you seems to be an engineer with out any knowledge. or may be a hora degree

4G is the cheapest method to give broadband....
read this
http://en.wikipedia.org/wiki/LTE_(Long_Term_Evolution)
Overview
LTE could allow data transfer rates to and from mobile devices between 15 and 100 times faster than 3G networks.
LTE provides downlink peak rates of at least 100Mbit/s, 50 Mbit/s
[1] in the uplink and RAN (Radio Access Network) round-trip times of less than 10 ms. LTE supports flexible carrier bandwidths, from 1.4 MHz up to 20 MHz as well as both
FDD (Frequency Division Duplexing) and
TDD (Time Division Duplex).
The goals for LTE include improving spectral efficiency, lowering costs, improving services, making use of new spectrum and reformed spectrum opportunities,
[1] and better integration with other open standards. The architecture that will result from this work is called EPS (Evolved Packet System) and comprises
E-UTRAN (Evolved
UTRAN) on the access side and
EPC (Evolved Packet Core) on the core side. EPC is also known as
SAE (System Architecture Evolution) and E-UTRAN is also known as LTE.
The main advantages with LTE are high throughput, low latency, plug and play, FDD and TDD in the same platform, improved end-user experience and simple architecture resulting in low operating expenditures. LTE will also support seamless passing to cell towers with older network technology such as
GSM,
cdmaOne,
W-CDMA (UMTS), and
CDMA2000.
[1]