WO2012078785A2 - Protocoles d'accès multiple avec écoute de porteuse (csma) pour les courants porteurs en ligne (plc) - Google Patents

Protocoles d'accès multiple avec écoute de porteuse (csma) pour les courants porteurs en ligne (plc) Download PDF

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Publication number
WO2012078785A2
WO2012078785A2 PCT/US2011/063786 US2011063786W WO2012078785A2 WO 2012078785 A2 WO2012078785 A2 WO 2012078785A2 US 2011063786 W US2011063786 W US 2011063786W WO 2012078785 A2 WO2012078785 A2 WO 2012078785A2
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WO
WIPO (PCT)
Prior art keywords
sensing operation
carrier sensing
plc
physical carrier
contention window
Prior art date
Application number
PCT/US2011/063786
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English (en)
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WO2012078785A3 (fr
Inventor
Shu Du
Robert Liang
Xiaolin Lu
Original Assignee
Texas Instruments Incorporated
Texas Instruments Japan Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US13/300,812 external-priority patent/US8711873B2/en
Application filed by Texas Instruments Incorporated, Texas Instruments Japan Limited filed Critical Texas Instruments Incorporated
Priority to JP2013543320A priority Critical patent/JP5964317B2/ja
Priority to CN201180058791.8A priority patent/CN103250354B/zh
Publication of WO2012078785A2 publication Critical patent/WO2012078785A2/fr
Publication of WO2012078785A3 publication Critical patent/WO2012078785A3/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/54—Systems for transmission via power distribution lines
    • H04B3/542—Systems for transmission via power distribution lines the information being in digital form
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B2203/00—Indexing scheme relating to line transmission systems
    • H04B2203/54—Aspects of powerline communications not already covered by H04B3/54 and its subgroups
    • H04B2203/5404—Methods of transmitting or receiving signals via power distribution lines
    • H04B2203/5408—Methods of transmitting or receiving signals via power distribution lines using protocols
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B2203/00—Indexing scheme relating to line transmission systems
    • H04B2203/54—Aspects of powerline communications not already covered by H04B3/54 and its subgroups
    • H04B2203/5404—Methods of transmitting or receiving signals via power distribution lines
    • H04B2203/5416—Methods of transmitting or receiving signals via power distribution lines by adding signals to the wave form of the power source

Definitions

  • Embodiments are directed, in general, to power line communications (PLC), and, more specifically, to carrier sense multiple access (CSMA) protocols for PLC.
  • PLC power line communications
  • CSMA carrier sense multiple access
  • Power line communications include systems for communicating data over the same medium (i.e., a wire or conductor) that is also used to transmit electric power to residences, buildings, and other premises.
  • PLC systems may enable a wide array of applications, including, for example, automatic meter reading and load control (i.e., utility- type applications), automotive uses (e.g., charging electric cars), home automation (e.g., controlling appliances, lights, etc.), and/or computer networking (e.g., Internet access), to name only a few.
  • PLC Physical Downlink Control
  • PRIME Powerline Intelligent Metering Evolution
  • ITU-T G.hn ITU-T G.hn (e.g., G.9960 and G.9961) specifications.
  • a method may include performing a virtual carrier sensing operation and, in response to the virtual carrier sensing operation indicating that a communication channel is idle, calculating a contention window. The method may also include performing a physical carrier sensing operation subsequent to the virtual carrier sensing operation, the physical carrier sensing operation based, at least in part, upon the contention window. Then, in response to the physical carrier sensing operation indicating that the communication channel is idle, the method may include transmitting data over the channel.
  • CSMA carrier sense multiple access
  • PLC power line communications
  • calculating the contention window may include setting a length of the contention window, and the physical carrier sensing operation may be carried out at a randomly selected time within the contention window. Also, the method may include repeating the virtual carrier sensing operation until it indicates that the communication channel is idle.
  • the method may include, in response to the physical carrier sensing operation indicating that the communication channel is not idle, repeating the virtual carrier sensing operation until it indicates that the communication channel is idle and increasing the length of the contention window to create a modified contention window. For instance, increasing the length of the contention window may include increasing the length of the contention window by an amount corresponding to a number of previous attempts to transmit the data.
  • the method may also include performing a second physical carrier sensing operation subsequent to the repeated virtual carrier sensing operation, the second physical carrier sensing operation based, at least in part, upon the modified contention window. For example, the second physical carrier sensing operation may be carried out at a randomly selected time within the modified contention window.
  • the method may further include, in response to the second physical carrier sensing operation indicating that the communication channel is idle, transmitting data over the communication channel.
  • a method may include: (a) in response to a virtual carrier sense operation indicating that an access channel is free, performing a physical carrier sensing operation based, at least in part, upon an original time window; (b) in response to the physical carrier sensing operation indicating that the access channel is free, initiating a data transmission over the access channel; (c) in response to the data transmission being a unicast transmission and an acknowledgment message not being received by the PLC device, incrementing a backoff counter and increasing the original time window; and (d) in response to the backoff counter having a value smaller than a maximum number of allowed backoff operations, repeating at least (a) and (b) using the increased time window.
  • increasing the original time window may include increasing a length of the original time window.
  • the physical carrier sensing operation may be performed at a randomly selected time within the original time window, and the repeated physical carrier sensing operation may be performed at a randomly selected time within the incremented time window.
  • the method may include monitoring an output of the virtual carrier sensing operation until it indicates that the access channel is free. Additionally or alternatively, the method may include, in response to the physical carrier sensing operation indicating that the access channel is busy, increasing the backoff counter, maintaining the original time window, and performing a second physical carrier sensing operation subsequent to a second virtual carrier sensing operation, the second physical carrier sensing operation based, at least in part, upon the original time window. For example, the second physical carrier sensing operation may be carried out at a randomly selected time within the original time window. The method may also include in response to the second physical carrier sensing operation indicating that the access channel is free, transmitting data over the access channel.
  • the method may include transmitting data at a time selected within a contention window in response to a determination by a carrier sense operation that a channel is available.
  • the method may also include determining that the data transmission is a unicast transmission, determining that an acknowledgement message has not been received, and increasing the contention window.
  • the method may further include retransmitting the data at a time selected within the increased contention window.
  • the method may also include re-transmitting the data in response to another determination by a repeated carrier sense operation that the channel is available.
  • the carrier sense operation may be a virtual carrier sense operation, a physical carrier sense operation, or a combination of physical and virtual carrier sense operations.
  • one or more of the methods described herein may be performed by one or more PLC devices (e.g., a PLC modem, etc.).
  • a tangible electronic storage medium may have program instructions stored thereon that, upon execution by a processor within one or more PLC devices, cause the one or more PLC devices to perform one or more operations disclosed herein.
  • Examples of such a processor include, but are not limited to, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a system-on-chip (SoC) circuit, a field-programmable gate array (FPGA), a microprocessor, or a microcontroller.
  • a PLC device may include at least one processor and a memory coupled to the at least one processor, the memory configured to store program instructions executable by the at least one processor to cause the PLC device to perform one or more operations disclosed herein.
  • FIG. 1 is a diagram of a PLC system according to some embodiments.
  • FIG. 2 is a block diagram of a PLC device or modem according to some embodiments.
  • FIG. 3 is a block diagram of a PLC gateway according to some embodiments.
  • FIG. 4 is a block diagram of a PLC data concentrator according to some embodiments.
  • FIG. 5 is a flowchart of a prior art CSMA technique.
  • FIG. 6 is a flowchart of a CSMA technique according to some embodiments.
  • FIG. 7 is a block diagram of an integrated circuit according to some embodiments.
  • FIG. 1 a power line communication (PLC) system is depicted according to some embodiments.
  • Medium voltage (MV) power lines 103 from substation 101 typically carry voltage in the tens of kilovolts range.
  • Transformer 104 steps the MV power down to low voltage (LV) power on LV lines 105, carrying voltage in the range of 100 - 240 VAC.
  • Transformer 104 is typically designed to operate at very low frequencies in the range of 50-60 Hz.
  • Transformer 104 does not typically allow high frequencies, such as signals greater than 100 KHz, to pass between LV lines 105 and MV lines 103.
  • LV lines 105 feed power to customers via meters 106a-n, which are typically mounted on the outside of residences 102a-n.
  • premises 102a-n may include any type of building, facility or location where electric power is received and/or consumed.
  • a breaker panel such as panel 107, provides an interface between meter 106n and electrical wires 108 within residence 102n.
  • Electrical wires 108 deliver power to outlets 110, switches 111 and other electric devices within residence 102n.
  • the power line topology illustrated in FIG. 1 may be used to deliver high-speed communications to residences 102a-n.
  • power line communications modems or gateways 112a-n may be coupled to LV power lines 105 at meter 106a-n.
  • PLC modems/gateways 112a-n may be used to transmit and receive data signals over MV/LV lines 103/105.
  • Such data signals may be used to support metering and power delivery applications (e.g., smart grid applications), communication systems, high speed Internet, telephony, video conferencing, and video delivery, to name a few.
  • An illustrative method for transmitting data over power lines may use a carrier signal having a frequency different from that of the power signal.
  • the carrier signal may be modulated by the data, for example, using an orthogonal frequency division multiplexing (OFDM) scheme or the like.
  • OFDM orthogonal frequency division multiplexing
  • PLC modems or gateways 112a-n at residences 102a-n use the MV/LV power grid to carry data signals to and from PLC data concentrator 114 without requiring additional wiring.
  • Concentrator 114 may be coupled to either MV line 103 or LV line 105.
  • Modems or gateways 112a-n may support applications such as high-speed broadband Internet links, narrowband control applications, low bandwidth data collection applications, or the like. In a home environment, for example, modems or gateways 112a-n may further enable home and building automation in heat and air conditioning, lighting, and security.
  • PLC modems or gateways 112a-n may enable AC or DC charging of electric vehicles and other appliances.
  • An example of an AC or DC charger is illustrated as PLC device 113. Outside the premises, power line communication networks may provide street lighting control and remote power meter data collection.
  • One or more concentrators 114 may be coupled to control center 130 (e.g., a utility company) via network 120.
  • Network 120 may include, for example, an IP-based network, the Internet, a cellular network, a WiFi network, a WiMax network, or the like.
  • control center 130 may be configured to collect power consumption and other types of relevant information from gateway(s) 112 and/or device(s) 113 through concentrator(s) 114.
  • control center 130 may be configured to implement smart grid policies and other regulatory or commercial rules by communicating such rules to each gateway(s) 112 and/or device(s) 113 through concentrator(s) 114.
  • FIG. 2 is a block diagram of PLC device 113 according to some embodiments.
  • AC interface 201 may be coupled to electrical wires 108a and 108b inside of premises 112n in a manner that allows PLC device 113 to switch the connection between wires 108a and 108b off using a switching circuit or the like. In other embodiments, however, AC interface 201 may be connected to a single wire 108 (i.e., without breaking wire 108 into wires 108a and 108b) and without providing such switching capabilities. In operation, AC interface 201 may allow PLC engine 202 to receive and transmit PLC signals over wires 108a-b. In some cases, PLC device 113 may be a PLC modem.
  • PLC device 1 13 may be a part of a smart grid device (e.g., an AC or DC charger, a meter, etc.), an appliance, or a control module for other electrical elements located inside or outside of premises 112n (e.g., street lighting, etc.).
  • a smart grid device e.g., an AC or DC charger, a meter, etc.
  • an appliance e.g., a meter, etc.
  • a control module for other electrical elements located inside or outside of premises 112n e.g., street lighting, etc.
  • PLC engine 202 may be configured to transmit and/or receive PLC signals over wires 108a and/or 108b via AC interface 201 using a particular frequency band.
  • PLC engine 202 may be configured to transmit OFDM signals, although other types of modulation schemes may be used.
  • PLC engine 202 may include or otherwise be configured to communicate with metrology or monitoring circuits (not shown) that are in turn configured to measure power consumption characteristics of certain devices or appliances via wires 108, 108a, and/or 108b.
  • PLC engine 202 may receive such power consumption information, encode it as one or more PLC signals, and transmit it over wires 108, 108a, and/or 108b to higher-level PLC devices (e.g., PLC gateways 112n, data aggregators 114, etc.) for further processing. Conversely, PLC engine 202 may receive instructions and/or other information from such higher-level PLC devices encoded in PLC signals, for example, to allow PLC engine 202 to select a particular frequency band in which to operate.
  • higher-level PLC devices e.g., PLC gateways 112n, data aggregators 114, etc.
  • FIG. 3 is a block diagram of PLC gateway 112 according to some embodiments.
  • gateway engine 301 is coupled to meter interface 302, local communication interface 304, and frequency band usage database 304.
  • Meter interface 302 is coupled to meter 106
  • local communication interface 304 is coupled to one or more of a variety of PLC devices such as, for example, PLC device 113.
  • Local communication interface 304 may provide a variety of communication protocols such as, for example, ZIGBEE,
  • gateway engine 301 may be configured to collect communications from PLC device 113 and/or other devices, as well as meter 106, and serve as an interface between these various devices and PLC data concentrator 114. Gateway engine 301 may also be configured to allocate frequency bands to specific devices and/or to provide information to such devices that enable them to self-assign their own operating frequencies.
  • PLC gateway 112 may be disposed within or near premises 102n and serve as a gateway to all PLC communications to and/or from premises 102n. In other embodiments, however, PLC gateway 112 may be absent and PLC devices 113 (as well as meter 106n and/or other appliances) may communicate directly with PLC data concentrator 114. When PLC gateway 112 is present, it may include database 304 with records of frequency bands currently used, for example, by various PLC devices 113 within premises 102n. An example of such a record may include, for instance, device identification information (e.g., serial number, device ID, etc.), application profile, device class, and/or currently allocated frequency band. As such, gateway engine 301 may use database 304 in assigning, allocating, or otherwise managing frequency bands assigned to its various PLC devices.
  • device identification information e.g., serial number, device ID, etc.
  • FIG. 4 is a block diagram of a PLC data concentrator according to some embodiments.
  • Gateway interface 401 is coupled to data concentrator engine 402 and may be configured to communicate with one or more PLC gateways 112a-n.
  • Network interface 403 is also coupled to data concentrator engine 402 and may be configured to communicate with network 120.
  • data concentrator engine 402 may be used to collect information and data from multiple gateways 112a-n before forwarding the data to control center 130.
  • gateway interface 401 may be replaced with a meter and/or device interface (now shown) configured to communicate directly with meters 116a-n, PLC devices 113, and/or other appliances.
  • frequency usage database 404 may be configured to store records similar to those described above with respect to database 304.
  • a PLC device may attempt to detect whether a given communication or access channel (e.g., frequency band) is currently in use.
  • Channel access may be accomplished, for example, by using the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) mechanism with a random backoff time.
  • CSMA/CA Carrier Sense Multiple Access with Collision Avoidance
  • the random backoff mechanism may spread the time over which PLC devices attempt to transmit, thereby reducing the probability of collision. In other words, each time a device wishes to transmit data frames, it may wait for a random period. If the channel is found to be idle or free, following the random backoff, the device may transmit its data. If the channel is found to be busy, following the random backoff, the device may wait for another random period before trying to access the channel again.
  • CSMA techniques may be employed.
  • PCS physical carrier sense
  • PHY physical layer
  • VCS virtual carrier sense
  • MAC media access control
  • VCS may be provided by a media access control (MAC) layer by tracking the expected duration of channel occupancy.
  • Virtual carrier sense may be set, for example, by the length of received packet (or upon collision).
  • VCS tracks or estimates the expected duration of the "busy" state of the medium (i.e., when a given PLC device is transmitting data over power lines or wires 103, 105, and/or 108).
  • FIG. 5 shows a flowchart of a prior art CSMA method that may be applicable, for instance, to a non-beacon personal area network (PAN) as described in the IEEE 802.15.4 standard.
  • PAN personal area network
  • a random backoff mechanism spreads the time over which stations attempt to transmit (thereby reducing the probability of collision).
  • This CSMA algorithm is typically used before the transmission of data or MAC command frames, and it is implemented using units of time called "backoff periods," where one backoff period is equal to
  • each device may maintain two variables for each transmission attempt: NB and BE.
  • NB is the number of times the CSMA algorithm was required to backoff while attempting the current transmission, which may be initialized to "0" before each new transmission attempt.
  • BE is the backoff exponent, which is related to how many backoff periods a device shall wait before attempting to assess a channel and which may be initialized to the value of minBE.
  • the method may initialize NB and BE and then proceed to block 502.
  • the method may create a delay, for a random number of complete backoff periods (e.g., in the range 0 to 2 BE -1), and then request that a PCS operation be performed in block 503.
  • the method may increment both NB and BE by one in block 506, while ensuring that BE does not exceed maxBE (for high priority packets, maxBE may be equal to minBE).
  • the method may return to block 502. If the value of NB is greater than maxCSMABackoffs, the method shall terminate, for example, with a channel access failure status or indication.
  • the method may immediately begin transmission of the frame at block 505.
  • PCS is sensed prematurely.
  • Each PCS interval is calculated independently of a VCS sensing result. If one node is sending a large packet, the competing node may fail easily due to unnecessary PCS trials. Additionally or alternatively, contention window increases prematurely. Every time PCS is busy, the BE is increased. Thus, if a node fails the first time of PCS, it then has a higher chance than the others to fail the following PCS due to its increased window, creating unfairness problems.
  • embodiments discussed herein provide techniques for using one or more VCS operations to save one or more unnecessary PCS operations.
  • the contention window may be increased when an ACK message or package is lost, thus differentiating a collision event from detection of a busy medium.
  • the techniques discussed herein may be applied in PLC mesh networks with random medium access, although other types of networks may also be used.
  • these embodiments may be used with various PLC standards, such as, for example, the G3-PLC standard or the like.
  • FIG. 6 a flowchart of a CSMA method is depicted according to some embodiments.
  • the method of FIG. 6 may be performed, for example, by PLC device 103, PLC gateway 112, and/or PLC data concentrator 114.
  • PLC device 103 PLC gateway 112
  • PLC data concentrator 114 PLC data concentrator 114
  • the method may include setting one or more backoff parameters (e.g., an NB counter and/or BE) to their initial values.
  • the method may perform a VCS operation, for example, until the VCS operation determines that a communication channel is idle or free.
  • the method may create a delay and request that a PCS operation be performed similarly as in blocks 501 and 502 of FIG. 5.
  • PCS is tried when VCS (virtual carrier sensing) is not busy. That is, VCS is consulted before PCS.
  • VCS When VCS becomes idle from a busy state, all the nodes (i.e., PLC devices) may be aligned at the same time for a fair competition for the channel. As such, both VCS and PCS may be used, and VCS saves the unnecessary PCS so that CSMA does not fail, for example, due to large packet transmission.
  • the method may determine whether the channel is idle or free based on the PCS operation. If so, the method may send data over the channel at block 606.
  • the method may determine whether the data transmission is a broadcast or a unicast transmission (the latter involves receiving an acknolwedgement message in response to a successful transmission, whereas the former does not). If the data transmission is a unicast transmission, the method may determine whether an acknowledgement has been received at block 608. If the data transmission is a broadcast transmission or if an acknowledgement has been received for a unicast transmission, the method may end with a success indication.
  • both NB and BE may be incremented.
  • BE may be increased if an acknowledgment (ACK) message or packet is not received (in the case of a unicast transmission).
  • ACK acknowledgment
  • PCS returns idle
  • a data frame may be sent out. Otherwise, the method may wait for the VCS to finish and BE remains the same value.
  • BE is increased.
  • the node or device may not increase its contention window so that all the nodes can have a fair CSMA competition. That is, only after an ACK is lost, thus suggesting a possible packet collision and crowded medium, may the node increase the contention window to compete with other devices for use of the channel.
  • channel condition may be bad, in which case the sender may try to transmit again without increasing the contention window size.
  • a sender and a receiver may interact with each other regarding the (past) lost ACK using extra bits in NACK (if NACK is able to be sent) or some additional exchange of information. The receiver may use the information to help the sender(s) differentiate the bad channel condition from the packet collision, so that the sender may respond differently when an ACK is lost. Additionally or alternatively, a receiver may also warn a sender about the bad channel using extra bits in the ACK packet if the receiver found the received packet has a low link quality indicator (LQI).
  • LQI low link quality indicator
  • FIG. 7 is a block diagram of an integrated circuit according to some embodiments.
  • integrated circuit 702 may be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a system-on- chip (SoC) circuit, a field-programmable gate array (FPGA), a microprocessor, a
  • DSP digital signal processor
  • ASIC application specific integrated circuit
  • SoC system-on- chip
  • FPGA field-programmable gate array
  • microprocessor a microprocessor
  • Integrated circuit 702 is coupled to one or more peripherals 704 and external memory 703.
  • external memory 703 may be used to store and/or maintain databases 304 and/or 404 shown in FIGS. 3 and 4.
  • integrated circuit 702 may include a driver for communicating signals to external memory 703 and another driver for communicating signals to peripherals 704.
  • Power supply 701 is also provided which supplies the supply voltages to integrated circuit 702 as well as one or more supply voltages to memory 703 and/or peripherals 704. In some embodiments, more than one instance of integrated circuit 702 may be included (and more than one external memory 703 may be included as well).
  • Peripherals 704 may include any desired circuitry, depending on the type of PLC system.
  • peripherals 704 may implement local communication interface 303 and include devices for various types of wireless communication, such as WI-FI, ZIGBEE, BLUETOOTH, cellular, global positioning system, etc.
  • Peripherals 704 may also include additional storage, including RAM storage, solid-state storage, or disk storage.
  • peripherals 704 may include user interface devices such as a display screen, including touch display screens or multi-touch display screens, keyboard or other input devices, microphones, speakers, etc.
  • External memory 703 may include any type of memory.
  • external memory 703 may include SRAM, nonvolatile RAM (NVRAM, such as “flash” memory), and/or dynamic RAM (DRAM) such as synchronous DRAM (SDRAM), double data rate (DDR, DDR2, DDR3, etc.) SDRAM, DRAM, etc.
  • External memory 703 may include one or more memory modules to which the memory devices are mounted, such as single inline memory modules (SIMMs), dual inline memory modules (DIMMs), etc.
  • SIMMs single inline memory modules
  • DIMMs dual inline memory modules
  • the modules shown in FIGS. 2-4 may represent sets of software routines, logic functions, and/or data structures that are configured to perform specified operations. Although these modules are shown as distinct logical blocks, in other embodiments at least some of the operations performed by these modules may be combined in to fewer blocks. Conversely, any given one of the modules shown in FIGS. 2-4 may be implemented such that its operations are divided among two or more logical blocks. Moreover, although shown with a particular configuration, in other embodiments these various modules may be rearranged in other suitable ways.
  • processor-readable, computer-readable, or machine-readable medium may include any device or medium that can store or transfer information. Examples of such a processor-readable medium include an electronic circuit, a semiconductor memory device, a flash memory, a ROM, an erasable ROM (EROM), a floppy diskette, a compact disk, an optical disk, a hard disk, a fiber optic medium, etc.
  • Software code segments may be stored in any volatile or non- volatile storage device, such as a hard drive, flash memory, solid state memory, optical disk, CD, DVD, computer program product, or other memory device, that provides tangible computer-readable or machine-readable storage for a processor or a middleware container service.
  • a volatile or non- volatile storage device such as a hard drive, flash memory, solid state memory, optical disk, CD, DVD, computer program product, or other memory device, that provides tangible computer-readable or machine-readable storage for a processor or a middleware container service.
  • the memory may be a virtualization of several physical storage devices, wherein the physical storage devices are of the same or different kinds.
  • the code segments may be downloaded or transferred from storage to a processor or container via an internal bus, another computer network, such as the Internet or an intranet, or via other wired or wireless networks.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne des systèmes et des procédés destinés aux protocoles d'accès multiple avec écoute de porteuse (CSMA) pour les courants porteurs en ligne (PLC). Un procédé peut comprendre la réalisation d'une opération d'écoute de porteuse virtuelle (VCS), et, lorsque cette opération d'écoute de porteuse virtuelle indique qu'un canal de communication est au repos, le calcul d'une fenêtre de collision (602). Ce procédé peut également comprendre la réalisation d'une opération d'écoute de porteuse physique (PCS) suite à l'opération d'écoute de porteuse virtuelle, ladite opération d'écoute de porteuse physique étant basée, au moins en partie, sur la fenêtre de collision (604). Lorsque l'opération d'écoute de porteuse physique indique que le canal de communication est au repos, ledit procédé peut comprendre alors la transmission de données par le biais de ce canal (606). Un autre procédé peut consister à déterminer qu'une transmission est une transmission individuelle et qu'aucun message d'accusé de réception (ACK) n'a été reçu (607, 608). Ce procédé peut consister en outre à incrémenter un paramètre de réduction de puissance (609) et à réaliser à nouveau une ou plusieurs opérations d'écoute de porteuse (602, 604).
PCT/US2011/063786 2010-12-07 2011-12-07 Protocoles d'accès multiple avec écoute de porteuse (csma) pour les courants porteurs en ligne (plc) WO2012078785A2 (fr)

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Application Number Priority Date Filing Date Title
JP2013543320A JP5964317B2 (ja) 2010-12-07 2011-12-07 電力線通信（ｐｌｃ）のためのキャリア検知多重アクセス（ｃｓｍａ）プロトコル
CN201180058791.8A CN103250354B (zh) 2010-12-07 2011-12-07 用于电力线通信(plc)的载波侦听多路访问(csma)协议

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US42041410P 2010-12-07 2010-12-07
US61/420,414 2010-12-07
US201061424159P 2010-12-17 2010-12-17
US61/424,159 2010-12-17
US13/300,812 2011-11-21
US13/300,812 US8711873B2 (en) 2010-12-17 2011-11-21 Carrier sense multiple access (CSMA) protocols for power line communications (PLC)

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