When a new call request of a FU arrives to a CFAP, the CFAP first performs a channel allocation scheme to allocate a channel to the FU.
After allocating a channel k to a new call request, CFAP sends a verification request to the FMS to verify if the QoSs of other MUs using the channel k are violated.
When a CFAP allocates a channel to a FU, it first has to provide the required QoS of the FU.
In the FAP-based cognitive channel allocation scheme (denoted as CFAP-based scheme), each CFAP will measure the interference level of all available channels which are not allocated to ongoing FUs of the CFAP.
is the total interference level of channel c is measured at the CFAP j.
A CFAP periodically updates interference data of all channels measured at its covering MBS.
When the CFAP receives a connection request of a FU, it will select the channel [k.
M] is the total interference level of channel c which is measured at the covering MBS M of the CFAP.
When performing simulation experiments, we realized that the CFAP-based scheme will locally assign a channel k which causes minimum interference to CFAPs i.
According to the updated data, a CFAP divides the channel pool into two sets [C.
When the CFAP j receives a new connection request of a FU, the "flexible scheme" operation is described in two steps as follows:
The femtocell coverage radius is 15m and CFAP has antenna height between 1m to 5m.