What is the difference Between the 4G, 4G LTE, VoLTE, FD-LTE and TD-LTE networks?

LTE (Long Term evolution) is termed as 4th Generation Telecom Network.

Hence the terms 4G and LTE are used interchangeably.

VoLTE (Voice Over LTE network) is one of the feature of LTE to allow voice services. LTE is all IP based and there is no circuit switching like in 2G and 3G. To support voice call, VoLTE in introduced with IMS network support in the core.

FD-LTE (Frequency division duplex) and TD-LTE (Time division duplex) are two ways to implement LTE network.

In FD-LTE, as the name suggest, bandwidth is not shared between downlink and uplink i.e. both uplink and downlink resources have their own bandwidth.

In TD-LTE, bandwidth is shared between uplink and downlink periodically (there are several configuration supported in LTE which describes how downlink and uplink resources share bandwidth)

Both configs (FD-LTE & TD-LTE) have their pros and cons. With FD-LTE, you will get more throughput but spectrum cost will be more. With TD-LTE, in addition to less spectrum cost, power control mechanism will work more faster however throughput will be less with TD-LTE.

Choosing FD-LTE or TD-LTE for an operator also depends on many factors i.e. available spectrum, government regulations etc.