A method for multiple access to a frequency band of a communication channel of a communication network with carrier sensing and collision avoidance, including a division of the frequency band into a set of request-to-send sub-bands dedicated to the transmission, by source nodes to a destination node, of request-to-send messages for communicating data on the frequency band is provided. The method includes an evaluation of a communication channel load, and, as a function of the result of the evaluation, a re-division of the frequency band to modify the number of sub-bands of the set of request-to-send sub-bands.

A first wireless communication user equipment (UE) device transmits a device-to device (D2D) Sounding Reference Signal (SRS) to a second wireless communication (UE) device using microcell communication resources. The second wireless communication (UE) device evaluates the SRS to discover the first wireless communication (UE) device, estimate channel conditions, and/or determine Channel State Information. Information indicative of the CSI is reported to a base station. Based on the reported channel conditions, (D2D) communication resources are scheduled by assigning microcell communication resources to the wireless communication (UE) devices.

Macrocell communication resources are assigned for device-to-device (D2D) communication between two wireless communication user equipment (UE) devices. A scheduler in a communication system schedules (assigns) scheduled downlink communication resources for downlink transmission of signals from a base station, schedules (assigns) scheduled uplink communication resources for uplink communication from wireless communication UE devices to base stations, and schedules (assigns) D2D communication resources for D2D communication between wireless communication UE devices. The D2D communication resources are selected from either defined downlink communication resources or defined uplink communication resources that are defined by communication specification. The base station sends communication resource allocation (CRA) information to at least one of the wireless communication UE devices where the communication resource allocation information identifies the D2D communication resources for use by the wireless communication UE devices to communicate through a device-to-device (D2D) communication link.

A transmitter, a receiver and methods therein, configured to transmit a first type of synchronisation signal, in M.sub.1 symbols l.sub.i,, 0i(M.sub.11) and a second type of synchronisation signal in M.sub.2 symbols k.sub.j,, 0j(M.sub.21) of a subframe , wherein M.sub.2M.sub.12. The transmitter comprises a processor, configured to determine in which symbols l.sub.i the synchronisation signal of the first type is to be transmitted, and in addition configured to calculate in which symbols k.sub.j, the synchronisation signal of the second type is to be transmitted, by placing each of the M.sub.2 symbols k.sub.j at a symbol distance from an associated symbol l.sub.i. The transmitter also comprises a transmitting circuit configured to transmit the synchronisation signals of the first type in the M.sub.1 symbols l.sub.i, and transmitting the synchronisation signals of the second type in the M.sub.2 symbols k.sub.j.

A wireless cellular device comprises physical layer circuitry configured to transmit and receive radio frequency electrical signals to communicate directly with one or more separate wireless devices using a communication channel of a cellular network and a WiFi communication channel of a WiFi communication spectrum; and processing circuitry configured to initiate transmission of a WiFi subframe via the WiFi communication channel to reserve communication time on the WiFi communication channel for use by the same or a different cellular device during the reserved communication time.

In a wireless communication system comprising at least one evolved Node-B (eNB) and a plurality of wireless transmit/receive units (WTRUs), a non-contention based (NCB) channel is established, maintained, and utilized. The NCB channel is allocated for use by one or more WTRUs in the system for utilization in a variety of functions, and the allocation is communicated to the WTRUs. The wireless communication system analyzes the allocation of the NCB channel as required, and the NCB channel is reallocated as required.

Devices, systems and methods for operating a rear-facing perception system for vehicles are described. An exemplary rear-facing perception system contains two corner units and a center unit, with each of the two corner units and the center unit including a camera module and a dual-band transceiver. A method for operating the rear-facing perception system includes pairing with a control unit by communicating, using the dual-band transceiver, over at least a first frequency band, transmitting a first trigger signal to the two corner units over a second frequency band non-overlapping with the first frequency band, and switching to an active mode. In an example, the first trigger signal causes the two corner units to switch to the active mode, which includes orienting the camera modules on the center unit and the two corner units to provide an unobstructed view of an area around a rear of the vehicle.

In a wireless communication system comprising at least one evolved Node-B (eNB) and a plurality of wireless transmit/receive units (WTRUs), a non-contention based (NCB) channel is established, maintained, and utilized. The NCB channel is allocated for use by one or more WTRUs in the system for utilization in a variety of functions, and the allocation is communicated to the WTRUs. The wireless communication system analyzes the allocation of the NCB channel as required, and the NCB channel is reallocated as required.

Aspects of this disclosure relate to a front end architecture for selectively adding an external carrier aggregation band. A switch element can connect a radio frequency signal path to an antenna path through a frequency domain multiplexer, such as a diplexer, in a first mode. The switch element can connect the radio frequency path to the antenna path and bypass the frequency domain multiplexer in a second mode. The frequency domain multiplexer can be external to a front end module that include the radio frequency signal path. In the first mode, a front end system can support carrier aggregation with a band associated with circuitry implemented external to the front end module.