Method and communication station for transmitting data

Method for transmitting data and communication station

The present invention relates to a method for transmitting data in error monitoring mode through a parallel interface of a multi-hop communication system with the characteristics of the preamble of claim 1, or to a communication station implementing such a method.

In a multi-hop communication system (also referred to as a Multi-Hop communication system), data is transmitted from a transmitting station to the nearest receiving station either directly through an intermediate station or relay station or through multiple intermediate stations or relay stations. In addition to transmitting data through the only relay station that is transferred, data can also be transmitted through multiple relay stations connected back and forth, which is also called multi-hop. In addition, especially in a shared wave network (SFN: Single Frequency Network) communication system, one and the same type of signal and thus one and the same type of data can be received by multiple relay stations at the same time or with little time shift. Ground, that is, simultaneously or fairly shortly shifted in time and transmitted directly to the receiving station or to another relay station in the same frequency manner. Here, a pre-emphasis method or a de-emphasis method can be used in the relay station to improve efficiency. In order to ensure error-free data transmission, from this type or other communication systems, known error identification methods and error correction methods are used for themselves, such as automatic request for repeated transmission of original or updated data packets (ARQ : Automatically request retransmission). It is also known to use a so-called cyclic redundancy check (CRC: Cyclic Redundancy Check). Here, these methods can be re-applied for every single transmission, that is, for every transmission from a transmitting station to an adjacent relay station, every transmission from one relay station to another relay station, and from one relay station to another. Each transmission from the relay station to the receiving station. Although these measures ensure that the data reaches the receiving station through as many paths as possible without errors as much as possible, the disadvantage is that the calculation and time costs associated with this are high. In addition, the high energy consumption is also related to this method measure, because on the one hand, unpacking, decoding and checking the received data in the relay station, as well as requesting re-delivery or re-encoding and forwarding, all consume energy, and finally repeat the transmission. The retransmitted data packets also consume energy.

The task of the present invention is to improve the method to transmit data in error monitoring mode through the parallel interface of the multi-hop communication system, especially the method to improve the processing cost of the entire system, and to recommend the use of a communication station that implements such a method.

This task can be solved by the feature of claim 1, the method of transmitting data in error monitoring mode through the parallel interface of the multi-hop communication system, or a communication station with the feature of claim 9.

The preferred embodiments are the content of the dependent claims.

By only the receiving station, that is, the last station in the transmission chain, generating a confirmation or request for re-transmission of data, this station must also monitor only the received data with the required reception quality. When identifying the receiving quality that meets the requirements, the station can only transmit an acknowledgement or request thus generated in the direction of the station that originally transmitted the data. In the simplest case, the intermediately connected relay station is only used to transfer the received data or transfer the received confirmation or request. In this simple case, the check for transferring the received data in the relay station can be eliminated accordingly, which makes fast transfer and less energy consumption possible.

A relay station that transfers the received data, checks that the reception quality is insufficient, and does not transfer or transfer the data related to this, or maintain or disconnect the data communication connection according to the reception quality, although the relay station needs energy and needs Check the time to receive the data, but finally save energy by interrupting the transfer and requesting to retransmit the data. Since the originally transmitted data is transmitted through many parallel data paths in this type of communication system, there is a high enough probability that in the case of data loss on the transmission path and subsequent implementation of the data path In the case of deactivation, although the original data passes through at least one or more other parallel transmission paths, it still reaches the expected destination station or receiving station. Therefore, a communication system or a method measure is preferred in which data is only transmitted through a relay station that meets the requirements well or receives the data in an error-free manner sufficient to meet the requirements.

When the preferred relay station independently judges whether the transferred data has a sufficiently good quality for the transfer, a method is particularly preferred during this period, in which the information of the relay station on the parallel transmission path is also considered for the judgment. If a relay station on the parallel path informs that it can transfer the received data in a good or high-quality switching way for transmission, then the parallel relay station that informs this does not need to perform additional transmission. It may even be bad. Data received. This is when parallel data paths cross each other or each relay station can receive the transferred data of other relay stations in its surrounding environment.

It is preferable to use many known error correction methods or error identification methods in the relay station, among which this method is only used to identify the quality of the received data to be transferred, but not to identify the retransmission in the case of poor reception quality request.

It is particularly preferred to use this type of method in a communication system, in which different transmitting and receiving stations and relay stations communicate with each other on a single frequency. These conditions especially exist in a decentralized, that is, self-built communication network, such as these conditions are typical for specialized communication systems.

In the receiving station at the receiving end, the data received in parallel and superimposed with each other through different parallel paths are superimposed and jointly processed in a preferred manner, so that another quality improvement can be obtained through statistical average composition and so on.

Especially for condition-related transfer data in the relay station, a high total data rate, that is, a high retransmission quality, can be obtained at the receiving end. The way is that the data received by the receiving end can be notified by the receiving end. The overall quality has improved.

The communication station implementing such a method may be a transmitting station, a receiving station or a relay station, but it may also have two or all three functions in a combined manner. In addition to receiving, such a communication station has a transmitting device according to its purpose and an analysis device. The analysis device may be a component of the station's own control device and is designed to analyze the received data according to its reception quality.

Hereinafter, an embodiment and improvement scheme described for this will be described in detail with reference to the accompanying drawings. In the figure: Figure 1 shows in the form of a block diagram a communication system with a plurality of stations communicating through parallel data communication connections, and Figure 2 shows in the form of a block diagram the processing of the transferred data in the relay station Different ways.

As can be seen from Fig. 1, an example communication system MHSFN has many stations communicating with each other. For example, as a communication system, a multi-segment or multi-hop (MH) communication system is represented, and the multi-segment or multi-hop (MH) communication system is configured as a shared wave radio network (SFN: Single Frequency Network). However, transmission on other communication systems, especially transmission on dedicated communication systems, is possible.

A situation is shown in which a transmitting station SS transmits data D to a receiving station RS. Here, it is assumed that the distance between a transmitting station SS and a receiving station RS is so large that direct transmission between these two stations through a direct communication connection is impossible. The transmitting station SS transmits its data D to different transfer stations through multiple communication interfaces V11, V12, V13, and these different transfer stations are referred to as relay stations HS1, HS2, HS3 below for the sake of simple distinction. The relay stations HS1, HS2, and HS3, for example, can identify the data header (header) of the received data packet, referring to the received data D that needs to be transferred, and the received data D according to the destination station The direction is transferred according to the direction of the receiving station through other communication interfaces V21 and V23. Preferably, the communication interfaces V11, V12, V13, V21, and V23 are wireless interfaces, and these interfaces all work with the same or unique frequency. In the case that the receiving station RS is already within the transmission range of the relay stations HS1 and HS3, the received data D to be transferred can be directly transmitted to the receiving station RS. In other cases, the transmission can be realized through other intermediately connected relay stations.

After receiving the data D, the receiving station RS checks whether it is sufficient to receive these data without errors. For the inspection, common methods of error recognition and correction, such as ARQ and/or CRC, are used. According to such an analysis, the receiving station RS transmits an acknowledgment about the reception quality sufficient to meet the requirements, and/or transmits a request for retransmission or retransmission of the originally transmitted data D in the direction of the original transmitting station SS. The confirmation ACK or request can be retransmitted through the direct communication connection or multiple parallel communication connections V21, V11, V23, V13, V22, V12 in the case of relay stations HS1, HS2, and HS3. The transmitting station SS delivers new data D or new data packets according to the acknowledgement ACK and the request below, or prompts repeated delivery and selectively updates the original data to be delivered.

According to the preferred embodiment, the data D received for the transfer in the relay stations HS1, HS2, HS3 in a preferred manner cannot simply be transferred without checking, but should be based on the received quality or data before transfer Quality is inspected. If the relay station HS2 determines that the data quality of the data D received by the relay does not meet the requirements, or there is an error in the reception of these data D, the relay station HS2 does not establish a communication connection V22 for the relay received data D. As a result, the corresponding data paths V12 and V22 are interrupted, and the establishment of the data paths V12 and V22 is originally from the transmitting station SS through the second relay station HS2 to the receiving station RS. In particular, the second relay station HS2 also causes the original data D not to be retransmitted or updated.

In the relay stations HS1-HS3 that are transferred, in addition to the receiving device R and the transmitting device S, as well as the control devices and memory that are usually required for operation, devices and functions for checking and transferring received data are also provided accordingly. In particular, an analysis device A is provided for this, which is a component of the central control device of the relay stations HS1-HS3.

Other equipment and/or functions are used in a preferred manner to implement pre-emphasis or de-emphasis methods, by which, for example, the superimposition of the designed signal can reach the receiving station RS and optionally other relay stations for relay. For example, using methods known per se, such as phase or equal gain, maximum ratio or selective distortion. There are also mergers or expansions and other pre-emphasis techniques are possible.

According to another embodiment, it is also possible to communicate with each other using different relay stations HS2, HS3. Communication is also possible via a corresponding interface VH, which can preferably be configured as a wireless interface, but in principle can also be configured as a line-connected interface. Therefore, it is possible to transmit information about the data D received by the transfer or about its reception quality. In this way, it is possible to make the third relay station HS3 transmit this fact to the second relay station HS with a good reception quality after receiving the data D, and the second relay station HS receives the same data D in parallel as a parallel station, but This is received with very poor reception quality. In such a situation, the relay station HS can prevent the transfer of the transferred data D with poor reception quality, because the same data D with better transfer quality can be transmitted through the parallel data path SS-HS3-RS .

Generally speaking, the data received by the transfer can be processed before transfer in the relay stations HS1-HS3. Here, the type of continued processing and forwarding or forwarding can be lower than different parameters. For example, the signal-to-noise ratio (SNR) can be analyzed and calculated at the input terminals of the relay stations HS1-HS3 in the transfer. It is also possible to determine the number of correction bits in the Viterbi decoder, or to consider the result of the cyclic redundancy check CRC. As a processing technique, a method of equalizing and amplifying the received signal without performing another additional demodulation is particularly preferred. In the relay stations HS1-HS3 that check and transfer the received data, the received data D is demodulated and decoded in an appropriate manner so that actual analysis can be carried out. Not only the analyzed data D or data packet is re-encoded and modulated, and then the implementation of switching is possible, and the data D received by the original switching is stored in the temporary memory, so that if the doubled data group is being demodulated, After decoding and analysis, it is enough to be regarded as a transfer, and then transfer from the register in an unchanged manner. Such an implementation scheme is also possible. When the station receiving the data D is not the destination station but only a relay station, the method of retransmitting data packets that are erroneous or insufficient to receive can be deactivated in a preferred manner.

In the range of forwarding or switching, in addition to re-encoding and modulating data D or data packets, pre-emphasis may also be performed. In particular, after de-emphasis, amplification and even pre-emphasis, the received signal or received data D can be switched.

In principle, it is possible not only in a centralized network but also in a distributed or self-built network. The exchange of the parameters mentioned at the beginning between individual stations, in particular between relay stations on data paths parallel to each other, can be used particularly preferably, as described at the beginning of the article. However, it is also possible to use only the parameters used in the own station for analysis, for example, by means of error identification and correction methods known per se. Here, the use of the error correction method can be limited to the error identification part in the case of the relay station, where the error correction part is only used when no retransmission is required for this, but the data is transmitted through a sufficient number of parallel The data communication connection can be guaranteed. The same situation also applies to the error identification method, and the error identification method is preferably limited to error identification when there is a relay station, wherein the corresponding error identification notification should be prevented.

In the case of communication between adjacent stations, especially between the relay stations HS2 and HS3, on the one hand, only the analysis results can be directly transmitted to the adjacent stations, but it is also possible to negotiate between such adjacent stations. Or negotiate the analysis result or the calculation result, so that the neighboring station can determine which station HS3 negotiated to transfer the data in order to end this type of negotiation.

Figure 2 is used to graphically illustrate different modifications of the illustrated embodiment. Here, the focus is on the structure of the analysis calculation method. In simple terms, it can be assumed that, for example, only a single parameter is used, which is the result of a cyclic redundancy test. In addition, in a simple example, it is based on the complete demodulation and decoding of the signal received by the intermediate station or the relay station HS1-HS3. Here, the 2-hop SFN communication system is based on an error correction method in which an end-to-end communication connection of error correction ARQ is implemented. Error correction, as it is already known for a single communication connection, can be selected according to the scheme described now. As a result, the originating station SS does not receive an acknowledgement for the data or data packet, and the data or data packet is correctly received by the relay stations HS1-HS3 in transit. Accordingly, the safety device for the first jump is not separated. Only the receiving station RS confirms that the packet is received correctly, so that in the absence of an acknowledgment, the transmitting station SS repeatedly transmits a packet with a lack of reception confirmation.

For the relay station HS in transit, there are various possibilities for processing data D or data packets. According to a particularly simple embodiment a), an unconditional handover can be carried out in the relay station HS. Here, it may happen that the data packet received by the transfer has an error or the signal-to-noise ratio of the transferred signal is poor. In this case, the calculation parameters and so on are eliminated.

Therefore, it is preferable to transfer b) the received data D in conjunction with or related to the condition. These conditions can be analyzed and calculated independently of each other in a single different parallel relay station HS or on the basis of information from all or a plurality of relay stations HS2, HS3 connected to each other. Correspondingly, there are two improved schemes. In the simpler case c), only the intra-station analysis of the transferred data D is performed. If the analysis data has good enough data quality, it can prompt the transfer to the direction of the receiving station RS. If the data quality does not meet the requirements, it will prevent the transfer to the direction of the receiving station RS. It is also possible to stop answering the confirmation or request retransmission in a preferred manner.

According to another embodiment d), the communication according to the second and third relay stations HS2, HS3 can be carried out, wherein at least one of the second relay stations HS2 accesses the information of at least another third relay station HS3 in order to transfer according to its The situation is judged based on the possibility that the data D cannot be received optimally.

In a surprising way, it is even preferred to unconditionally transfer a) the data D is already irrelevant to the analysis and therefore irrelevant to the required or unqualified reception quality in the relay station HS. If all data paths SS-HS1-RS; SS-HS2-RS; SS-HS3-RS have approximately the same average packet error rate PER0 as the basis, then the total number of K relay stations set up in parallel with each other is exactly n The probability that a relay station can correctly receive a transmitted data packet can form a formula as follows: p(n)=Kn·(1-PER0)n·PER0K-n.]]>Correctly receive and forward accordingly The average number of relay stations for packet or data is calculated as follows; E(n)=Σn=0Kn·p(n)(1-PER0)·K.]]>When all K intermediate stations turn unconditionally During the joint transmission in the SFN communication system during connection, in the case of condition-related switching, that is, in the case of analyzing the reception quality of the received data D in the relay stations HS1-HS3 according to the preferred embodiment, only the data D passes through A small number of data paths SS-HS1-RS; SS-HS3-RS reach the receiving station. Therefore, in the case of condition-related transfer, the received power of the receiving station RS may be smaller than that in the case of unconditionally transferring data D through all relay stations. However, in the case that the transfer is partially blocked, the data D received by the receiving station RS has a higher data quality or a lower signal-to-noise ratio, so that it is possible that all the data quality improvements are recorded.