As Passive Optical Network（PON） is an important access scheme for next generation access networks

much attention ought to be paid to its energy efficiency

especially when energy shortage has become a serious problem in the world today.1 bit energy is an index for measuring energy efficiency.In PON P2MP networks

the increase or decrease of a single user’s 1 bit energy is not directly dependent on the changes of ONU assess bandwidth as it is also affected by the OLT broadcast effective factor α.Besides

device improvement will lead to bandwidth increase and the reduction of the total consumption of 1 bit energy will enable energy efficiency improvement.