Mitsubishi Electric Corporation

Mitsubishi Electric Research Laboratories, Inc.

Mitsubishi Denki Kabushiki Kaisha

Yukimasa Nagai

Takenori Sumi

Philip Orlik

Jianlin Guo

Hiroyoshi Suga

Kieran Parsons

Pu Wang

Rui Ma

Daniel Antonio Da Costa Dinis

Shintaro Fujikami

Takahisa Yamauchi

Akinori Taira

Zhifeng Tao

Akinori Fujimura

Daqing Gu

Hiroaki Hirai

Yosuke Yokoyama

Ying Liu

Tetsuya Kosaka

Yosikatu Tajima

Mari Otiai

Shuai Wang

A computer-executed method is provided for IEEE 802.15.4 devices based on a suspendable carrier-sense multiple access with collision avoidance (CSMA/CA) control program and standard CSMA/CA control program for an IEEE 802.15.4 network composing of IEEE 802.15.4 devices. The computer-executed method is provided on an IEEE 802.15.4 device, and causes a processor of the IEEE 802.15.4 device to perform steps that include determining the permission of backoff suspension and the intention of IEEE 802.15.4 device to perform backoff suspension, selecting the suspendable CSMA/CA control program if the backoff suspension is permitted and IEEE 802.15.4 device intends to perform backoff suspension. The suspendable CSMA/CA control program is configured to perform active CCA within each unit backoff period and suspend backoff if channel is detected to be busy, performing a CCA when backoff completes, transmitting frame when the detected channel status is an idle state or incrementing a number of backoff (NB) when the detected channel status is an busy state, determining if a NB exceeds the macMaxCSMABackoffs, incrementing a number of retransmissions (NR) when a NB exceeds the macMaxCSMABackoffs, and discarding frame when a NR exceeds macMaxFrameRetries.

Suspendable CSMA/CA for IEEE 802.15.4 system to reduce packet discard caused by backoff failure

A wireless smart utility network (Wi-SUN) device is provided for coexistence with a Wi-Fi HaLow network sharing frequency spectra between the networks. The Wi-SUN device includes a receiver receiving packets of neighbor Wi-SUN devices, a memory storing computer executable programs including a hybrid carrier-sense multiple access with collision avoidance (CSMA/CA) control program and Wi-SUN backoff control program, a processor to execute steps of estimating a severity of Wi-Fi HaLow interference based on one or combination of the severity metrics, selecting a CSMA/CA mode between predetermined CSMA/CA modes in response to the estimated severity, detecting a channel status based on the hybrid carrier-sense multiple access, wherein if the channel status is not idle, a maximum limited number of times for re-attempting a packet transmission is checked to determine an allowability of re-attempting the packet transmission, and a transmitter to transmit packets according to a determination result of the allowability.

Hybrid carrier sense multiple access system with collision avoidance for IEEE 802.15.4 to achieve better coexistence with IEEE 802.11

A computer-implemented method is provided for discovering heterogenous neighbors in coexisting IoT networks including at least one Wi-Fi device and at least one of Zigbee coordinators, ZigBee routers and ZigBee end devices. The method includes generating a broadcast packet such that the broadcast packet emulates a ZigBee broadcast frame, transmitting the emulated broadcast packet using a transceiver of the at least one Wi-Fi device according to cross-technology communication (CTC) method, wherein the emulated broadcast packet is configured to trigger the at least one of the Zigbee coordinators and ZigBee routers having received the emulated broadcast packet to rebroadcast the received packet. The method also includes generating a unicast packet such that the unicast packet emulates a ZigBee address request frame, transmitting the emulated unicast packet using a transceiver of the at least one Wi-Fi device according to cross-technology communication (CTC) method, wherein the emulated unicast packet is configured to trigger the at least one of the Zigbee coordinators, ZigBee routers and ZigBee end devices having received the emulated unicast packet to respond with a ZigBee address response frame, and determining the at least one ZigBee end device to be a neighbor of the at least one Wi-Fi device if the scanned address response frame is transmitted by the at least one ZigBee end device.

Active cross-technology neighbor discovery

A computer-executed method is provided for IEEE 802.15.4 devices based on an active carrier sense based carrier-sense multiple access with collision avoidance (ACS-CSMA/CA) control program and standard CSMA/CA control program for coexistence of an IEEE 802.15.4 network composing of IEEE 802.15.4 devices and IEEE 802.11 network composing of IEEE 802.11 devices sharing frequency spectra between the networks. The computer-executed method is provided on an IEEE 802.15.4 device, and causes a processor of the IEEE 802.15.4 device to perform steps that include estimating a severity of IEEE 802.11 interference based on a severity estimation metric, selecting the ACS-CSMA/CA control program based on the estimated severity. The ACS-CSMA/CA control program is configured to perform dynamically updating a maximum number of backoffs (macMaxCSMABackoffs) based on the estimated severity,cdetermining if a number of backoffs (NB) exceeds the updated macMaxCSMABackoffs, performing consecutive CCA operation to continuously detect channel status, and transmitting frames when the detected channel status is an idle state or incrementing number of retransmissions (NR) when the detected channel status is a busy state.

System and method for active carrier sense based CSMA/CA for IEEE 802.15.4 system to avoid packet discard caused by interference

A wireless smart utility network (Wi-SUN) device participating in a Wi-SUN network for coexistence with a Wi-Fi HaLow network sharing frequency spectra between the networks is provided. The Wi-SUN device includes a receiver to receive packets of neighbor Wi-SUN devices, a memory configured to store computer executable programs including a hybrid carrier-sense multiple access with collision avoidance (CSMA/CA) control program and Wi-SUN backoff control program, a processor configured to execute the hybrid CSMA/CA control program including instructions that steps of estimating a severity of Wi-Fi Halow interference based on one or combination of the severity metrics, selecting a CSMA/CA mode between predetermined CSMA/CA modes in response to the estimated severity, detecting a channel status based on the hybrid carrier-sense multiple access, wherein if the channel status is not idle, a maximum limited number of times for re-attempting a packet transmission is checked to determine an allowability of re-attempting the packet transmission, and a transmitter to transmit packets according to a determination result of the allowability.

A node device for forming a multi-hop network is provided. The node device is configured to avoid interference from coexisting interfering networks and includes a transceiver configured to receive and transmit data with respect to a Destination Oriented Directed Acyclic Graph (DODAG) Information Object message (DIO message), a memory configured to store computer executable programs including an interfered-node count (IC), single-rate link count (SLC), multi-rate link count (MLC), hop count (HP), path communication latency (PCL) and an interference efficient and multi-rate supported routing program CoM-RPL, and a processor configured to perform steps of the computer executable programs. The steps include determining if the received DIO message indicates a new DODAG or an existing DODAG. In this case, if a determined result in the determining indicates the new DODAG and no single-rate link and no interfered node on a path of multi-hop network, the node device joins DODAG network and the processor selects a sender of the DIO message as a default parent, computes a rank for itself, updates DIO message with its rank, IC, SLC, TRM, HP, PCL and transmits scheduled DIO messages based on transmission rate mode.

Routing data in wireless network that coexists with interfering wireless networks

A wireless smart utility networks (Wi-SUN) device participating in a Wi-SUN network for coexistence with a Wi-Fi HaLow network sharing frequency spectra between the networks is disclosed. The Wi-SUN device includes a receiver to receive packets of neighbor Wi-SUN devices, a memory configured to store computer executable programs including a Hybrid carrier-sense multiple access (CSMA) control program and Wi-SUN Backoff control Program, a processor configured to execute the Hybrid CSMA control program, including instructions that cause the processor to perform steps of estimating a severity of Wi-Fi Halow interference based on a severity detection method, switching a backoff mode between predetermined backoff modes in response to the estimated severity, and performing a backoff procedure according to the selected backoff mode, and a transmitter to transmit packets.

A radio frequency (RF) transmitter includes a set of input ports to receive baseband samples of a signal to be transmitted on a set of disjoint frequency bands, a set of filter banks, there is one filter bank for each input port, each filter bank includes a plurality of digital polyphase interpolation filters to sample a shifted phase of the corresponding sequence of baseband samples and to interpolate the sampled phases to produce a plurality of sequences of interpolated baseband phased samples with the shifted phase, and a set of oscillators banks, each oscillator bank includes a plurality of polyphase Digital Direct Synthesizer (DDS) corresponding to the plurality of digital polyphase interpolation filters to generate a plurality of sequences of samples of digital waveform. The RF transmitter includes a set of mixer banks to mix corresponding sequences of samples of digital waveform and interpolated baseband phased samples to up convert each sequence of interpolated baseband phased samples to the effective frequency, a parallel digital combiner to combine in-phase sequences of interpolated baseband phased samples of different frequency bands to produce a plurality of sequences of multiband upconverted samples, and a pulse encoder to modulate and encode the plurality of sequences of multiband upconverted samples to produce a plurality of encoded multi-band signals. The RF transmitter converts the plurality of encoded multi-band signals into a RF bitstream and radiate the RF bitstream as an analog signal.

Mixed-mode millimeter-wave transmitter

System and method for generating high speed digitized-RF signals

A radio frequency (RF) transmitter includes a set of input ports to receive baseband, a set of filter banks for each input port that includes a plurality of digital polyphase interpolation filters, and a set of oscillators banks, wherein each oscillator bank includes a plurality of polyphase Digital Direct Synthesizer (DDS) corresponding to the plurality of digital polyphase interpolation filters. The RF transmitter includes a set of mixer banks to mix corresponding sequences of samples of digital waveform, a parallel digital combiner to combine in-phase sequences of interpolated baseband phased samples, and a pulse encoder to modulate and encode the plurality of sequences of multiband upconverted samples. The RF transmitter converts a plurality of encoded multi-band signals into a RF bitstream and an E/O interface to convert the RF bitstream.

High speed digital bit generator for optical frontal interface

A network system for coexistence of a Wi-Fi HaLow network and a low-rate wireless personal area network (LR-WPAN) includes a receiver for receiving a wireless signal of a frequency band shared with the LR-WPAN using an LR-WPAN protocol, a sensor for detecting an energy level of the wireless signal, a memory storing a first program for performing an energy-detection (ED) clear channel assignment (CCA) control process, a processor, in connection with the sensor and the memory, for executing the first program to determine if a transmission of a packet is permitted based on the detected energy level of the wireless signal according to the ED CCA control process, and a transmitter for transmitting the packet over the frequency band according to the Wi-Fi HaLow protocol when the ED CCA control process has permitted the transmission.

System for coexistence of Wi-Fi HaLow network and low-rate wireless personal area network (LR-WPAN)

A wireless communication deviceencrypts a passphrase which corresponds to a communication mode after change and which is a character string for authentication by using an encryption key PTK corresponding to a communication mode before change, and transmits the encrypted passphrase to a wireless communication device, and also creates an encryption key PTK corresponding to the communication mode after change from the passphrase corresponding to the communication mode after change. The wireless communication devicereceives the encrypted passphrase transmitted from the wireless communication deviceand decrypts the encrypted passphrase by using an encryption key PTK corresponding to the communication mode before change, and also creates an encryption key PTK corresponding to the communication mode after change from the decrypted passphrase.

Wireless communication system and wireless communication method

Each of wireless communication devicesA,B andC is configured in such a way as to transmit information about either a service or an application which the wireless communication device can provide, in accordance with a protocol which makes it possible to perform wireless communications with a wireless communication deviceregardless of the setting of a communication mode to the wireless communication device, and the wireless communication deviceis configured in such a way as to collect information about an application which is transmitted from each of the wireless communication devicesA,B andC. As a result, the wireless communication devicecan acquire the information about the providable application from each of the wireless communication devicesA,B andC existing in the surroundings thereof regardless of the setting of a communication mode.

A radio communication system includes a plurality of radio communication apparatuses including an active scan terminal and a passive scan terminal. After transmitting a probe request frame from one frequency channel, the active scan terminal continuously transmits the probe request frame from other frequency channels without waiting for a response frame from the other radio communication apparatuses, thereafter transmits the probe request frame from a response channel, which is a waiting channel, and waits for a response from the passive scan terminal, and superimposes, on the probe request frame, information concerning an offset time to the response and information concerning the response channel, and, after receiving the probe request frame, after the elapse of the offset time to the response, the passive scan terminal transmits a response frame from a frequency channel designated by the response channel information.

Growing community of inventors

Tokyo, Japan

Yukimasa Nagai