WO2015149868A1 - Procédé et nœud pour améliorer les performances de taux d'erreurs sur la base d'informations d'en-tête de paquet - Google Patents

Procédé et nœud pour améliorer les performances de taux d'erreurs sur la base d'informations d'en-tête de paquet Download PDF

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Publication number
WO2015149868A1
WO2015149868A1 PCT/EP2014/056825 EP2014056825W WO2015149868A1 WO 2015149868 A1 WO2015149868 A1 WO 2015149868A1 EP 2014056825 W EP2014056825 W EP 2014056825W WO 2015149868 A1 WO2015149868 A1 WO 2015149868A1
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Prior art keywords
header
network node
data packet
information bits
ipv4
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PCT/EP2014/056825
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English (en)
Inventor
Krister Norlund
Anders Hansson
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Telefonaktiebolaget L M Ericsson (Publ)
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Priority to PCT/EP2014/056825 priority Critical patent/WO2015149868A1/fr
Publication of WO2015149868A1 publication Critical patent/WO2015149868A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
    • H04L1/0045—Arrangements at the receiver end
    • H04L1/0047—Decoding adapted to other signal detection operation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
    • H04L1/0056—Systems characterized by the type of code used
    • H04L1/0061—Error detection codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0078—Avoidance of errors by organising the transmitted data in a format specifically designed to deal with errors, e.g. location
    • H04L1/0079—Formats for control data

Definitions

  • Embodiments herein relate generally to a first network node and a method in the first network node. More particularly the embodiments herein relate to handling data packets in a communications system.
  • WCDMA Wideband Code Division Multiple Access
  • data is communicated across a wireless channel, i.e. from a transmitter to a receiver.
  • the wireless channel may be characterized by its impulse response, and there may also be thermal noise in the receiver of the data. Neither the wireless data nor the channel impulse response is known at the receiver side and the thermal noise may only be statistically described. Therefore, the receiver has to solve a joint optimization problem, i.e., it has to estimate the channel and decode the data jointly. This problem may have many possible candidate solutions and there would be little hope in selecting a candidate solution that corresponds to the transmitted data unless a known structure is introduced in the form of a channel code.
  • a channel code is associated with the physical layer, i.e. Layer 1 , and is used for correction and detection of errors in data transmissions.
  • Forward Error Correction (FEC) and Automatic Repeat- reQuest (ARQ) are two issues related to channel coding.
  • FEC relates to discovering and correction of errors
  • ARQ relates to discovery of errors and sending a resend request to the transmitter of the data.
  • the channel code is known at the receiver and in WCDMA it is specified in the 3rd Generation Partnership Project (3GPP) documentation.
  • the channel is not known and must be estimated at the receiver.
  • the WCDMA standard specifies transmission patterns of known symbols, also known as pilot symbols. Errors in the channel estimation process significantly deteriorate the performance of the decoding process, but even in the presence of a perfect channel estimation the performance of the decoder is limited due to the thermal noise. This, in turn, limits (i) the cell throughput, or (ii) the coverage, or (iii) the wireless device battery life, or (iv) combinations thereof.
  • An objective of embodiments herein is therefore to obviate at least one of the above disadvantages and to provide improved handling of data packets in a communications system.
  • the object is achieved by a method in a first network node for handling data packets in a communications system.
  • the first network node comprises a memory having stored on it at least part of a first header associated with a first data packet.
  • the first network node receives, from a second network node, a second data packet comprising a second header.
  • the first network node determines side information bits for the second data packet based on that at least part of the second header is assumed to be equal to or associated with the stored at least part of the first header.
  • the first network node performs at least one of channel estimation and decoding of the second data packet in which the side information bits for the second data packet are used as a priori information.
  • the object is achieved by a first network node for handling data packets in a communications system.
  • the first network node comprises a memory having stored on it at least part of a first header associated with a first data packet.
  • the first network node being adapted to receive, from a second network node, a second data packet comprising a second header.
  • the first network node is further adapted to determine side information bits for the second data packet based on that at least part of the second header is assumed to be equal to or associated with the stored at least part of the first header.
  • the first network node is adapted to perform at least one of channel estimation and decoding of the second data packet in which the side information bits for the second data packet are used as a priori information.
  • Embodiments herein afford many advantages, of which a non-exhaustive list of examples follows: One advantage of the embodiments herein is that they may provide higher cell throughput.
  • a further advantage of the embodiments herein is that they may increase the coverage of the first network node.
  • Another advantage of the embodiments herein may be that they prolong the battery life of a wireless device.
  • a further advantage of the embodiments herein is that they may lower the Bit Error Rate (BER).
  • BER Bit Error Rate
  • Fig. 1 is a schematic block diagram illustrating embodiments of a
  • Fig. 2a-2b are signaling diagrams illustrating embodiments of a method.
  • Fig. 3 is a schematic block diagram illustrating embodiments of internet two-way communication over a wireless link.
  • Fig. 4 is a signaling diagram illustrating embodiments of a method related to file upload.
  • Fig. 5 is a signaling diagram illustrating embodiments of a method related to
  • TCP Transmission Control Protocol
  • Fig. 6 is a flow chart illustrating embodiments of a method in a first network node.
  • Fig. 7 is a schematic block diagram illustrating embodiments of a first network node.
  • the embodiments herein are based on the fact that the header in the data traffic to and from an Internet host follows certain patterns.
  • a wireless device downloading a file from a file server using TCP.
  • the file is split up in TCP segments at the file server and each TCP segment is sent as individual Internet Protocol (IP) data packet to the wireless device.
  • IP Internet Protocol
  • Each TCP segment transmitted by the file server and received by the wireless device may trigger TCP acknowledge data packets sent back to the file server.
  • the TCP header and IP header of the TCP acknowledge data packet sent back to the file server may to a large extent comprise information that also was part of the TCP and IP header of the TCP segment sent from the file server to the wireless device.
  • the embodiments herein exploit this fact.
  • FIG. 1 depicts a communications system 100 in which embodiments herein may be implemented.
  • the communications network 100 may in some embodiments apply to one or more radio access technologies such as for example Long Term Evolution (LTE), LTE Advanced, WCDMA, Global System for Mobile Communications (GSM), or any other 3GPP radio access technology, or other access technologies such as e.g. Wireless Local Area Network (WLAN).
  • the communications system 100 comprises a first network node 101 configured to communicate with a second network node 105 over a channel 110.
  • the link 1 10 may be wired or wireless.
  • the channel 1 10 may also be referred to as a link.
  • the first network node 101 is a base station and the second network node 105 is a wireless device. In other embodiments, the first network node 101 is a wireless device and the second network node 105 is a base station. These different embodiments will be described in more detail later.
  • a base station may be for example an evolved Node B (eNB), a NodeB, a Radio Network Controller (RNC) or any other network unit capable of communicating over the wireless link 1 10 with a wireless device being present in a cell and being served by the base station.
  • eNB evolved Node B
  • RNC Radio Network Controller
  • a wireless device may be a device by which a subscriber may access services offered by an operator's network and services outside operator's network to which the operator's radio access network and core network provide access, e.g. access to the Internet.
  • the wireless device may be any wireless device, mobile or stationary, enabled to
  • the wireless device may be portable, pocket storable, hand held, computer comprised, or vehicle mounted devices, enabled to communicate voice and/or data, via the radio access network, with another entity, such as another wireless device or a server.
  • the channel 1 10 in the communications system 100 may be of any suitable kind and it may use any suitable protocol depending on type and level of layer (e.g. as indicated by the Open Systems Interconnection (OSI) model) as understood by the person skilled in the art.
  • OSI Open Systems Interconnection
  • FIG 2a illustrates an embodiment where a first data packet is sent from the first network node 101 to the second network node 105
  • figure 2b illustrates an embodiment where the first data packet is sent from the second network node 105 to the first network node 101.
  • time is illustrated by the vertical arrow on the left side of the diagram.
  • FIG. 2a illustrates a method which comprises the following steps, which steps may as well be carried out in another suitable order than described below.
  • Step 201 a
  • the first network node 101 transmits a first data packet to the second network node 105 over the wireless link 1 10.
  • the first data packet may be formatted according to a protocol.
  • the protocol may be TCP, IP, Real-time Transport Protocol (RTP), User Datagram Protocol (UDP) etc.
  • the first data packet comprises a first header.
  • the header may also be referred to as header information, control information, protocol information etc.
  • the header may be information necessary for delivery of payload data.
  • the header may be e.g. source and destination address, data type, data packet number, total number of data packets, error detecting codes, sequencing information etc.
  • the first data packet may comprise a first payload data.
  • the payload data may also be referred to as user data.
  • communications system 100 may achieve error detection and multiple hosts addressing.
  • a data packet may also be referred to as a frame, a block, a cell, a segment etc.
  • the first header may be located at any suitable location in the first data packet.
  • the first header may for example be located before the first payload data, the first header may be located after the first payload data, a part of the first header may be located before the first payload data and the remaining part of the first header may be located after the first payload data etc.
  • the first data packet may be a TCP data packet.
  • the TCP data packet comprises a TCP header which may be the first header and the TCP data which is the payload data.
  • the TCP header comprises a plurality of parameters, such as e.g. source port number, destination port number, sequence number, acknowledgement number, data offset, reserved bits, flags, window size, checksum, urgent pointer etc.
  • the first data packet may be a UDP data packet.
  • the UDP data packet comprises a UDP header which may be the first header and UDP data which is the payload data.
  • the UDP header comprises a plurality of parameters, such as source port number, destination port number, length and checksum.
  • the second network node 105 may perform processing of the first data packet upon receipt (not shown). Such processing may be for example decoding and channel estimation.
  • the first data packet may be received by the first network node 101 from the Internet or the internet host before transmission to the second network node 105 in step 201 a when the first network node 101 is a base station and the second network node 105 is a wireless device.
  • the first data packet is to be further transmitted to the Internet by the second network node 105 when the first network node 101 is a wireless device and the second network node 105 is a base station.
  • Step 202a
  • the first network node 101 stores at least a part of the first header. This means that the first network node 101 stores at least some of the parameters in the first header. For example, in case of TCP, the first network node 101 may store e.g. the sequence number. In the example of UDP, the first network node 101 may store e.g. the destination port number. Which parameter of the first header that should be stored may be configurable by the operator/vendor.
  • the first network node 101 may store the first header in an internal or external memory.
  • the first network node 101 stores at least part of the first header for the received first data packet to be able to later make a qualified guess about at least a part of a second header comprised in a second data packet, i.e. for the next or a future received data packet.
  • the second network node 105 sends a second data packet to the first network node 101 .
  • the second data packet comprises a second header.
  • the second data packet is sent in response to the first data packet.
  • the second data packet may be for example an acknowledgment of that the first data packet was successfully received in step 201 .
  • the second data packet is not necessarily related to the first data packet.
  • the first and second data packets may be consecutive or non-consecutive data packets.
  • the second data packet may also be formatted according to the protocol, i.e. the same protocol as the first data packet is formatted with.
  • the second data packet may comprise a second payload data in addition to the second header.
  • the second header may be located at any suitable location in the second data packet.
  • the second header may for example be located before second first payload data, the second header may be located after the second payload data, a part of the second header may be located before the second payload data and the remaining part of the second header may be located after the second payload data etc.
  • the second data packet may be received by the second network node 105 from the Internet or internet host before transmission in step 203a to the first network node 101 when the second network node 105 is a base station and the first network node 101 is a wireless device.
  • the second data packet is to be further transmitted to the Internet by the first network node 101 when the second network node 105 is a wireless device and the first network node 101 is a base station.
  • Step 204a
  • the first network node 101 determines side information bits for the second data packet.
  • the side information bits are determined based on that at least part of the second header is assumed to be equal to or associated with the stored at least part of the first header.
  • the side information bits may be for example at least one of an IP address of the second network node 105, a port number of a port of the second network node 105 and a sequence number.
  • the first and second header may be information which is specific to the protocol according to which the first and second data packet is formatted.
  • side information may be associated with a number of hypotheses, and the first network node 101 may determine hypotheses for the bit values of certain header fields where each bit in a hypothesis is assigned a probability.
  • a hypothesis may be derived from the semantics of the communication protocols, i.e., at least part of the second header is equal to or associated with the stored at least part of the first header.
  • the bits associated with a hypothesis may henceforth be called side information bits.
  • the side information bits may be for example at least one of an IP address of the second network node 105, a port number of a port of the second network node 105 and a sequence number.
  • the probabilities may be guided by traffic statistics.
  • the hypotheses may be evaluated in sequential order. E.g.
  • the first network node 101 if a Cyclic Redundancy Check (CRC) check fails for the second data packet, the first network node 101 proceeds to a second hypothesis. As one hypothesis, all stored at least part of the first header should be used. E.g. if a CRC check fails for the second data packet, the first network node 101 proceeds to a second hypothesis. The second hypothesis may be that none of the stored at least part of the first header should be used. Another alternative second hypothesis may be that a subset of the at least part of the first header is used etc. The use of hypothesis will be described in more detail below.
  • CRC Cyclic Redundancy Check
  • the side information bits may be hard information bits, e.g. zeros and ones.
  • the side information bits may be soft information bits, e.g. bit probabilities or log-likelihood ratios.
  • the value of the soft information bits may reflect the certainty of which the at least part of the second header is equal to or associated with the stored at least part of the first header.
  • Step 205a
  • the first network node 101 When the first network node 101 has received the second data packet, it performs decoding of the second data packet.
  • the first network node 101 may also perform channel estimation.
  • the side information bits of the second data packet are used as a priori information in the at least one of channel estimation and decoding of the decoded second data packet.
  • the semantics of the protocol which the first and second data packets are formatted according to may be used in order to boost the channel estimation process, or to boost the decoding process, or to boost both the channel estimation and the decoding process performed by the first network node 101 .
  • the at least part of the first header may be associated with at least part of the second header in different ways.
  • the at least part of the first header may be the same as the at least part of the second header
  • the at least part of the second protocol may be derivable from at least part of the first header
  • the at least part of the second protocol may be calculated from at least part of the first header
  • the at least part of the second protocol and the at least part of the first header may follow a predetermined pattern
  • the at least part of the first header may be correlated with the at least part of the second header etc.
  • the at least part of the first header that was stored in step 202a was the destination address of the first data packet.
  • the at least part of the second header may be the same address, but that the address will be the source address header
  • Step 206a Using an example hypothesis that the source address of the second data packet is the same as the destination address of the first data packet. Each bit of the address field may be assigned a probability that this hypothesis is true.
  • the example hypothesis above is used as input to the decoding processes. The decoding might or might not decode the received second data packet correctly. The CRC check for the packet/code block may indicate if the decoding managed to do the decoding correctly. Step 206a
  • the first network node 101 determines whether or not the decoding of the second data packet was performed correctly by evaluating a CRC for the second data packet.
  • the second data packet is an Internet Protocol version 4 (IPv4) data packet and the second header is part of an IPv4 header.
  • IPv4 Internet Protocol version 4
  • the first network node 101 determines whether it is correct that at least part of the second header is assumed to be equal to or associated with the stored at least part of the first header based on a CRC checksum for the IPv4 header even though it has been determined in step 206a that the decoding of the second data packet was not performed correctly.
  • the first network node 101 may store information indicating that the decoding of the IPv4 header was correctly performed. The stored information indicating the correctness is used in further decoding of the second data packets.
  • Step 208a
  • the first network node 101 may determine IPv4 side information bits for the second data packet based on that the IPv4 header is correct.
  • the first network node 101 may perform a second decoding of the second data packet in which the IPv4 header side information bits for the second data packet are used as a priori information.
  • both arrows 201 b and 203b point to the left, i.e. both the first and second data packet is sent from the second network node 105 to the first network node 101 .
  • arrow 201 a points to the right and arrow 203a points to the left.
  • An example of the scenario in figure 2b is when a session such as e.g. a file transfer sends several consecutive data packets from the same source to the same destination.
  • the embodiment in figure 2b illustrates a method which comprises the following steps, which steps may as well be carried out in another suitable order than described below:
  • the second network node 105 transmits a first data packet to the first network node 101 over the wireless link 1 10.
  • the first data packet is formatted according to a protocol.
  • the protocol may be TCP, IP, UDP, RTP etc.
  • the first data packet comprises a first header. It is the direction of the first data packet that is different between step 201 b in figure 2b and step 201 a in figure 2a.
  • step 201 b in figure 2b it is the second network node 105 that transmits the first data packet
  • step 201 a in figure 2a it is the first network node 101 that transmits the first data packet.
  • the remaining features described in relation to step 201 a is also applicable to step 201 b in figure 2b, but will not be repeated here for the sake of simplicity.
  • the first data packet may be received by the second network node 101 from the Internet or internet host before transmission in step 201 b to the first network node 105 when the second network node 105 is a base station and the first network node 101 is a wireless device.
  • the first data packet is to be further transmitted to the Internet by the first network node 101 when the second network node 105 is a wireless device and the first network node 101 is a base station.
  • the first network node 101 may perform channel estimation and decoding of the first data packet.
  • the first network node 101 may also perform a CRC of the first data packet.
  • step 204b-210b If the CRC performed in step 202b was ok, hypotheses may be determined and side information bits may be stored. If the CRC was not ok, a hypothesis is not determined and side information bits are not stored. In such a case, decoding (and channel estimation) may be performed without side information. Step 204b-210b
  • step 204a-209a in figure 2a correspond to steps 204a-209a in figure 2a and will not be repeated here for the sake of simplicity.
  • FIG. 3 illustrates an example of internet two-way communications over the wireless link 1 10 between the first network node 101 being a NodeB and the second network node 105 being a wireless device.
  • the wireless link 1 10 may be only one hop in the end-to-end communication on Internet 120.
  • the Internet 120 refers to a system of interconnected networks that use the standard IP suite to serve users of the network.
  • Application information sent between Internet hosts 125 is formatted according to protocols such as the TCP and the IP.
  • An Internet host 125 is a network node that participates in a network which uses the IP suite.
  • An Internet host 125 may offer information resources, services and applications to the users or other nodes on the network.
  • An Internet host 125 in addition to other IP hosts, may have at least one IP address assigned to their network interfaces.
  • the application information mentioned above is typically on the application layer of the OSI model. Information generated by an application (such as Internet Explorer) is segmented (i.e. divided into smaller
  • an IP header comprises the IP address of the source host and the IP address of the destination host.
  • a source host may also be referred to as a source network node and the destination host may also be referred to as a destination network node.
  • the application data is first divided into multiple IP data packets. Before the IP data packet is transmitted over the wireless link 1 10 it may be divided into one or more blocks. Each block is channel coded, forming a transport block, and then transmitted.
  • Figure 3 depicts that the source IP address (e.g. 22.222.22.22) of the TCP segment sent in the downlink (the arrow pointing to the left, from the Node B 1 10 to the wireless device 105) becomes the destination IP address (e.g. 22.222.22.22) in the TCP acknowledge data packet sent in the uplink (from the wireless device 105 to the Node B 101 ).
  • the Node B 101 may store header for data packets sent in the downlink and then use this information to make a qualified guess of part of the header transmitted in the uplink data packets. This qualified guess may be used to improve the channel estimation and decoder performance in the uplink.
  • a TCP segment is on the transport layer, and application information id on the application layer of the OSI model.
  • the wireless device 105 when the wireless device 105 transmits a TCP segment in the uplink (the arrow pointing to the right, from the wireless device 105 to the Node B 1 10) comprising a source IP address (e.g. 1 1 1.1 1 1.1 1 .1 1 ) to the Node B 1 10, this IP address becomes the destination address (e.g. 1 1 1.1 1 1.1 1 .1 1 ) in the TCP acknowledge data packet sent in the downlink from the Node B 101 to the wireless device 105.
  • the wireless device 105 may store a header for data packets sent in the uplink to improve the channel estimation and decoding performance in the downlink.
  • Another Internet traffic header pattern that may be exploited is that the header for a data packet received in many cases comprises at least partly the same header as the previous data packet.
  • some header may change in a predictable way for consecutive received data packets. This means that the Node B or the wireless device may store header for a received data packet to make a qualified guess about the part of the header for the next received data packet.
  • FIG. 5 is a signalling diagram illustrating embodiments of a method where the first network node 101 is a base station and the second network node 105 is a wireless device and in a scenario of file upload.
  • the wireless device 105 has 10.0.0.2 as its IP address.
  • a wireless device 105 is uploading a file to a File Transfer Protocol (FTP) server 115 with the IP addressl O.0.0.1.
  • FTP File Transfer Protocol
  • IPv4 data packets are transmitted from the wireless device 105 and received at the base station 101 and then passed on towards the FTP server 1 15.
  • FTP File Transfer Protocol
  • the base station 101 When the first data packet is received at the base station 101 (marked with a box with number 401 within it in figure 4, and corresponding to step 201 b in figure 2b), the base station 101 performs channel estimation and then decoding of the received first data packet. If a CRC of the first data packet is ok, then the destination IP address of the FTP server 1 15 (10.0.0.1 ) and source IP address of the wireless device 105 (10.0.0.2) are stored in the base station 101 (corresponding to step 202b in figure 2b).
  • the base station 101 may create e.g. two different hypotheses.
  • the first hypothesis may be that this second data packet has the same destination and source IP address as the first data packet.
  • the second hypothesis may be that this second data packet does not have the same source and destination IP address as the first data packet.
  • the base station 101 might have a limited amount of processing resources (e.g. the amount is below a threshold) such that only one of the hypotheses may be evaluated. Therefore, the base station 101 only evaluates the first hypotheses by performing at least one of decoding of the data packet and channel estimation assuming that the destination and source IP address is the same as for the first data packet (corresponding to step 205a in figure 2a and step 206b in figure 2b).
  • the base station 101 When the third data packet is received at the base station 101 (marked with a box with number 403 within it in figure 4, and corresponding to step 201 b in figure 2b), the destination IP address of the FTP server 1 15 (10.0.0.1 ) and source IP address of the wireless device 105 (10.0.0.2) are stored in the base station 101 (corresponding to step 202a in figure 2a and step 203b in figure 2b).
  • the base station 101 may create e.g. two new different hypotheses.
  • the hypotheses may be evaluated in any suitable order. One hypothesis may be evaluated at a time, or all hypotheses may be evaluated at the same time. For example, when the first network node 101 has sufficient amount of processing power (i.e. above the threshold), one or more of hypotheses may be evaluated. In another example, the first network node 101 has an amount of processing power which is sufficient for evaluating only one hypothesis.
  • the base station 101 conjectures that statistically the second data packet will, for example, with 90% probability have the same source and destination IP address as the previous data packet (corresponding to step 205a in figure 2 and step 205b in figure 2b).
  • this 90% probability may be associated with the source and destination IP address bits in the setup of the decoding such that the decoder comprised in the base station 101 potentially may decode the source and destination IP address correctly even if the IP addresses of this second data packet is not the same as the first data packet (i.e. the decoder comprised in the base station 101 concludes that the hypothesis is incorrect).
  • Boxes number 405 and 406 in figure 4 illustrates a case when the base station 101 would evaluate an incorrect hypothesis.
  • the first hypothesis may be that the "database check" has the same destination and source IP address as the fourth data packet. As seen in figure 4, this is not correct.
  • the "database check” has a different destination IP address (10.0.0.3) than the fourth data packet (10.0.0.1 ). Thus, the base station 101 evaluates an incorrect hypothesis.
  • Boxes 407 and 408 illustrate fifth, sixth and seven data packets where the base station 101 evaluates a correct hypothesis.
  • the base station 101 may evaluate the hypotheses either in parallel or in sequence in box 402-408. After decoding (i.e. after step 205a in figure 2a and step 206b in figure 2b), it is possible to evaluate the CRC for the code block to see if the whole data packet has been decoded correctly (corresponding to step 206a in figure 2a and step 207b in figure 2b).
  • the data packet may be a code block (i.e. on the link layer in the ISO stack), a TCP segment (i.e. on the transport layer), an IP packet etc.
  • the data packet is an IPv4 data packet it is also possible to check the checksum for the IPv4 header, which includes the destination and source IP address (corresponding to step 206a in figure 2a and step 207b in figure 2b). In other words, even if the CRC for the whole data packet is incorrect, it is possible to check if the hypothesis is correct by checking the IPv4 checksum. If the IPv4 checksum checks ok (corresponding to step 207a in figure 2a and step 208b in figure 2b), the information that the IPv4 header is decoded correctly is stored so that when a Hybrid Automatic Repeat reQuest (HARQ) retransmission is received, this stored information is used in the decoding of the data packet. Note that this is the special case that IPv4 is used and that IPv4 checksum only checks the part of the hypothesis that is part of the IPv4 header.
  • HARQ Hybrid Automatic Repeat reQuest
  • a suitable third hypothesis may be that the source IP address is the same during the time the wireless device 105 is connected to this base station 101.
  • FIG. 5 depicts a sequence diagram of a TCP connection establishment from a wireless device 101 as client and a FTP server 1 15 as server.
  • the wireless device 101 has the example IP address 10.0.0.1 and the FTP server has the example IP address 10.0.0.2.
  • the wireless device 101 stores the TCP and IP header sent in the TCP SYN (TCP sequence number
  • the wireless device 101 makes the hypothesis that the received data packet is the TCP SYN ACK response sent in reply to the TCP SYN set earlier.
  • the wireless device 101 may then use for example the Sequence number information (1 1 1 1 12) as side information during decoding in step 205a in figure 2a and step 206b in figure 2b. Note that the sequence number in the ACK is increased with 1 in this example from 1 1 1 1 1 1 to 1 1 1 1 12.
  • FIG. 6 is a flowchart describing the present method in the first network node 101 for handling data packets in the communications system 100.
  • the first network node 101 comprises a memory having stored on it at least part of a first header associated with a first data packet.
  • the first network node 101 is a base station and the second network node 105 is a wireless device.
  • the first network node 101 is the wireless device and the second network node 105 is the base station.
  • the method comprises the followings steps to be performed by first network node 101 , which steps may be performed in any suitable order other than described below:
  • This step corresponds to step 201 a in figure 2a.
  • the first network node 101 transmits first data packet to the second network node 105.
  • Step 602 This step corresponds to step 201 b in figure 2.
  • the first network node 101 receives the first data packet from the second network node 105.
  • the first network node 101 receives, from a second network node 105, a second data packet comprising a second header.
  • a second data packet comprising a second header.
  • at least part of the second header is associated with the at least part of the first header such that the at least part of the second header is derivable from the at least part of the first header.
  • the first and second data packets may be formatted according to a protocol.
  • the protocol may be at least one of an IP, a TCP, a UDP, and a RTP.
  • the first network node 101 determines side information bits for the second data packet based on that at least part of the second header is assumed to be equal to or associated with the stored at least part of the first header.
  • the side information bits are hard information bits.
  • the side information bits are soft information bits. A value of the soft information bits may reflect a certainty of which of the at least part of the second header is equal to or associated with the stored at least part of the first header.
  • This step corresponds to step 205a in figure 2a and step 206b in figure 2b.
  • the first network node 101 performs at least one of channel estimation and decoding of the second data packet in which the side information bits for the second data packet are used as a priori information.
  • Step 607 corresponds to step 206a in figure 2a and step 207b in figure 2b.
  • the first network node 101 determines whether or not the decoding of the second data packet was performed correctly by evaluating a CRC for the second data packet.
  • the second data packet is an IPv4 data packet and the second header is part of an IPv4 header.
  • the first network node 101 determines whether or not the IPv4 header has been decoded correctly based on a CRC checksum for the IPv4 header even though it has been determined that the decoding of the second data packet was not performed correctly.
  • the first network node 101 determines IPv4 header side information bits for the second data packet based on that the IPv4 header is correct.
  • This step corresponds to step 210b in figure 2.
  • the first network node 101 when IPv4 header side information bits are available, the first network node 101 performs a second decoding of the second data packet in which the IPv4 header side information bits for the second data packet are used as a priori information.
  • Embodiments of the first network node 101 configured to perform the method actions for handling data packets in the communications system 100, as described above in relation to Figures 2a, 2b 3, 4, 5 and 6, is depicted in Figure 7.
  • the first network node 101 is a base station and the second network node 105 is a wireless device. In some embodiments, the first network node 101 is the wireless device and the second network node 105 is the base station.
  • the first network node 101 is adapted to, e.g. by means of a receiving module 701 , receive, from a second network node 105, a second data packet comprising a second header.
  • the first network node 101 may be further adapted to, e.g. by means of the receiving module 701 , receive the first data packet from the second network node 105.
  • the first and second data packets may be formatted according to a protocol, and the protocol may be at least one of IP, TCP, UDP and RTP.
  • the receiving module 701 may also be referred to as a receiving unit, a receiving circuit, receiving means, means for receiving or an input unit.
  • the receiving module 701 may be a receiver or a transceiver.
  • the receiving module 701 may be a wireless receiver of the first network node 101 of a wireless or fixed communications system.
  • the first network node 101 is further adapted to, e.g. by means of a determining module 5 703, determine side information bits for the second data packet based on that at least part of the second header is assumed to be equal to or associated with the stored at least part of the first header.
  • the at least part of the second header may be associated with the at least part of the first header such that the at least part of the second header is derivable from the at least part of the first header.
  • the side information bits may be associated with the at least part of the first header such that the at least part of the second header is derivable from the at least part of the first header.
  • the side information bits are soft
  • a value of the soft information bits may reflect a certainty of which of the at least part of the second header is equal to or associated with the stored at least part of the first header.
  • the first network node 101 may be further adapted to, e.g. by means of the determining module 703, determine whether or not the at least one of channel
  • the second data packet is an IPv4 data packet and the second header is part of an IPv4 header.
  • the first network node 101 may be further adapted to, e.g. by means of the determining module 703, determine whether or not the IPv4 header has been decoded
  • the first network node 101 may be further adapted to, e.g. by means of the determining module 703, determine IPv4 header side information bits for the second data packet based on that the IPv4 header is correct.
  • determining module 703 may also be referred to as a determining unit, a determining circuit, determining means or means for determining.
  • the determining module 703 may be a processor 715 of the first network node 101.
  • the first network node 101 is further adapted to, e.g. by means of a performing module 30 705, perform at least one of channel estimation and decoding of the second data packet in which the side information bits for the second data packet are used as a priori information.
  • the first network node 101 is further adapted to, e.g. by means of the performing module 705, perform a second decoding of the second data packet in which the IPv4 header side 35 information bits for the second data packet are used as a priori information.
  • the performing module 705 may also be referred to as a performing unit, a performing circuit, performing means or means for performing.
  • the performing module 705 may be the processor 715 of the first network node 101 .
  • the first network node 101 is adapted to, e.g. by means of a transmitting module 708, transmit the first data packet to the second network node 105.
  • the receiving module 701 may also be referred to as a transmitting unit, a transmitting circuit, transmitting means, means for transmitting or an output unit.
  • the transmitting module 701 may be a transmitter or a transceiver.
  • the transmitting module 708 may be a wireless transmitter of the first network node 101 of a wireless or fixed communications system.
  • the first network node 101 may further comprise a memory module 710 comprising one or more memory units.
  • the memory 710 has stored on it at least part of a first header associated with the first data packet.
  • the memory module 710 arranged to be used to store data, received data packets, at least part of header, threshold values, time periods, configurations, schedulings, decoding related information, channel estimation information, and applications to perform the methods herein when being executed in the first network node 101.
  • the memory module 710 may also be referred to as a memory, memory circuitry, memory module, memory unit or means adapted to store.
  • the embodiments herein for handling data packets in the communications system 100 may be implemented through one or more processing circuits, such as the processor 715 in the first network node 101 depicted in Figure 7, together with computer program code for performing the functions of the embodiments herein.
  • the processor 715 may be for example a Digital Signal Processor (DSP), Application Specific Integrated Circuit (ASIC) processor, Field-Programmable Gate Array (FPGA) processor or microprocessor.
  • DSP Digital Signal Processor
  • ASIC Application Specific Integrated Circuit
  • FPGA Field-Programmable Gate Array
  • the program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the first network node 101.
  • One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick.
  • the computer program code may furthermore be provided as pure program code on a server and downloaded to the first network node 101 .
  • the processor 715 may also be referred to as a processor, processing circuitry, processing module, processing unit or means adapted to process.
  • a computer program may comprise instructions which, when executed on at least one processor, cause the at least one processor to carry out the method as described in any one of figures 2a, 2b, 3, 4, 5, and 6.
  • a carrier may comprise the computer program.
  • the carrier may be one of an electronic signal, optical signal, radio signal or computer readable storage medium.
  • the receiving module 701 , the determining module 703, the performing module 705 and the transmitting module 708 described above may refer to a combination of analog and digital circuits, and/or one or more processors configured with software and/or firmware, e.g. stored in a memory, that when executed by the one or more processors such as the processor 715 perform as described above.
  • processors as well as the other digital hardware, may be included in a single ASIC, or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).
  • SoC System-on-a-Chip
  • the embodiments herein relates to layer 1 forward error correction boosting based on header such as e.g. TCP/IP header.
  • the embodiments herein apply to a communications system 100 using turbo coding and having internet traffic.
  • the semantics of the protocol such as e.g. the TCP/UDP/IP/RTP communication is used as side information in the first network node 101 , thereby
  • the embodiments herein aims at improving the decoding performance for data traffic such as e.g. TCP/UDP/IP traffic in the uplink of wireless systems such as 3GPP WCDMA and LTE.
  • the embodiments herein exploit side information in the decoding process, thereby lowering the Bit Error Rate.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Conformément à des modes de réalisation, la présente invention concerne un procédé dans un premier nœud de réseau (101) pour traiter des paquets de données dans un système de communication (100). Le premier nœud de réseau (101) comprend une mémoire ayant, mémorisée dans cette dernière, au moins une partie d'un premier en-tête associé à un premier paquet de données. Le premier nœud de réseau (101) reçoit, à partir d'un second nœud de réseau (105), un second paquet de données comprenant un second en-tête. Le premier nœud de réseau (101) détermine des bits d'informations annexes pour le second paquet de données sur la base du fait qu'au moins une partie du second en-tête est supposée être égale ou associée à ladite partie mémorisée du premier en-tête. Le premier nœud de réseau (101) réalise une estimation de canal et/ou un décodage du second paquet de données dans lequel les bits d'informations annexes pour le second paquet de données sont utilisés comme informations a priori.
PCT/EP2014/056825 2014-04-04 2014-04-04 Procédé et nœud pour améliorer les performances de taux d'erreurs sur la base d'informations d'en-tête de paquet WO2015149868A1 (fr)

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Application Number Priority Date Filing Date Title
PCT/EP2014/056825 WO2015149868A1 (fr) 2014-04-04 2014-04-04 Procédé et nœud pour améliorer les performances de taux d'erreurs sur la base d'informations d'en-tête de paquet

Applications Claiming Priority (1)

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PCT/EP2014/056825 WO2015149868A1 (fr) 2014-04-04 2014-04-04 Procédé et nœud pour améliorer les performances de taux d'erreurs sur la base d'informations d'en-tête de paquet

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080240305A1 (en) * 2005-08-16 2008-10-02 Havish Koorapaty Message Decoding With Apriori Information and Soft Combining
US20090177951A1 (en) * 2008-01-07 2009-07-09 Qualcomm Incorporated Priori decoding scheme based on map messages
US8489968B2 (en) * 2008-05-06 2013-07-16 Alcatel Lucent Recovery of transmission errors

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080240305A1 (en) * 2005-08-16 2008-10-02 Havish Koorapaty Message Decoding With Apriori Information and Soft Combining
US20090177951A1 (en) * 2008-01-07 2009-07-09 Qualcomm Incorporated Priori decoding scheme based on map messages
US8489968B2 (en) * 2008-05-06 2013-07-16 Alcatel Lucent Recovery of transmission errors

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