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Table 1 Symbols used in the access control and channel assignment algorithm

From: Deployment analysis and optimization of heterogeneous networks under the spectrum underlay strategy

Symbols

Meaning

SINR u

The SINR at each secondary link u

P u

The transmit power of secondary transmitter u

P k

The transmit power of secondary transmitter k

P v

The transmit power of primary transmitter v

lds(u)

The link distance of secondary link u

dss(k,u)

The distance from secondary transmitter k to secondary receiver u

dps(v,u)

The distance from primary transmitter v to secondary receiver u

k

The index of active secondary transmitters

Φ

The set of active secondary transmitters

γ

The path loss exponent (a value between 2 and 4)

Sl

The number of secondary links

SINR v

The SINR at each primary link v

ldp(v)

The link distance of primary link v

dps(k,v)

The distance from secondary transmitter k to primary receiver v

Pl

The number of primary links

c u

The data rate of the secondary link

c v

The data rate of the primary link

B

The primary channel bandwidth

α

The SINR threshold for the secondary network

β

The SINR threshold for the primary network

S

The swarm

X i

The position of the ith particle

V i

The velocity of the ith particle

V max

The maximum velocity

P i

The best position ever visited by the ith particle

X i

The candidate channel allocation vector of the ith particle

P i

The best channel allocation for secondary links find so far by the ith particle

g

The index of the best particle in the swarm

T max

The number of iterations

c 1 , c 2 , c 3

The cognitive, social and socio-cognitive factors

w, w 1

The inertia weights

PC

The number of primary channels to share

Spectrum status

The channel allocation vector for primary links

P g

The best particle in the swarm