In my opinion, this is going to drive the new deployment strategy. LTE is purely a data aimed technology. Compared to earlier wireless technology 3G,GSM, cdma2000 which primarily was focused on providing voice.
Think of voice, which consumed the a good and reliable amount of wireless resource (time (GSM slots) or codes (cdma/wcdma long codes)) for short duration of time. While when one is talking about packet services. One does not want to "dial-up" a data session. Its an always on connectivity when you are connected to through a 4G-MOBILE terminal. The "dongle" based access is a different case.
Both dongle & mobile based access have different constraint in itself for the same radio-access technology.
Dongle are powered through the USB ports of the laptop or desktop kind of device, hence power may not be the primary concern. Size of the dongles are small than the mobile terminals and hence the capability of antenna placing in that form factor is challenging. Moreover, dongles will have a fixed (almost) orientation, may not able to completely exploit the polarization diversity. Mobile terminals (most would be next generation smart phones) though being larger are more likely to come with touch and hard-keyboards and hence is more likely to block the antennas with your palms (this would remind the iphone antenna problems). Smart phones with accelerometer and auto-rotating display allows one to hold the device in any direction. These things make it more challenging to design multiple antennas on the mobiles even if they are of large size compared to dongles.
In case of the mobile form-factor, one would always want be "connected" means no data-connection need to be established. For e.g. social networking, Instant messaging, email access through push-notifications, would require frequent connections, but not stringent requirements on "reliable/quality" as in voice sessions. The device being really "MOBILE" would keep search for better sector/cell and see time-varying channels, responds to network to the dynamic conditions of the channel. Also the new technology like WIMAX or LTE operate over a wide band (atleast 20MHz) which requires the wide-band operation higher-rate signal samples. Hence, more power and low battery time. If one deploy base-stations such that the entire area is provided almost good quality signals (that is a good SINR), each mobile terminal can ride on good channels and good instantaneous data rate. This will allow users to push and retrieve high-rate packets in a given burst.
This can be achieved by providing more overlapping ( note overlapping also introduces inter-cell interference) coverages, many base-stations. Many pico-cells, femtos (ofcourse small in cost too) would be required to satisfy a good quality data service experience, with efficiency of power consumption of the mobile (smart phones).
And a presentation from Alcatel Lucent is here
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