1 code words CW1 to CW1 deleted. By means of known, Erasure

Decoding algorithms', this symbol can now be reconstructed separately in each code word CW1 to CW1 by means of the added redundancy R, and ultimately the content of the entire transmission block DS1 to DSn or DP. Due to the special property of RS codes, which are known to be `` maximum-distance-separable '^' , this type of reconstruction works as long as the number of lost data segments is less than or equal to the number of redundancy segments R or DSm + 1 to DSn ( in this case it is nm). This explanation may suffice to understand the following procedures.

After redundancy R has been added by coding 2 or C as described above, data segments DS1 to DSn are transmitted 3 in accordance with their sequence via data channel DK (from the view of the illustration in FIG. 2 'from top to bottom "). This is advantageous in such a way that data segments DS1 to DSm, which contain user data N, and only then such data segments DSm + 1 to DSn are transmitted with redundancy R. This can be done, for example, by means of a shift register SH into which a data segment is loaded and then sequentially output byte by byte over data channel DK until all 1 bytes of a data segment have been output, then the next data segment is loaded into the shift register and so on. co co MNP ¹ P ¹ cn O cn O cn O Cn rt et Φ α P z rt ≥; Cfl Hi H, P "M ua rt P? P- tr <Φ Φ P? Cfl P φ P cn p. Ö

Φ Φ d P- do Φ P Φ P- P d φ d Φ 3 d Φ o φ d Φ o P- tr Cϋ rt tr Ω Φ tr P d cn φ Hi dd Ω and others Φ d Φ P d P d, dd P "d er d P ¹ Φ Cfl tr d Φ tr α rt ia rt 13 tr 3 N P- P ¹ fr tr Hi ia P. § P ^J rt d Cfl d Φ ddd Φ

, -. P Cfl d PP Φ N Cfl o Ps ^? d O cn Φ φ P. os: CΛ d Hi P ^? Hl P P- S rt P- p. rt NP d PP? Φ d 0 Φ 0- d P d tr dddd Φ rt Φ P α er ö P P- rt od

• Φ 0 d Cϋ ded ua tr Φ d co u P "tr P ^J p: Hi ¹ TJ P- P - • φ rt tr P ua - d • P et Hi Φ 3 Φ d P rt Φ P dd P P- P. d Hi P- P rt P ¹ Φ P- and others Φ

• co P ¹ Cfl P ö Φ d P ¹ ω d Ω φ P ^J Φ Φ P. φ Cfl d Φ cn Hi P ^J d tr

Φ Φ t P "<l φ d rt and others P. fr <J fr rt and others d P- d Cfl 0 0- Hi d Φ α and others 3 P Φ α and others P Ω rt d Φ. -. Φ CΛ Φ o Φ • u P- 0: PP CΛ P d P- 0 and others 0

P 3 0

TJ dd P Φ P tr α N ddd P. 0 Φ φ tr d Φ Φ d 0 co

Cfl φ -S3 0 Φ • P- and others Φ P • Φ Hi co φ ω d Φ P. d and others co P. P ^? t Φ d Φ - α Φ Cfl P- P- α Φ d Cfl tö zd 0- rt d Cϋ d φ 3 Φ. P- P ^? P

, d et P- 1 Φ P- Ω Ω Cϋ Λ d • p- Hl and others d 3 σ CΛ d S Φ TJ 0 φ P d rt d et H3 d - ¹ d 3 N d P tr d PH P * ^ Φ ddddd 0 P cn

1 . -. 13 N φ P- ϋ 0 + z P z P- P. P P- d tö et P- rt P- φ PP ^J 13

X 3 0 P- O: Ω d P ¹ φ Cϋ d and others Φ Hi Φ Cϋ odd rt Φ dzd M cn d

1 P- 0 13 u> P? ad P ^J P- α d Φ d P p- 0 od P- N o Φ

3 rt P ^? 1 φ o rt ö d Φ rt T! P Φ d rt d Cfl CΛ P ¹ CΛ d 3 ö P- d P- N t Ω

- et d Φ 4- =. d Φ Φ P <j P- 3 13 φ Φ Ω Φ CΛ 13 Cfl P- Φ X tr

1 X P- d 1 0 Ω & 0 P P Ω α z P P- iQ tr Φ co rt φ P- Φ er P 3 ≥! 0 o tr • 0 0 and others - P ω rt Φ 3 fl P- P- P- P rt TJ d

Cϋ Λ d φ and others P 0 α N ö 0 Φ rt d P- Φ φ φ d P tr P- Ω TJ <P P.

P ^? - Ω P- ξ CΛ ≥; Φ α P Cϋ Φ - P di tr φ P P- NPPP fr

TJ d OP tr φ 3 P Φ 0 ä d Φ d 3 rt d Φ d P cn N Cfl Ps d Φ φ 1 d P 0 d P- d + Ω Φ P- cn 13 CΛ d co P- Φ rt φ Φ Cϋ P- rt Φ

3 pd Hi P- φ 0 ö M - d P du Hl Φ ^ 13 rt N d Φ ua Φ ö _^ er P φ d. d - rt Ω 0 O co Φ φ P and others P 0 rt and others Φ d CΛ <d

0 ^ _* tr M u P ^ M α co and others d 3 Cfl Ps ^? d P- P- d 0 φ P- Cϋ rt tr cn p- Φ Φ rt 3 3 P- d PP and others Φ P Cϋ Φ Φ Λ p- α N cn d N rt

P d P 3 13 α P- Φ tr rt P ^ d Φ d tr et d α rt d Φ N Φ rt P- z P d 0 P Hi od ia P Φ P- P ia d rt P ϋ Φ φ ia Cfl 0 P- • d cn • rt

N CΛ ^ d p: P- Φ P-- d rt α Φ Φ r-> ö Ω Φ and others cn rt P-

13 Φ Q. φ P 0 3 0 rt co rt P- d s: P. tr CΛ P φ d N Φ rt ö rt σ Λ

P d ϋ d d a Φ P Φ Φ 0 ^ d -, N 1 P. P- CΛ 0 P- Φ P d P rt

P? 3 α P P- φ d P ^J P and others d Φ 3 zo P- d ffi dd P and others rt P- ϋ CΛ Φ P ^J φ d 0 Φ 3 ö 1 P and others P- • o φ u & 0- Φ H d rt P- φ cn er φ P- φ ≥; φ Φ P td P Φ P 0 d φ φ rt tr d 3 Φ tr d Ω

- Λ P- 0 CΛ P- ddd rt P CΛ d P ¹ P. ö P- 0 d Φ Φ 13 tr rt cn tr

0 Φ tr

φ d rt Pi Φ Φ rt Φ Ω Cfl. φ P Φ 0 φ Pi P- d Hi Hi Φ cn Z Φ Φ cn Cϋ Φ d tr N or Φ d tr z co rt d ia CΛ o P "rt Φ p: 0 Cϋ φ ia 0

Φ 0 Φ P-. -. P- Φ d co co CΛ P Cϋ rt Φ 0 Φ. d tr 0 p: cn cn 3

0 N rt P φ P- P p. M rt 0- Φ 0 P ^J Φ 0 0 Λ> d and others P P- and rt Φ φ M and others 0 Φ et rt Φ 3 Φ P- and others P Pi Ω d 13 and others Cϋ O and others Φ Φ P- d N 0 p-

Φ <φ CΛ Cfl P- Φ d 13 dd 3 d and others 0 ^{^} Cfl P tr d 0 Φ Φ dd and others rt Φ et and others

P d ua d M d Hi ua φ Hl d Cϋ P ^? MN 0 _^ d 0 Hi Φ rt P ¹ P- Cϋ Φ d P tr Φ tr P- p: N Φ 0 0 • - - 3 Cϋ zd P- p- rt 0 z & Φ P- Φ: ≥! Ω dzu et 0 et tr P- E? Φ Φ 0 P- Ω <cn

P- σ Φ P- P- tr 0T Cϋ Φ Φ P α ϋ N P. d 3 d P- tr P- tr P- Cϋ Ω

P ω 0- et φ Φ Cϋ φ P- d α 3 Φ P z ü P 13 Φ Φ Φ Ω d tr et P- 13 Ω d P- d CΛ Φ CΛ rt σ • nd P. Pi Ö 0 P- and others tr

, P φ P P- fr Λ d φ t Pi os P- φ TJ d PPP rt P- Φ Φ O Hi d Cfl Φ rt ^ Q. Φ 3 P- φ Φ od - dn P CΛ d rt tö ddd rt σ Cfl ϋ co 0 tr 0 tr Φ tr CΛ <0 P a Φ Φ m p- Φ Φ

P- Cϋ. -. Cfl α 0 α tr 0 0 P- Cfl Φ Φ o P ^? CΛ P ^J α d P ^? Tl d er dd

Φ ia d Z d P- α P Φ 0 Φ α p ^j ia P ^J P ia Λ P- fr Ό 0 0 H ia 1.

3 1 Cϋ φ P rt P- 1 d 1 TJ er 3 0 Φ Φ P P 0 P- cn Φ P. c Φ? P- Ω $ 1 φ rt 1 α Φ d φ 1 0 and others d 1 1 Ω d ö Φ

1 Cfl - et d CΛ - P 0 Φ d tr ω P fl

1 1 φ 1 1 M 1 1! 1 rt

rr P ¹ P ¹ cn o cn o π

3 dr

P- Φ d d

P- rt

3 d

P- P φ and others d 0

Φ 0

0 and others

•

UJ z

P- d

P

0 α P- φ co φ d

CΛ rt

Φ

P ¹

Φ cn

P

hl

P d rt and others φ cn rt o

13

13 rt d d

3

P- rt

Claims

claims

1. Method for the packet-oriented transmission of data (D) from a transmitting unit (S) to a receiving unit (E) via a transmission medium with a data channel (DK) and a response channel (AK) with the following method steps:

- segmentation (1) of a data packet (DP) to be transmitted into several data segments (DSl ... DSm),

- Redundancy generation (R) by coding (2; C) the data segments (DS1 ... DS) with an error-detecting code and / or an error-correcting code,

- Transmission (3) of the coded data segments (DSl ... DSn) from the transmitter unit (S) to the receiver unit (E) in several steps (n) by incremental transmission of the coded data segments in succession via the data channel (DK), characterized in that Coded data segments (DS1 ... DSn) with additional redundancy (R) are sent incrementally by the sending unit (S) until the sending unit (S) either via the response channel (AK) a message (ACK) about the successful error-free decoding ( 4; DC) of the data packet (DP) to be transmitted is received by the receiving unit (E) or until all redundancy (R) of the coded data segments (DS1 ... DSn) has been transmitted.

2. The method for packet-oriented transmission of data according to claim 1, characterized in that the coding (2) is carried out in such a way that useful data (N) to be transmitted of a data packet (DP) are divided into successive data segments (DSl ... DSm) of the same length ( 1), which are supplemented by the respective redundancy symbols (R) of an error-correcting code for respective code words (CW1 ... CW1), the code words (CW1 ... CW1) being arranged for transmission in such a way that each code word (CW1 ... CW1) forms a column of all coded data segments (DS1 ... DSn) to be transmitted successively.

3. A method for packet-oriented transmission of data according to claim 1 or 2, characterized in that first such coded data segments (DSl ... DSm) are transmitted, which only contain user data of the data packet to be transmitted, before coded data segments (DSm + 1 ... DSn) are transmitted, which contain redundancy information (R).

4. The method for packet-oriented transmission of data according to claim 1, 2 or 3, characterized in that the error-correcting code is selected on the basis of information of a long-term characteristic of the data channel (DK) so that even with the worst-case transmission quality of the data channel (DK) a sufficient Error protection exists.

5. A method for packet-oriented transmission of data according to any one of the preceding claims, that a re-Solomon code (RS) is used as the error-correcting code.

6. Sending unit (S) for performing the method for packet-oriented transmission of data (D) according to one of the preceding claims.

7. receiving unit (E) for performing the method for packet-oriented transmission of data (D) according to one of the preceding claims 1 to 5.

8. Communication terminal with a transmitting unit (S) according to claim 6 and / or a receiving unit (E) according to claim 7.

9. Communication network with at least one transmitting unit (S) according to claim 6 and a plurality of receiving units (E) according to claim 7.

10. Communication network according to claim 9, so that transmission channels (DK, AK) are provided with the shortest possible round trip time.