# Patent

## Title
Random linear network encoded data transmission from user equipment

## Abstract

For random linear network encoded data transmission from user equipment, a method receives a Galois field and a resource allocation for transmission of data from the user equipment. The method further encodes a first set of k data packets from a first data ensemble into a first random linear network coded (RLNC) packet as a function of the Galois field. The first RLNC packet includes an ensemble number that identifies the first data ensemble, an encoding vector, and a sequence of RLNC sub-packets. In addition, the method generates a first protocol data unit (PDU) that comprises a number of RLNC sub-packets of the first RLNC packet. A size of the first PDU does not exceed the resource allocation.

## Background
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Patent Application No. 62/245,740, entitled “Random Linear Network Encoded Data Transmission From User Equipment” and filed on Oct. 23, 2015 for Murali Narasimha, et al., which is incorporated herein by reference.


FIELD
The subject matter disclosed herein relates to random linear network encoded data and more particularly relates to transmitting random linear network encoded data from user equipment
BACKGROUND
Description of the Related Art
User equipment such as mobile telephones typically communicates with a single base station.
BRIEF SUMMARY
A method for random linear network encoded data transmission from user equipment is disclosed. The method receives a Galois field and a resource allocation for transmission of data from user equipment. The method further encodes a first set of k data packets from a first data ensemble into a first random linear network coded (RLNC) packet as a function of the Galois field. The first RLNC packet includes an ensemble number that identifies the first data ensemble, an encoding vector, and a sequence of RLNC sub-packets. In addition, the method generates a first protocol data unit (PDU) that comprises a number of RLNC sub-packets of the first RLNC packet. A size of the first PDU does not exceed the resource allocation. The method further transmits the PDU. An apparatus also performs the functions of the method.



BRIEF DESCRIPTION OF THE DRAWINGS
A more particular description of the embodiments briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only some embodiments and are not therefore to be considered to be limiting of scope, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:
FIG. 1 is a schematic block diagram illustrating one embodiment of a data transmission system;
FIG. 2A is a schematic block diagram illustrating one embodiment of encoding data;
FIG. 2B is a schematic block diagram illustrating one embodiment of an RLNC packet;
FIG. 2C is a schematic block diagram illustrating one embodiment of a pre-selection map;
FIG. 3A is a schematic block diagram illustrating one embodiment of an RLNC encoding process;
FIG. 3B is a schematic block diagram illustrating one embodiment of data packets with sub-packets;
FIG. 3C is a schematic block diagram illustrating one embodiment of resized data packets;
FIG. 3D is a schematic block diagram illustrating one embodiment of an allocation process;
FIG. 3E is a schematic block diagram illustrating one alternate embodiment of an allocation process;
FIG. 3F is a drawing illustrating determining which data can be acknowledged as having been decoded;
FIG. 3G is a drawing illustrating one embodiment of augmenting a transfer matrix;
FIG. 3H is a schematic block diagram illustrating one embodiment of inter-user equipment data transmission;
FIG. 3I is a schematic block diagram illustrating one embodiment of inter-user equipment data and pre-selection map exchange;
FIG. 4 is a schematic block diagram illustrating one embodiment of a computer;
FIG. 5A is a schematic flow chart diagram illustrating one embodiment of an RLNC packet transmission method;
FIG. 5B is a schematic flow chart diagram illustrating one embodiment of a reception point encoding method; and
FIG. 5C is a schematic flowchart diagram illustrating one embodiment of an RLNC packet decoding method.



DETAILED DESCRIPTION
As will be appreciated by one skilled in the art, aspects of the embodiments may be embodied as a system, method or program product. Accordingly, embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, embodiments may take the form of a program product embodied in one or more computer readable storage devices storing machine readable code, computer readable code, and/or program code, referred hereafter as code. The storage devices may be tangible, non-transitory, and/or non-transmission. The storage devices may not embody signals. In a certain embodiment, the storage devices only employ signals for accessing code.
Many of the functional units described in this specification have been labeled as modules, in order to more particularly emphasize their implementation independence. For example, a module may be implemented as a hardware circuit comprising custom VLSI circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.
Modules may also be implemented in code and/or software for execution by various types of processors. An identified module of code may, for instance, comprise one or more physical or logical blocks of executable code which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together, but may comprise disparate instructions stored in different locations which, when joined logically together, comprise the module and achieve the stated purpose for the module.
Indeed, a module of code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within modules, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different computer readable storage devices. Where a module or portions of a module are implemented in software, the software portions are stored on one or more computer readable storage devices.
Any combination of one or more computer readable medium may be utilized. The computer readable medium may be a computer readable storage medium. The computer readable storage medium may be a storage device storing the code. The storage device may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.
More specific examples (a non-exhaustive list) of the storage device would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
Code for carrying out operations for embodiments may be written in any combination of one or more programming languages including an object oriented programming language such as Python, Ruby, Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the “C” programming language, or the like, and/or machine languages such as assembly languages. The code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).
Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to,” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise.
Furthermore, the described features, structures, or characteristics of the embodiments may be combined in any suitable manner. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of an embodiment.
Aspects of the embodiments are described below with reference to schematic flowchart diagrams and/or schematic block diagrams of methods, apparatuses, systems, and program products according to embodiments. It will be understood that each block of the schematic flowchart diagrams and/or schematic block diagrams, and combinations of blocks in the schematic flowchart diagrams and/or schematic block diagrams, can be implemented by code. These code may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the schematic flowchart diagrams and/or schematic block diagrams block or blocks.
The code may also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function/act specified in the schematic flowchart diagrams and/or schematic block diagrams block or blocks.
The code may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the code which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
The schematic flowchart diagrams and/or schematic block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of apparatuses, systems, methods and program products according to various embodiments. In this regard, each block in the schematic flowchart diagrams and/or schematic block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions of the code for implementing the specified logical function(s).
It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, of the illustrated Figures.
Although various arrow types and line types may be employed in the flowchart and/or block diagrams, they are understood not to limit the scope of the corresponding embodiments. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the depicted embodiment. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted embodiment. It will also be noted that each block of the block diagrams and/or flowchart diagrams, and combinations of blocks in the block diagrams and/or flowchart diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and code.
The description of elements in each figure may refer to elements of proceeding figures. Like numbers refer to like elements in all figures, including alternate embodiments of like elements.
FIG. 1 is a schematic block diagram illustrating one embodiment of a data transmission system 100. The system 100 may include a network coding node 105, one or more reception points 110, and user equipment 115. In the depicted embodiment, a first reception point 110a and a second reception point 110b are shown, but “reception points 110” may refer to any number of reception points 110.
The network coding node 105 may include one or more servers. In a certain embodiment, the network coding node 105 includes a transmitter and/or receiver. The network coding node 105 may communicate with the reception points 110 over a backhaul channel 120. The reception points 110 may be evolved node B (eNB) Long Term Evolution (LTE) base stations or access points of a millimeter-wave based Communication System.
The user equipment 115 may generate protocol data units (PDU) from data packets and communicate the PDU to the reception points 110 over one or more wireless frequencies 125. The user equipment 115 may be a mobile telephone, a tablet computer, a laptop computer, an embedded computing device, or the like. In one embodiment, user equipment 115 may communicate with other user equipment 115 through a device-to-device channel 130. In one embodiment, the device-to-device channel 130 includes the wireless frequencies 125. Alternatively, the device-to-device channel 130 may include a wireless network such as a Wi-Fi network, a BLUETOOTH® network, or the like.
In the past, the user equipment 115 typically communicated with a single reception point 110. However, it may be advantageous for the user equipment 115 to concurrently communicate with multiple reception points 110. For example, higher wireless frequencies 125 support higher data transmission rates. However, higher frequencies and higher data transmission rates often reduce the effective range of communication over the wireless frequencies 125. The use of multiple reception points 110 may increase the reliability and efficiency of communications between the reception points 110 and the user equipment 115.
Unfortunately, if one reception point 110 loses a PDU, the PDU must be retransmitted, reducing overall data transmission performance. In addition, if the PDU is delayed, the overall data transmission performance is also reduced.
The embodiments described herein encode data packets as RLNC packets that distribute the data that is communicated from the user equipment 115 to the plurality of reception points 110 as will be described hereafter. As a result, data transmission performance is maintained even when PDU are lost and/or delayed.
FIG. 2A is a schematic block diagram illustrating one embodiment of encoding data 200. The encoding data 200 maybe organized as a data structure in a memory. In the depicted embodiment, the encoding data 200 includes a Galois field 205, encoding vectors 210, a resource allocation 280, data traffic characteristics 285, one or more data packets 215, one or more resized data packets 230, one or more RLNC packets 220, and one or more PDU 255.
The Galois field 205 may store a finite number of numeric values. In one embodiment, the Galois field 205 is generated based on a predetermined size of the Galois field. The resource allocation 280 may indicate an allocation for the transmission of data from the user equipment 115. Alternatively, the resource allocation 280 may indicate available storage on the reception points 110. The data traffic characteristics 285 may include packet arrival requirements specifying how frequently a PDU may be received by the reception points 110. In addition, the data traffic characteristics 285 may include delay requirements specifying a delay between PDU received by the reception points 110.
Each data packet 215 may comprise data that is to be communicated from the user equipment 115 through the reception points 110 to the network coding node. In one embodiment, each data packet 215 is a member of a packet ensemble. Each packet ensemble may include a plurality of data packets 215.
The resized data packets 230 are data packets 215 that have been resized. In one embodiment, the resized data packets 230 each have a specified packet length. The resizing of the data packets 215 into resized data packets 230 is described hereafter in FIGS. 3B-C.
The RLNC packets 220 may be generated from the resized data packets 230. In addition, the PDU 255 may each be generated from one or more RLNC packets 220 as will be described hereafter.
FIG. 2B is a schematic block diagram illustrating one embodiment of an RLNC packet 220. The RLNC packet 220 may be organized as a data structure in a memory. In the depicted embodiment, the RLNC packet 220 includes an ensemble number 260, an inactivity timer 265, an encoding vector 210, and one or more RLNC sub-packets 365. The RLNC packet 220 may also include additional elements. The ensemble number 260 and inactivity timer 265 may be included in a header of the RLNC packet 220. In another embodiment, the inactivity timer 265 may be included in a separate data structure instead of in the RLNC packet 220.
The ensemble number 260 identifies a packet ensemble of data packets 215 that are used to generate the RLNC packet 220. In one embodiment, each data packet 215 of a first packet ensemble shares the same ensemble number 260.
The inactivity timer 265 may specify a time interval for which the reception points 110 will continue to receive the RLNC packets 220. In one embodiment, the inactivity timer 265 is reduced in response to decode feedback that the network coding node 105 decoded a packet ensemble. Alternatively, the current inactivity timer 265 may be smaller than initial inactivity timer value in response to decode feedback that the network coding node 105 decoded the packet ensemble. In one embodiment the inactivity timer 265 may be communicated to a reception point 110 with the RLNC packet 220. In another embodiment, the inactivity timer 265 may be configured independently using other signaling mechanisms between the user equipment 115 and the network coding node 105.
The encoding vector 210 may be randomly selected from the Galois field 205. Each RLNC packet 365 may comprise data from data packets 215 encoded as a function of the encoding vector 210 as will be described hereafter.
FIG. 2C is a schematic block diagram illustrating one embodiment of a pre-selection map 245. The pre-selection map 245 may be organized as a data structure in a memory. An instance of the pre-selection map 245 may reside on each of a plurality of user equipment instances 110. An instance of the pre-selection map 245 may be communicated between user equipment instances 110. The pre-selection map 245 may store a plurality of user equipment indices 295 that correspond to data packets 215, with each user equipment index 295 indicating the source user equipment instance 110 that contributed the data packet 215 to a corresponding position in an RLNC packet 220. For example, the first user equipment index 295a may record an identifier for user equipment 115 that contributes a first data packet 215 and/or a first sub-packet 305 to a first position within an RLNC packet 220. Similarly, the second user equipment index 295b may record an identifier for user equipment 115 that contributes a second data packet 215 and/or a second sub-packet 305 to a second position within the RLNC packet 220.
The pre-selection map 245 may include any number of user equipment indices 295. For example, the pre-selection map 245 may include user equipment indices 295 for seven data packets 215, with the user equipment indices 295 storing values for one of five instances of user equipment 115. The RLNC packet 220 may be formed from data packets 215 and/or sub-packets 305 from a plurality of user equipment 115. An example of using the pre-selection map 245 is shown in FIG. 3I.
FIG. 3A is a schematic block diagram illustrating one embodiment of a RLNC encoding process 203. The process 203 may encode the data packets 215 as RLNC packets 220 and allocate the RLNC packets 220 to one or more PDU 255. In the depicted embodiment, a packet ensemble 240 comprises data packets 215 of varying packet lengths. The packet resizing process 225 resizes the data packets 215 of the packet ensemble 240 as resized data packets 230. Each resized data packet 230 is a specified packet length.
A network coding process 235 encodes the resized data packets 230 as RLNC packets 220. In an alternative embodiment, the network coding process 235 encodes the data packets 215 as the RLNC packets 220.
An allocation process 265 generates PDU 255 from the one or more RLNC packets 220. A transmission process 250 may transmit the PDU 255 from the user equipment 115 to the reception points 110.
FIG. 3B is a schematic block diagram illustrating one embodiment of data packets with sub-packets 305. A plurality of data packets 215 is shown. Each data packet 215 includes one or more sub-packets 305. In addition, the data packets 215 may be of different packet lengths. In the depicted embodiment, the data packets 215 are of different packet lengths because the data packets 215 comprise different numbers of sub-packets 305. Alternatively, the data packets 215 may include the same number of sub-packets 305. The data packets 215 may be included in a packet ensemble 240.
The packet resizing process 225 may resize the data packets 215 so that each data packet 215 has a specified packet length l 315. In one embodiment, the specified packet length l 315 is greater than or equal to a total number of sub-packets 305 in the plurality of data packets 215 divided by a value k. The determination of k is described hereafter.
FIG. 3C is a schematic block diagram illustrating one embodiment of resized data packets 230. In the depicted embodiment, the packet resizing process 225 resizes the data packets 215 of FIG. 3B to the specified packet length l 315. In one embodiment, sub-packets 305 from long data packets 215 with greater than l 315 sub-packets 305 are distributed to short data packets 215 with less than l 315 sub-packets 305. In a certain embodiment, one or more null sub-packets 310 may be appended to short data packets 215 with less than l 315 sub-packets 305.
In one embodiment, one or more sub-packets 305 may be encoded to form an RLNC sub-packet 365. In the depicted embodiment, an RLNC sub-packet 365 may be generated by encoding a row 370 of sub-packets 305.
FIG. 3D is a schematic block diagram illustrating one embodiment of the allocation process 265. In the depicted embodiment, a plurality of packet ensembles 240 is allocated to a plurality of PDU 255. In one embodiment, each PDU 255 is filled with one RLNC packet 220 from each packet ensemble 240 of a plurality of packet ensembles 240. Alternatively, each PDU 255 is filled with one RLNC sub-packet 365 from each packet ensemble 240 of the plurality of packet ensemble 240.
FIG. 3E is a schematic block diagram illustrating one alternate embodiment of the allocation process 265. In the depicted embodiment, a PDU 255 is initially filled with RLNC sub-packets 365 from the first RLNC packet 220a and subsequently filled with RLNC sub-packets 365 from the second RLNC packet 220b. 
FIG. 3F is a drawing illustrating determining which data can be acknowledged as being decodable. The depicted embodiment corresponds to a k of 4, with PDU 255 constructed for 4 RLNC packets 220 generated from one packet ensemble 240 of data packets 215. Each RLNC packet 220 comprises RLNC sub-packets 365. sji refers to the j-th sub-packet 305 of the i-th data packet 215. RLNC sub-packets 365 are generated by encoding rows of sub-packets 305. For example, encoding of sub-packets 305 s11, s12, s13, s14 yields an RLNC sub-packet 365. Similarly, encoding of sub-packets 305 s31, s32, s33, s34 yields another RLNC sub-packet 365. In the depicted embodiment, a first PDU 255a comprises RLNC sub-packets 365 r11, r22, r33, r44, wherein each rj1 is obtained by encoding the j-th row. The second PDU 255b comprises RLNC sub-packets 365 r12, r22, r32, r42, r52, wherein each rj2 is obtained by encoding the j-th row. The third PDU 255c comprises RLNC sub-packets 365 r13, r23, r33, r43, r53, r63, wherein rj3 is obtained by encoding the j-th row. The fourth PDU 255d comprises RLNC sub-packets 365 r14, r24, r34, r44, r54, r64, r74, wherein rj4 is obtained by encoding the j-th row.
Upon receiving the fourth PDU 255d, the network coding node 105 may determine that the network coding node 105 has received adequate RLNC sub-packets 365 to enable decoding of sub-packets 305 s11 . . . s44, s12 . . . s42, s13 . . . s43 and s14 . . . s44. The network coding node 105 can further determine that network coding node 105 has not received adequate RLNC sub-packets 365 to enable decoding of certain sub-packets 305, for example, s51, s52, s53 and s54. The network coding node 105 may send an acknowledgement indicating that s11 . . . s44, s12 . . . s42, s13 . . . s43 and s14 . . . s44 can be decoded. In particular, s11, s12, s13, s14 can be decoded because four linear combinations of s11, s12, s13, s14 have been received; s21, s22, s23, s24 can be decoded because four linear combinations of s21, s22, s23, s24 have been received; s31, s32, s33, s34 can be decoded because four linear combinations of s31, s32, s33, s34 have been received; and s41, s42, s43, s44 can be decoded because four linear combinations of s41, s42, s43, s44 have been received. In subsequent PDUs 255, the user equipment 115 need not send RLNC sub-packets 365 generated from the first four rows 325 in response to receiving the acknowledgement.
In one embodiment, when a PDU 255 is received by the network coding node 105, the RLNC sub-packets 365 of the PDU 255 may be considered decoded by the user equipment 115. The network coding node 105 and/or reception points 110 may communicate the receipt of the PDU 255 to the user equipment 115 using decode feedback. The network coding node 105 and/or reception points 110 may communicate the decode feedback before the network coding node 105 has decoded the RLNC sub-packets 365. For example, if decode feedback is communicated from the network coding node 105 and/or reception points 110 indicating that the second PDU 255b, the third PDU 255c and the fourth PDU 255d were received, the RLNC sub-packets 365 within area 325 may be considered decoded by the user equipment 115.
FIG. 3G is a drawing illustrating one embodiment of augmenting a transfer matrix 330. An initial transfer matrix 330 may include coefficients c for encoding vectors 210. A test matrix 335 may be constructed from the initial transfer matrix 330 with an encoding vector 210 added to the transfer matrix 330. The incremental encoding vector 210 may augment the transfer matrix 330 if the test matrix 335 has a higher rank than the transfer matrix, such as is depicted. The encoding vector 210 may augment the transfer matrix 330 if the encoding vector 210 is linearly independent of the rows of the transfer matrix 330.
FIG. 3H is a schematic block diagram illustrating one embodiment of inter-user equipment data transmission. In the depicted embodiment, the first user equipment 115a communicates a first data packet 215a to the second user equipment 115b using the device-to-device channel 130. The second user equipment 115b may encode the first data packet 215a in a second RLNC packet 220b so that the second RLNC packet 220b is derived from at least the first data packet 215a. In one embodiment, the second RLNC packet 220b is derived from the first data packet 215a and from other data packets 215 present on the second user equipment 115b. 
The first data packet 215a may be positioned within the second RLNC packet 220b based on a pre-selection map. In one embodiment, the pre-selection map indicates the location within the second RLNC packet 220b of RLNC sub-packets 365 from other user equipment 115. The second user equipment 115b may further generate a second PDU 255b that includes the second RLNC packet 220b and communicate the second PDU 255b to one or more reception points 110 over the wireless frequencies 125.
FIG. 3I is a schematic block diagram illustrating one embodiment of inter-user equipment data and pre-selection map 245 exchange. In the depicted embodiment, pre-selection maps 245 and data packets 215 are shown residing on three instances of user equipment 115a, 115b, and 115c at consecutive times. For simplicity, only three instances of user equipment 115 and three user equipment indices 295 are illustrated, but the embodiments may be practiced with any number of instances of both user equipment 115 and user equipment indices 295.
At an initial time T0, each instance of user equipment 115 includes a pre-selection map 245 in which each user equipment index 295 is set to zero. At time T1, the first user equipment 115a generates a first data packet 215a. The first user equipment 115a may update the pre-selection map 245 so that the first user equipment index 295a includes the index for the first user equipment 115a, in this example “1.”
During time T2, the first user equipment 115a communicates the first data packet 215a and the pre-selection map 245 to the second and third user equipment 115b-c. Any of the first, second or third user equipment 115a-c may encode the first data packet 215a into an RLNC packet 220 and communicate the RLNC packet 220 to a reception point 110. For example, the third user equipment 115c may encode the first data packet 215a p1 as [c11 0 0]×[p1 0 0]T, wherein c11 is a coefficient from an encoding vector 210.
During time T3, the third user equipment 115c generates a second data packet 215b. The third user equipment 115c may update the pre-selection map 245 so that the second user equipment index 295b includes the index for the third user equipment 115c, in this example “3.”
During time T4, the third user equipment 115c communicates the second data packet 215b and the pre-selection map 245 to the first and second user equipment 115a-b. Any of the first, second, or third user equipment 115a-c may encode the first data packet 215a and the second data packet 215b into an RLNC packet 220 and communicate the RLNC packet 220 to the reception point 110. For example, the first user equipment 115a may encode the first data packet p1 215a and the second data packet p2 215b as [c12 c22 0]×[p1 p2 0]T, wherein c11 and c22 are coefficients from the encoding vector 210.
During time T5, the second user equipment 115b generates a third data packet 215c. The second user equipment 115b may update the pre-selection map 245 so that the third user equipment index 295c includes the index for the second user equipment 115b, in this example “2.”
During time T6, the second user equipment 115b communicates the third data packet 215c and the pre-selection map 245 to the first and third user equipment 115a,c. Any of the first, second, or third user equipment 115a-c may encode the first data packet 215a, the second data packet 215b and the third data packet 215c into an RLNC packet 220 and communicate the RLNC packet 220 to the reception point 110. For example, the second user equipment 115b may encode the first data packet p1 215a, the second data packet p2 215b and the third data packet p3 215c as [c13 c23 c33]×[p1 p2 p3]T, wherein c13, c23 and c33 are coefficients from the encoding vector 210.
FIG. 4 is a schematic block diagram illustrating one embodiment of a computer 400. The computer 400 may be embodied in one or more of the network coding node 105, the reception points 110, and/or the user equipment 115. In the depicted embodiment, the computer 400 includes a processor 405, a memory 410, and communication hardware 415. The memory 410 may include a semiconductor storage device, a hard disk drive, an optical storage device, a micromechanical storage device, or combinations thereof. The memory 410 may store code. The processor 405 may execute the code. The communication hardware 415 may communicate with other devices.
FIG. 5A is a schematic flow chart diagram illustrating one embodiment of an RLNC packet transmission method 500. The method 500 may generate an RNLC packet 220 as part of a PDU 255 at the user equipment 115 and transmit the PDU 255 through the reception points 110 to the network coding node 105. The method 500 may be performed by the processor 405 of the user equipment 115.
The method 500 starts, and in one embodiment, the processor 405 receives 505 the Galois field 205 from the network coding node 105 through the reception points 110. In addition, the processor 405 may receive a resource allocation 280 and/or data traffic characteristics 285 from the network coding node 105.
In one embodiment, the processor 405 selects 515 a packet ensemble 240 of data packets 215. The data packets 215 are to be communicated to the network coding node 105 and may include audio, video, and/or data.
The processor may resize 520 the data packets 215 of the packet ensemble 240 by calculating the specified packet length l 315, distributing sub-packets 305 from long data packets 215 with greater than l sub-packets 305 to short data packets 215 with less than l sub-packets 305, and appending null sub-packets 310 to short data packets 215 with less than l sub-packets 305 as illustrated in FIG. 3C. In one embodiment, the resized data packet 230 and/or the data packets 215 are communicated from the first user equipment 115a to the second user equipment 115b. 
The processor 405 may generate 525 the encoding vector 210. In a certain embodiment, the processor 405 generates the encoding vector 210 as comprising k encoding coefficients [c1i, c2i, . . . cki] by randomly selecting elements from the Galois field 205. Each coefficient c is a member of the Galois field 205.
In one embodiment, the processor 405 encodes 530 a first set of k resized data packets 230 from a first data ensemble 240a into r RLNC packets 220 as a function of the Galois field 205. The value k may be an integer and may be calculated as a function of a resource allocation 280 and data traffic characteristics 285. The value k may be selected such that the RLNC packets 220 and/or PDU 255 do not exceed a resource allocation 280 for the network coding node 105 and/or the reception points 110. In a certain embodiment, r≧k. For example, at least one data packet 215 may be encoded with two or more encoding vectors 210 into two or more RLNC packets 220 and the two or more RLNC packets 220 communicated to the network encoding node 105. As a result, some RLNC packets 220 may be redundant. In addition, some RLNC packets 220 may include redundant RLNC sub-packets 365.
The processor 405 may encode 530 the first set of k data packets p1, . . . , pk 215 as the plurality of r RLNC packets 220. Each RLNC packet R 220 may be calculated as shown in Equation 1, where i is an index number, pi is a data packet 215, and [c1, c2, . . . , ck] is the encoding vector.

R=Σi=1kcipi  Equation 1

The data packets p1, . . . , pk 215 may each have l sub-packets. Consequently, Equation 1 yields an RLNC packet R 220 which has l RLNC sub-packets r1, r2, . . . , rl 365. More specifically, the j-th RLNC sub-packet rj 365 can be obtained as shown in the following equation, where i is an index number, [c1, c2, . . . , ck] is the encoding vector 210, and s1j, s2j, . . . , skj are the j-th sub-packets 305 of p1, . . . , Pk respectively as shown in Equation 2.

rj=Σi=1kcisij  Equation 2

The processor 405 may generate 535 a plurality of PDU 255 from a plurality of RLNC packets 220. The RLNC sub-packets 365 of the RLNC packets 220 may be allocated to the PDU 255 at a physical layer of a communication stack. Each PDU 255 may be filled with one RLNC packet 220 from each data ensemble 240 of a plurality data ensemble 240 and/or one RLNC sub-packet 365 from each data ensemble of a plurality data ensemble 240 as illustrated in FIG. 3D. Alternatively, each PDU 255 is initially filled with RLNC sub-packets 365 from the first RLNC packet 220a and subsequently filled with RLNC sub-packets 365 from the second RLNC packet 220b as illustrated in FIG. 3E. In one embodiment, the number of RLNC sub-packets 365 of each RLNC packet 220 is such that the size of the first PDU 255 does not exceed the resource allocation 280.
In one embodiment, the processor 405 encodes 530 a second set of k data packets 215b from a second data ensemble 240b into a second RLNC packet 220b. The second RLNC packet 220b comprises a sequence of RLNC sub-packets 365. The processor 405 may include in the first PDU 255a a maximum number of RLNC sub-packets 365 of the second RLNC packet 220b such that the size of the PDU 255 does not exceed the resource allocation 280.
The processor 405 may encode 530 the first set of k data packets from the first data ensemble into a second RLNC packet 220b. The second RLNC packet 220b may comprise a sequence of RLNC sub-packets 365. The processor 405 may further include in the first PDU 255a, a maximum number of RLNC sub-packets 365 of the second RLNC packet 220b that can be included without the PDU 255 exceeding the size of the resource allocation 280.
In one embodiment, the processor 405 transmits 540 the PDU 255 with the RLNC packet 220. The PDU 255 and/or RLNC packet 220 may be transmitted 540 by the user equipment 115 to one or more reception points 110. The processor 405 may iteratively transmit 540 the RLNC packets 220 and/or PDU 255.
The processor 405 may transmit 540 the PDU 255 and/or RLNC packets 220 until decode feedback indicates that a packet ensemble 240 is decoded from the transmitted RLNC packets 220. In one embodiment, the processor 405 receives 545 the decode feedback from the network coding node 105 and/or reception points 110. The decode feedback may be selected from the group consisting of an indication that a packet ensemble 240 can be decoded (referred to as an RLNC ACK), an acknowledgement of a receipt of an RLNC packet 220 that may be referred to as a packet ACK, an indication of additional RLNC packets 220 required to decode the packet ensemble 240, an indication of a number of RLNC packets 240 received, a negative acknowledgement of not receiving the one of the RLNC packets 220 that may be referred to as a packet NACK, and a negative acknowledgement indicating that the network coding node 105 and/or reception points 110 do not have sufficient RLNC packets 220 to decode the packet ensemble 240. The packet ACK and the packet NACK may be signaling at the physical layer. For example, the packet ACK may be a Hybrid ARQ acknowledgement and the packet NACK may be a Hybrid ARQ negative acknowledgement. The decode feedback may include the ensemble number 260.
The decode feedback may indicate a maximum data reception rate for network coding node 105 and/or reception points 110. In one embodiment, the decode feedback includes a retransmission request indicating that the first RLNC packet 220 is not received. The retransmission request may be referred to as HARQ-NACK. The first RLNC packet 220 may be retransmitted 540 in response to the retransmission request.
In one embodiment, the PDU 255 is transmitted 540 from first user equipment 115a with increased power in response to communication over the device-to-device channel 130 from second user equipment 115b that the second user equipment 115b is communicating with a first reception point 110 that is not in communication with the first user equipment 115a. As a result, the first user equipment 115a is more likely to communicate with the first reception point 110.
The processor 405 may determine 547 if the transmitted packet ensemble 240 is decoded. The packet ensemble 240 may be decoded if the decode feedback from the network coding node 105 and/or reception points 110 includes an indication that all sub-packets 305 of the packet ensemble 240 have been received by the network coding node 105 and/or reception points 110. Alternatively, the packet ensemble 240 may be considered decoded if the decode feedback from the network coding node 105 and/or reception points 110 includes an indication that the packet ensemble 240 can be decoded.
If the transmitted packet ensemble 240 is not considered decoded the processor 405 may iteratively generate 525 another encoding vector 210 and encode 530 another RLNC packet 220 for the packet ensemble 240, generate 535 another PDU 255 from the encoded RLNC packet 220, and transmit 540 the PDU 255. If the processor 405 determines 545 that the packet ensemble 240 is decoded, the processor 405 may select 515 a next packet ensemble 240.
FIG. 5B is a schematic flow chart diagram illustrating one embodiment of a reception point encoding method 550. The method 550 may encode RLNC packets 220 at a reception point 110. The method 550 may be performed by the processor 405 of the reception point 110.
The method 550 starts, and in one embodiment, the processor 405 configures 555 a first reception point 110 to receive first data packets 215 from a first set of user equipment 115. The first reception point 110 may encode RLNC packets 220 for the first set of user equipment 115.
The processor 405 may indicate 560 an assignment of unique indices to each of the first set of user equipment 115. The unique indices may identify each of the first set of user equipment 115.
The processor 405 may receive 565 data packets 215 associated with unique indices and the first set of user equipment 115. The data packets 215 may be received from the first set of user equipment 115. In one embodiment, the data packets 215 may be encoded in an RLNC packet 220 and/or PDU 255. The data packets 215 may be extracted from the RLNC packet 220 and/or the PDU 255.
In one embodiment, the processor 405 encodes 570 the data packets 215 into an RLNC packet 220. The data packets 215 may be encoded 570 with coefficients as illustrated in Equations 1 and 2. The coefficients may be randomly selected from the Galois field 205. In one embodiment, coefficients of encoding vectors 210 that have not been received from the user equipment 115 may be set to zero. The processor 405 may further communicate 575 the RLNC packet 220 to the network coding node 105.
The processor 405 may determine 580 if the network coding node 105 has decoded and/or can decode the data packets 215 from the RLNC packet 220. If the data packets 215 hasn't been or cannot be decoded, the processor 405 may encode 570 and communicate 575 another RLNC packet 220. If the data packets 215 have been and/or can be decoded, the processor 405 may receive 565 additional data packets 215.
FIG. 5C is a schematic flowchart diagram illustrating one embodiment of an RLNC packet decoding method 600. The method 600 may decode the RLNC packet 220 and/or PDU 255 at the network coding node 105 and/or reception points 110. The method 600 may be performed by the processor 405 of the network coding node 105 and/or reception points 110.
The method 600 starts, and in one embodiment, the processor 405 generates 605 the Galois field 205. The Galois field 205 may be retrieved from a file.
The processor 405 may receive 610 the RLNC packet 220 and/or PDU 255 from the user equipment 115. In one embodiment, the processor 405 receives 610 a first RLNC packet 220a from the first reception point 110a. The first RLNC packet 220a may be encoded from a first plurality of data packets 215. The processor 405 may further receive 610 a second RLNC packet 220b from the second reception point 110b. The second RLNC packet 220b may be encoded from a second plurality of data packets 215.
The processor 405 may determine 615 the encoding vector 210 from the RLNC packet 220 and/or RLNC packets 220, referred to hereafter in the singular. The encoding vector 210 may be extracted from the RLNC packet 220. If a transfer matrix 330 has not been created, the processor 405 creates a transfer matrix 330 consisting of a single row. The single row may be set to the extracted encoding vector 210.
In one embodiment, the processor 405 communicates 620 decode feedback to the user equipment 115. The decode feedback may include the ensemble number 260. In a certain embodiment, the decode feedback includes an acknowledgment of receipt of the RLNC packet 220 and/or PDU 255.
The processor 405 may determine 625 if one or more extracted incremental encoding vectors 210 augments the transfer matrix 330. The incremental encoding vectors 210 may augment the transfer matrix 330 if the test matrix 335 comprising the transfer matrix 330 with the incremental encoding vector 210 added to the transfer matrix 330 as an additional row of the transfer matrix 330 has a higher rank than the transfer matrix 330.
If the incremental encoding vector 210 does not augment the transfer matrix 330, the processor 405 may discard 635 the incremental encoding vector 210. In addition, the processor 405 may communicate 650 decode feedback with an indication that additional RLNC packets 220 are required to decode the packet ensemble 240, a negative acknowledgment indicating that the user equipment 115 does not have sufficient RLNC packets 220 to decode the packet ensemble 240, or combinations thereof. The processor 405 may further receive 610 a next RLNC packet 220 and/or PDU 255.
If the incremental encoding vector 210 does augment the transfer matrix 330, the processor 405 may extend 630 the transfer matrix 330 with the incremental encoding vector 210 by adding the incremental encoding vector 210 as a row of the transfer matrix 330. The processor 405 may further determine 640 if the packet ensemble 240 can be decoded. For example, the processor 405 may determine 640 that the packet ensemble 240 can be decoded if the n original data packets 215 can be decoded from the k RNLC packets 220.
If the packet ensemble 240 cannot be decoded, the processor 405 may continue to receive 610 RLNC packets 220 and/or PDU 255 and communicate 620 decode feedback with an indication of additional RLNC packets 220 required to decode the packet ensemble 240 from the n original data packets, an indication of the number of RLNC packets 220 received, a negative acknowledgment indicating that the user equipment 115 does not have sufficient RLNC packets 220 to decode the packet ensemble 240, or combinations thereof.
If the packet ensemble 240 can be decoded, the processor 405 may communicate 645 decode feedback that indicates that the packet ensemble 240 can be decoded from the received k RLNC packets 220. The processor 405 may decode 655 the RLNC packets 220 and the method 600 ends. The processor 405 may calculate a coefficient matrix M comprising k encoding vectors [c1i, c2i, . . . cki] 210 of coefficients c. The coefficients may be randomly selected from the Galois field 205. The processor 405 may decode 655 the plurality of k RLNC packets using Equation 3, where pi are the data packets 215 and/or resized data packets 230, and M−1 is an inverse of the coefficient matrix M.

[p1,p2 . . . pk]=M−1·[r1,r2, . . . rk]T  Equation 3

The embodiments iteratively encode data packets 215 of a packet ensemble 240 into RLNC packets 220 and transmit PDU 255 generated from the RLNC packets 220 from the user equipment 115 to the network coding node 105 and/or reception point 110. Redundant RLNC packets 220 and/or PDU 255 may be transmitted. The network coding node 105 may extend the transfer matrix 330 with encoding vectors 210 from received RLNC packets 220 until the packet ensemble 240 may be decoded. Because the embodiments may continue to extend the transfer matrix 330 even if a PDU 255 is lost or if the RLNC packet 220 is not recovered, a decrease in transmission performance is mitigated. In addition, the reliability of the transmission is increased. As a result, higher wireless frequencies 125 and transmission rates may be employed with high reliability. In addition, two or more reception points 110 may reliably communicate with the user equipment 115.
Embodiments may be practiced in other specific forms. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

## Claims

1. A method comprising:
receiving, by use of a processor, a Galois field and a resource allocation for transmission of data from user equipment;
encoding a first set of k data packets from a first data ensemble into a first random linear network coded (RLNC) packet as a function of the Galois field, wherein the first RLNC packet comprises an ensemble number that identifies the first data ensemble, an encoding vector, and a sequence of RLNC sub-packets;
generating a first protocol data unit (PDU) that comprises a number of RLNC sub-packets of the first RLNC packet such that a size of the first PDU does not exceed the resource allocation; and
transmitting the PDU.

2. The method of claim 1, the method further comprising:
encoding a second set of k data packets from a second data ensemble into a second RLNC packet, wherein the second RLNC packet comprises a sequence of RLNC sub-packets; and
including in the first PDU a maximum number of RLNC sub-packets of the second RLNC packet such that the size of the first PDU does not exceed the resource allocation.

3. The method of claim 1 further comprising:
encoding the first set of k data packets from the first data ensemble into a second RLNC packet, wherein the second RLNC packet comprises a sequence of RLNC sub-packets; and
including in the first PDU, a maximum number of RLNC sub-packets of the second RLNC packet that can be included without the PDU exceeding the size of the resource allocation.

4. The method of claim 1, wherein RLNC sub-packets are allocated to the first PDU at a physical layer of a communication stack.

5. The method of claim 1, wherein encoding the plurality of at least k data packets comprises:
generating a coefficient vector comprising at least k encoding vectors [c1i, c2i, . . . cki] of coefficients randomly selected from the Galois field; and
encoding the plurality of at least k data packets p as the plurality of k RLNC packets y wherein each y is calculated as yi=Σi=1k ci pi.

6. The method of claim 1, wherein the first set of k data packets from the first ensemble are obtained by resizing a set of k original data packets by:
calculating a specified packet length l, wherein l is greater than or equal to a total number of sub-packets in the plurality of data packets divided by k; and
distributing sub-packets from long data packets with greater than l sub-packets to short data packets with less than l sub-packets.

7. The method of claim 6, the method further comprising appending null sub-packets to short data packets with less than l sub-packets.

8. The method of claim 6, where k is communicated to the user equipment by a network coding node and k is calculated as a function of a resource allocation and data traffic characteristics comprising one or more of packet arrival requirements and delay requirements.

9. The method of claim 1, wherein at least one data packet is encoded with two or more encoding vectors and transmitted to one or more reception points.

10. The method of claim 1, wherein the PDU is filled with one RLNC sub-packet from a plurality of data ensembles.

11. The method of claim 1, wherein the PDU is initially filled with RLNC sub-packets from the first RLNC packet and subsequently filled with RLNC sub-packets from a second RLNC packet.

12. The method of claim 1, where a first user equipment communicates the first data packet to a second user equipment over a device-to-device channel and the second user equipment communicates a second RLNC packet derived from at least the first data packet to a reception point.

13. The method of claim 12, wherein the second RLNC packet is derived from the first data packet and from other data packets present at the second user equipment.

14. The method of claim 12, wherein the first data packet is positioned within the second RLNC packet based on a pre-selection map.

15. The method of claim 1, wherein the PDU is transmitted from a first user equipment with increased power in response to communication over a device-to-device channel from a second user equipment that the second user equipment is communicating with a reception point that is not in communication with the first user equipment.

16. An apparatus comprising:
a processor performing:
receiving a Galois field and a resource allocation for transmission of data from user equipment;
encoding a first set of k data packets from a first data ensemble into a first random linear network coded (RLNC) packet as a function of the Galois field, wherein the first RLNC packet comprises an ensemble number that identifies the first data ensemble, an encoding vector, and a sequence of RLNC sub-packets;
generating a first protocol data unit (PDU) that comprises a number of RLNC sub-packets of the first RLNC packet such that a size of the first PDU does not exceed the resource allocation; and
transmitting the PDU.

17. The apparatus of claim 16, the processor further performing:
encoding a second set of k data packets from a second data ensemble into a second RLNC packet, wherein the second RLNC packet comprises a sequence of RLNC sub-packets; and
including in the first PDU a maximum number of RLNC sub-packets of the second RLNC packet such that the size of the first PDU does not exceed the resource allocation.