We have seen all these terms, 4G, LTE, and WiMAX, floating around.  Then, we hear that ITU has not yet “accepted” any technology as 4G.   

We will try to define, as clearly as we can, the relationship between 4G and LTE.  First and foremost, ITU has a submission deadline of October 2009 for a 4G technology proposal.   3GPP will submit a proposal, tentatively referred to as “LTE-Advanced”, to ITU.  ITU does not use the term 4G; it refers to such technologies as “IMT-Advanced” (now, you know why the name “LTE-Advanced”!).  From the performance perspective, IMT-Advanced aims for the peak data rates of 100 Mbps and 1 Gbps for high-speed mobility and fixed/low- mobility, respectively. 

LTE-Advanced will meet such requirements and hopes to achieve peak spectral efficiency of 30 bps/Hz for the downlink and 15 bps/Hz for the uplink.  Up to (8x8) downlink MIMO and up to (4x4) UL MIMO are being considered.  The control-plane latency that will include a transition from an Idle to Active state would be less than 50 ms and the DRX (Discontinuous Reception) to Active state transition would take less than 10 ms. 

To meet IMT-Advanced requirements, LTE-Advanced will  support the frequency range 400 MHz to 5 GHz.  Current LTE specifications defined in Release 8 support peak data rates of 300 Mbps in the downlink and 75 Mbps in the uplink for the following parameters: 20 MHz spectrum bandwidth in both downlink and uplink, the modulation scheme of 64-QAM, (4x4) MIMO in the downlink, and one antenna transmission in the uplink.  Now that you know exactly what is going on regarding 4G and LTE, periodically keep checking this web-site. We will keep you updated!!