If there are two masters on the same bus, there are arbitration procedures applied if both try to take control of the bus at the same time. When two chips try to start communication at the same time they may even generate a few cycles of the clock and data that ‘match’, but eventually one will output a ‘low’ when the other tries for a ‘high’. The ‘low’ wins, so the ‘loser’ device withdraws and waits until the bus is freed again. Once a master (e.g., microcontroller) has control, no other master can take control until the first master sends a stop condition and places the bus in an idle state.
due to significantly higher propagation loss. Therefore, the two
wireless bands provide widely different, yet complementary,
characteristics in terms of range and throughput. However, there is
a greater need for an efficient multi-band operation that enables
selecting the optimum interface based on the communicating
stations physical proximity and multi-band channel conditions. In
this paper, we present techniques that facilitate green multi-band
IEEE 802.11ad for portable devices. We performed a detailed
simulation study and the results indicate that the proposed
techniques reduce energy consumption of the multi-band Wi-Fi
devices as they are at least 40% more power efficient.