Wide band vs Narrow band communication
The scope of this question is too broad and cannot be answered well but I will try to give you some hints where to look for next:

Wideband communication

Wideband communication uses - as the name states - a wider portion of the spectrum. This has some advantages and disadvantages:


Wideband communication allows for a higher bandwidth and therefore for a faster communication
Wideband communication allows for spreading the signal to encrypt it (See: Direct Sequence Spread Spectrum and its derivates)
wideband communication allows for notching out narrow noise sources in the spectrum (See OFDM)
Wideband communication puts high demands on the linearity of filters (also the respective filter bandwidths are higher)
It's harder to send and detect wideband signals (You need a high Signal to Noise ratio) as the energy of the signal is distributed across the width of the spectrum which makes the signal weaker the wider it gets (transmitting on a given power level)
Wideband communication is almost exclusively done in higher frequencies (I'd say 433MHz+) as it's easier to design integrated circuits which have wider filters
Common modulation techniques are OFDM, GMSK, N-PSK and QAM-N in combination with frequency hopping
Examples of wideband communication are wireless networks: Wifi, LTE, HSPA


Narrowband communication

Narrowband communication uses a narrow bandwidth.


Narrowband signals are used in a slower form of communication where mainly voice or slow datastreams have to be transmitted
Narrowband signals usually have a far greater range of reception as narrower filters can be used and therefore cancel out unwanted wideband noise. The transmitted energy also concentrates on a smaller portion of the spectrum.
Common uses are FM radio, AM radio, satellite downlinks, morse code (CW), GPS signals and NOAA weather transmissions.
Common modulation techniques are AM, FM, SSB, BPSK and CW


Often IC manufacturers do focus on narrowband communication because often you need to flip a switch and propagate the change in signal through the air which does not need a high bandwidth. If you however try to send a x264 packed HD picture with 24MBit over the air you most certainly need a high bandwidth to transmit it in realtime. But according to the frequency usage plans you need to use a higher frequency band to be allowed to use a certain bandwidth (or power level). This is why wideband communication is almost exclusive to hardware used for 1 GHz+ operation.