Link adaptation in unlicensed radio bands

This paper presents a new collaborative mechanism for efficient coordination of radio communication devices, in particular addressing the unlicensed ISM band at 2.4 GHz. As the traffic in the ISM band is increasing tremendously, the potential for interference between uncoordinated devices is becoming a problem and can result in severe degradation of the performance of these systems. Devices using the same technology can benefit from standardized QoS solution, as for example introduced in WLAN IEEE Some recent 802.11e [1]. But the unlicensed ISM typically supports heterogeneous networks using different technologies. Collaborative and non-collaborative mechanisms that have been proposed are designed only for some particular systems and are inefficient because they result in a lack of a spectrum map. The collaborative mechanism proposed in this paper enables spectrum coordination between multiple wireless devices using conventional radio standards such as IEEE WLAN 802.11x, Bluetooth, ZigBee, and so on. The proposed mechanism permits flexibility in spectrum sharing procedures, which can take into account more complex parameters and results in a more efficient spectrum allocation. The collaborative mechanism is based on a Shared Broadcast Control Channel (SBCH). The SBCH is a low rate signal using continuous phase modulation. Simulation results show that the SBCH signal can be generated by conventional transmitters and can be detected with conventional receivers.