Main requirements of LTE are:

• high spectral efficiency
• high peak data rates
• short round trip time
• flexibility in frequency and bandwidth

eNB or Evolved Node B is a network hardware in LTE that communicates with UE or mobiles. It contains Transmitter, Receiver and Control section.
Node B is the counterpart of eNB in UTRA of UMTS, where seperate Radio network controller(RNC) is present. The presence of integrated controller in eNB helps in reducing latency and response time