China
Africa
Explore chapters and articles related to this topic
Wireless LAN Technology for the Factory Floor: Challenges and Approaches
Published in Richard Zurawski, Networked Embedded Systems, 2017
The distributed WMAC protocol uses a CSMA/CA (carrier-sense-multiple-access with collision avoidance) scheme with priority-dependent backoffs. A station wishing to transmit a packet uses a carrier-sense mechanism to wait for the end of an ongoing packet transmission. After this, the station picks a backoff time depending on the priority value of the current packet. The station listens on the channel during the backoff time. If no other station starts transmission, the station assumes that it has the highest priority and starts transmitting its own packet. Otherwise, the station defers and starts over after the other packet has been finished. In another distributed scheme, the CAN message priority value is mapped onto the channel using an on–off keying scheme [41]. A station transmits a short burst if the current priority bit is a logical one, otherwise it switches into receive mode. If the station receives any signal it gives up, otherwise it continues with the next bit. The priority bits are considered from the most significant bit to the least significant bit. If the station is still contending after the last bit, it transmits the actual data packet. This approach requires tight synchronization and fast switching between transmit and receive modes of the radio transceiver, which is a problem for certain WLAN technologies.
Wireless LAN Technology for the Factory Floor: Challenges and Approaches
Published in Richard Zurawski, Industrial Communication Technology Handbook, 2017
The distributed WMAC protocol uses the scheme CSMA with collision avoidance (CSMA/CA) with priority-dependent backoffs. A station wishing to transmit a packet uses a carrier sense mechanism to wait for the end of an ongoing packet transmission. After this, the station picks a backoff time depending on the priority value of the current packet. The station listens to the channel during the backoff time. If no other station starts transmission, the station assumes that it has the highest priority and starts transmitting its own packet. Otherwise, the station defers and starts over after the other packet has been finished. In another distributed scheme, the CAN message priority value is mapped onto the channel using an on–off keying scheme [60]. A station transmits a short burst if the current priority bit is a logical one; otherwise, it switches into receive mode. If the station receives any signal, it gives up; otherwise, it continues with the next bit. The priority bits are considered from the most significant bit to the least significant bit. If the station is still contending after the last bit, it transmits the actual data packet. This approach requires tight synchronization and fast switching between transmit and receive modes of the radio transceiver, which is a problem for certain WLAN technologies. A similar scheme has also been proposed in [82].
Performance engineering for HEVC transform and quantization kernel on GPUs
Published in Automatika, 2020
Mate Čobrnić, Alen Duspara, Leon Dragić, Igor Piljić, Mario Kovač
AZB identification is the last stage in the process. The information if all levels coming out from one TB are zero is used to set the value of the syntax element coded block flag (CBF). This helps to reduce the number of bits to be transmitted.