In Section 3, low-complexity solution methods for ES optimization model is analyzed, which includes time domain division method, local BS pair cooperation method, dynamic trigger and recovery algorithms for BMD sub-problem, and distributed heuristic algorithm for UAO sub-problem.
To constrcut ES optimization model in LTE networks, we discuss the system model firstly, which includes resource allocation scheme and power model of BS.
The Signal to Interference plus Noise Ratio (SINR) experienced by user i from BS j is given by
Further, require Resource Block (RB) of user i from BS j is given by
And load factor is considered as an important effect factor for dynamic part of BS power.
For BS j, assuming its maximum operating power when fully utilized is [P.
When a handover message is exchanged, mutual authentication based on an established security association should be performed between a sender and a receiver to defend against Man-In-The Middle or rogue BS attacks.
Through a Context Retrieval procedure, an authorization key AK to be shared with an MS is distributed to a target BS.
However, the Mobile WiMAX standard  allows a MS to perform an uncontrolled (unprepared) handover, which occurs when the MS tries to re-enter a target BS that did not participate in the normal Handover Preparation and Action phase.
Suppose [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] is the target BS of an MS handover at the i-th handover, where [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] is an initial serving BS.
If a BS is compromised, namely its neighbor cache is exposed to an attacker, then the communication link between the MS and the compromised BS can be eavesdropped.
On the other hand, another threat resulting from the compromised BS is to redirect all the MS traffic to the compromised BS.