Table 1 Notations

\(q_{i}^{j}\)

Contact quality between vehicle v _i and v _j

TTL

Remaining time a data chunk can survive in the network

FCC

Forwarding communication capacity

P _rio (d _k )

Priority of a data chunk d _k

\(s_{d_{k}}\)

Size of data chunk d _k

c _i

Storage capacity of vehicle v _i

c _FTW

Length of selected contact duration in the dense case

X

Data chunk set X={d₁,d₂,d₃,⋯ }

Y

Candidate vehicle set Y={N₁,N₂,N₃,⋯ }

w(x,y)

Delivery utility for x∈X to execute y∈Y

Bipartite matching between x∈X and y∈Y where 1

m(x,y)

denotes an assignment, 0 denotes no assignment,

and “ −” indicates an initial or inexecutable status

L(v)

Labeling function of Hungarian algorithm [34], v∈X∪Y

L^′(v)

Previous record of L for any given v∈X∪Y

S

Data chunk set in the current consideration of allocation, ⊆X

Relay vehicles (⊆Y) that are reachable by data chunks ∈S,

N(S)

i.e., {j∣∃m(i,j)=0or1,j∈N(S),i∈S}

T

Set of vehicles that have been saturated (assigned)

\(E^{*}_{x}\)

An alternating tree starting from x