Introduction to the media access control layer of the ultra-wideband wireless network

I have made a lot of introductions and descriptions in the previous articles on the ultra-wideband wireless network. Therefore, we must have some knowledge about the ultra-wideband wireless communication layer in the previous ultra-wideband wireless protocol. Next, we will continue to look at the media access control layer of the ultra-wideband wireless network.

Media Access Control Layer

The UWB wireless communication layer is responsible for RF processing, while the media access control layer is responsible for managing the UWB wireless network and controlling the wireless communication status. When several UWB wireless network devices are very close to each other, they constitute a so-called point-to-point Ad Hoc network. An Ad Hoc network is not a pre-planned network, but is constructed by a very close group of participating devices. Participating devices can join and exit as appropriate.

3 shows an Ad Hoc network built on three UWB devices. Device A is invisible to Device C. Device A (the device on the left in the figure) may know the existence of Device C and its occupied time slot even if it cannot "hear" Device C, because it can learn about Device C through the so-called beacon. The beacon stores information about neighboring devices, so devices can understand each other. Data may be transmitted directly between all devices that can receive information from each other in any direction.

Figure 1 device A knows the existence of Device C through Device B

The Time Division Multiple Access (TDMA) method is used to organize Transmission Based on Time slots and frames. The combination of time slots in the ultra-wideband wireless network constitutes a superframe (see figure 4 ). The superframe is divided into a standard segment (BP) and a data transmission segment (DTP ). Beacon and valid data occupy 256 Media Access time slots over frames. One media access time slot lasts 256 μs, and one ultra frame lasts 65.5 ms. All network members that can "listen" to each other synchronize with the superframe through the received beacon. The information in the beacon can be considered as the communication channel of the network member.

Figure 2 over-frame data in a UWB wireless network is divided into standard and transmission segments.