Abstract:
Transmission over a communication channel using carrier sense multiple access collision avoidance (CSMA/CA) may be performed by determining for each frame if the communication channel is busy after a backoff time proportional to a randomly generated number within a contention window (CW). When the channel is not busy, a frame of data may be transmitted. When the channel is busy, the device may periodically determine if the communication channel is busy after subsequent backoff times. The value of CW is adjusted for each subsequent backoff time using a fairness protocol, in which the value of CW is increased until the value of CW reaches a maximum CW value; and then the value of CW is held until a fairness number of backoff repetitions reaches a fairness threshold; then the value of CW is reduced incrementally until the value of CW reaches a minimum CW value.
Abstract:
Embodiments of the invention provide systems and methods for a cipher then segment approach in a Power Line Communication (PLC). A node or device generates frames to be transmitted to a destination node in the PLC network. A processor in the node is configured to generate a data payload comprising data to be sent to the destination node. The processor divides the data payload into two or more payload segments and encrypts the payload segments. The processor creates a frame for each of the encrypted payload segments, wherein each frame comprises a message integrity code. The processor creates a segment identifier for each frame using the message integrity code and an authentication key that is shared with the destination PLC node. The segment identifier is added to each frame.
Abstract:
Power Line Communications (PLC) device for enhanced carrier sense multiple access (CSMA) protocols are described. The PLC device includes a modem, an AC interface and a PLC engine. The engine is configured for transmitting PLC packets over a plurality of electrical wires using a particular channel. Transmitting a normal priority packet may include attempting to access a communications channel to transmit a frame after a backoff time proportional to a randomly generated number within a contention window (CW), the CW having an initial value carried over from a previous transmission of a different frame. Additionally or alternatively, some of techniques described herein may facilitate the spreading of the time over which devices attempt to transmit packets, thereby reducing the probability of collisions using, for example, Additive Decrease Multiplicative Increase (ADMI) mechanisms.
Abstract:
Systems and methods for routing protocols for power line communications (PLC) are described. In some embodiments, a method performed by a PLC device, such as a PLC meter, may include selecting one or more transmit sub-bands on which to transmit frames, where the transmit sub-bands comprise groups of carrier frequencies. The PLC device then generates a frame comprising a tone map that indicates which transmit sub-bands are used to carry data for the frame. The tone map using two bits per transmit sub-band to indicate a status of each transmit sub-band. The PLC device then transmits the frame on the selected transmit sub-bands. A resolution bit and a mode bit may be used to provide additional information about the transmit sub-bands, such as an amount of power adjustment that has been applied to carrier frequencies and whether dummy bits are transmitted on unused carrier frequencies.
Abstract:
Disclosed embodiments include a system having one or more member devices coupled to a network and a power line communication (PLC) device. The PLC device is configured to identify available bootstrapping agents that correspond to the one or more member devices, each available bootstrapping agent having a corresponding personal area network (PAN) identifier, identify a target network having a PAN identifier to join, select a target bootstrapping agent from available bootstrapping agents associated with the target PAN identifier to use for a join process with the target network, attempt to join the target network using the target bootstrapping agent, and when the attempt to join is successful, transmit and receive PLC signals over at least one power line associated with the target network using a particular frequency band and a modulation scheme.
Abstract:
Apparatus, systems, and methods disclosed herein operate to provide wireless communication between personal mobile communication (PMC) devices. An emulated wireless access point (AP) at a first PMC device (PMC1) establishes a first tunneled direct link setup (TDLS) session between a first station module (STA1) incorporated into the PMC1 and a second station module (STA2) incorporated into a second PMC device (PMC2). Following establishment of the TDLS session, the wireless AP is allowed to sleep; and most infrastructure management duties are handled by the STA1 during the session. PMC device battery charge may be conserved as a result. The emulated wireless AP may also establish a second TDLS link to a third station module (STA3) incorporated into a third PMC device (PMC3). The STA1 may then bridge data traffic flow between the STA2 and the STA3. Such bridging operation may enable communication between two PMC devices otherwise unable to decode data received from the other.
Abstract:
Method and apparatus for avoiding hidden node collisions in a communication network. A network communication device includes a packet transmitter. The packet transmitter is configured to subdivide a packet to be transmitted via a communication network into a plurality of segments based on the packet exceeding a predetermined maximum size, and to sequentially transmit the segments via the communication network. The packet transmitter is also configured to construct an acknowledgement packet responsive to reception of each segment of a packet received via the communication network. The acknowledgement packet includes a field indicating whether an additional segment of the packet is to be transmitted via the communication network. The packet transmitter is further configured to transmit the acknowledgement packet via the communication network.
Abstract:
Apparatus (and related methods) for a power line communication network include a processor configured to receive beacons over a communication interface. The processor determines a link quality indicator (LQI) for each received beacon and ignores the beacons for at most a predetermined maximum number of beacon receptions when each LQI is below a threshold. The processor responds to a received beacon if the LQI for such received beacon exceeds the threshold or if a predetermined maximum number of beacons have been received with LQIs below the threshold.
Abstract:
Systems and methods for enhanced carrier sense multiple access (CSMA) protocols are described. In various implementations, these systems and methods may be applicable to Power Line Communications (PLC). For example, a method may include attempting to access a communications channel to transmit a frame after a backoff time proportional to a randomly generated number within a contention window (CW), the CW having an initial value carried over from a previous transmission of a different frame. Additionally or alternatively, some of techniques described herein may facilitate the spreading of the time over which devices attempt to transmit packets, thereby reducing the probability of collisions using, for example, Additive Decrease Multiplicative Increase (ADMI) mechanisms.
Abstract:
Embodiments of methods and systems for supporting coexistence of multiple technologies in a Power Line Communication (PLC) network are disclosed. A long coexistence preamble sequence may be transmitted by a device that has been forced to back off the PLC channel multiple times. The long coexistence sequence provides a way for the device to request channel access from devices on the channel using other technology. The device may transmit a data packet after transmitting the long coexistence preamble sequence. A network duty cycle time may also be defined as a maximum allowed duration for nodes of the same network to access the channel. When the network duty cycle time occurs, all nodes will back off the channel for a duty cycle extended inter frame space before transmitting again. The long coexistence preamble sequence and the network duty cycle time may be used together.