From: Multichannel MAC protocol with dynamic backoff contention for distributed cognitive radio networks
Symbol | Explanations |
---|---|
N | Number of SUs in the DCRN |
N st | Number of successful transmission pairs in a MAC cycle |
M | Total number of licensed data channels |
M ic | Number of idle licensed channels |
M sic | Number of remaining sensed idle licensed channels |
K | Largest number of slots for the contention phase |
w i | Average number of winning slots (successful SUs) in the ith backoff |
 | contention window |
W | Number of slots won in the whole contention phase |
Q | Parameter which is broadcasted on the update slot to indicate the |
 | number of contention slots of the next backoff window |
Q 1 | Number of contention slots in the first backoff window |
Q i | Number of contention slots in the ith (i>1) backoff window |
Q c | Number of contention slots in the whole contention phase |
P d | Each SU’s local detection probability |
P f | Each SU’s local false alarm probability |
P s | Probability of a successful RTS contention in the initial backoff window |
P T | Probability of a successful data transmission in a MAC cycle |
P NT | Probability of fail to transmit data in a MAC cycle |
D | Average channel access delay in terms of MAC cycles |
T cycle | Time duration of a MAC frame cycle |
T c | Time duration of contention phase |
T ct | Time duration of contention phase and transmission phase |
T tr | Time duration of data transmission phase |
α | Average utilization probability for all the licensed channels |
σ | Duration of a contention slot in contention phase |
R | Fixed rate for each data channel |
n 1 | Number of remaining SUs (which still need contention) in Algorithm 1 |
n 2 | Number of remaining contention slots in Algorithm 1 |