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Advances, Systems and Applications

Table 1 Summary of key notations

From: Joint task offloading and resource allocation in mobile edge computing with energy harvesting

Notation Description
I number of SMDs
\(\mathcal {I}\) set of SMDs
ci number of CPU-cycle required to accomplish task i
si input computation file size of task i
oi output computation result size of task i
\(t_{i}^{\text {max}}\) maximal delay requirement of task i
λi offloading ratio variable of task i
T total EH and task offloading time
α time switching factor
bi bandwidth between eNodeB and SMD i
hi uplink channel gain from SMD i to eNodeB
\(p_{i}^{u}\) uplink transmission power of SMD i to eNodeB
\(r_{i}^{u}\) uplink transmission rate of task i
\(t_{i}^{u}\) uplink transmission time of the partial task i
\(E_{i}^{u}\) uplink transmission energy consumption of partial task i
\(f_{i}^{\text {loc}}\) CPU-cycle frequency of SMD i allocated to the task
\(F_{i}^{\text {max}}\) maximal CPU-cycle frequency of SMD i
\(t_{i}^{\text {loc}}\) local computation time
\(E_{i}^{\text {loc}}\) local computation energy consumption of SMD i
\(\kappa _{i}^{\text {loc}}\) conversion coefficient of SMD i
\(F_{\text {mec}}^{\text {max}}\) maximal CPU-cycle frequency of MEC server
\(f_{i}^{\text {mec}}\) CPU-cycle frequency of MEC server allocated to the task i
\(t_{i}^{\text {mec}}\) MEC server computation time of task i
\(E_{i}^{\text {mec}}\) MEC server computation energy consumption of task i
κmec conversion coefficient of MEC server
\(p_{i}^{d}\) downlink transmission power of eNodeB to SMD i
\(r_{i}^{d}\) downlink transmission rate from eNodeB to SMD i
\(t_{i}^{d}\) downlink transmission time from eNodeB to SMD i
\(E_{i}^{d}\) downlink transmission energy consumption of eNodeB to SMD i
\(E_{i}^{\text {har}}\) total energy harvested by SMD i
ηi energy conversion efficiency