First IEEE802.11af-compatible baseband IC for TV white-space LANs
This prototype IC conforms to IEEE802.11af, which is the international standard for WLAN systems in the TV white-space spectrum. In addition, NICT has successfully prototyped a card-type communication device in an all-in-one package including an antenna. This card-type device can be driven by USB power and operated by inserting it into the USB port of an off-the-shelf PC.
From the viewpoint of effective use of limited spectrum resources, TV white-space (TVWS) utilization has been studied in various countries and regions due to its superior radiowave propagation characteristics. NICT has also contributed to the standardization of IEEE802.11af that defines specifications of WLAN systems in the TV band. Furthermore, NICT has developed box-type communication devices based on the IEEE802.11af standard and has been taking the lead to demonstrate the practicality of the TVWS communication technology.
On the other hand, the same convenience and simplicity as the traditional WiFi system are required for commercial deployment, and thus communication devices small in size and low in power consumption are strongly required as well as easy installation.
NICT has successfully developed a baseband IC based on the IEEE802.11af standard. By replacing the FPGA for baseband signal processing with the new IC, it becomes easier to prototype downsized communication devices with low power consumption. In addition, it becomes easy to implement the IC in/with other communication devices as a general component. Further cost reduction is also expected for contribution to the commercial deployment of the white-space WLAN technology.
Figure 1: The developed baseband IC and its mounting board. This baseband IC conforms to the IEEE802.11af standard that is the international standard of the WLAN system in the TV white-space spectrum.
Furthermore, NICT has successfully prototyped card-type communication devices small in size and low in power consumption at low cost. The card-type device meets the BPSK and QPSK specifications of IEEE802.11af, enabling a maximum communication speed of about 2.6 Mbits/s by using two units of the device. Other main features of this prototype are as follows:
- By installing the baseband IC, downsizing to 1/40, weight reduction to 1/30 and power-saving to 1/15 are achieved in comparison with previously developed box-type devices. The prototyping expense is also reduced to less than 1/10.
- The transmission signal waveforms of the device meet legal TV white-space regulations in foreign countries, including the United Kingdom (Up to 100mW is available) and the United States (Up to 50mw is available).
- This device has a USB interface as is the case with the common card-type communication devices, and can be operated by USB power.
- Available in a simple, all-in-one package including an antenna.
- This device can be operated in both access point and station modes. By using multiple devices, it is easy to deploy a network of white-space WLAN systems.
Figure 2: The developed card-type communication device in which the baseband IC is implemented. All the devices and components such as the baseband IC, an RF IC and an antenna are assembled in all-in-one package to reduce the device size.
Table 1: Specifications of the card-type communication device in comparison with the box-type communication device that was previously developed in NICT. By replacing the FPGA for baseband signal processing with the new IC, downsizing to 1/40, weight reduction to 1/30 and power-saving to 1/15 have been achieved. This prototype meets the BPSK and QPSK specifications of IEEE802.11af, enabling a maximum communication speed of about 2.6 Mbps by using two units of the device.
These features enable easy installation in any location here user traffic is congested for effective load-balancing. In addition, superior propagation characteristics of the TV band have the potential to establish communication infrastructure in some regions with difficulties in the deployment of wired networks and to reduce the number of devices in comparison with conventional wireless networks.
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