So after looking at the first three generations, here we are. I do not want to call LTE as a 4G standard yet as according to International Telecommunications Union-Radio communications sector (ITU-R) for any 4G system, enhanced peak data rates to support advanced services and applications (100 Mbit/s for high and 1 Gbit/s for low mobility )..Now thats something really huge..From 10s of Mbps we are going to 1Gbps!! I am not quite sure if any of the service provider actually provides these data rates. Well it is advertised as 4G though..There were couple of other standards beyond the third generation such as HSPA+ and WiMAX. So the operators had to choose between these three. For now we will be focusing only on LTE, the Long Term Evolution. I really like the name given to this standard, it actually suggests that atleast this generation will be able to cater our needs for a longer time. As we have seen in the previous posts, the wireless communication industry has seen rapid growth over the years. The forecasts say that 3GPP LTE will enable the growth of cellular systems and might be able to meet the need till 2017. Now thats a long time considering the growth patterns seen in last 5 years. The number of connected devices will reach 15 billions by 2015!! So we will need robust systems to support these big number of users and speed and coverage will be the decisive factors in competitors..
It is said that "Necessity id the mother of inventions"..Well same goes for the development of LTE. There were some important driving factors in the development of LTE.
1. Ever increasing demand of higher data rates.
2. Increasing number of connected devices
3. Flexibility for the operators (LTE supports flexible bandwidths)
4. Availability of smart phones
There are several requirements for LTE published by ITU. (I am using the official ITU document for reference)
1. Peak data rate : 100 Mbps DL/ 50 Mbps UL within 20 MHz bandwidth
(DL : 5bps/Hz, UL : 2.5bps/Hz, 2x2 MIMO default)
2. Co-existance with 2G and 3G systems.
3. Latency : upto 100ms
3. Mobility : Optimized for 0 ~ 15 km/h, 15 ~ 120 km/h supported with high performance.Can support upto 350km/h.
4. Spectrum usage:Flexible.Permissible channel bandwidths:1.4, 3, 5,10, 20 MHz
5. Supported duplexing : FDD, TDD
It is said that "Necessity id the mother of inventions"..Well same goes for the development of LTE. There were some important driving factors in the development of LTE.
1. Ever increasing demand of higher data rates.
2. Increasing number of connected devices
3. Flexibility for the operators (LTE supports flexible bandwidths)
4. Availability of smart phones
There are several requirements for LTE published by ITU. (I am using the official ITU document for reference)
1. Peak data rate : 100 Mbps DL/ 50 Mbps UL within 20 MHz bandwidth
(DL : 5bps/Hz, UL : 2.5bps/Hz, 2x2 MIMO default)
2. Co-existance with 2G and 3G systems.
3. Latency : upto 100ms
3. Mobility : Optimized for 0 ~ 15 km/h, 15 ~ 120 km/h supported with high performance.Can support upto 350km/h.
4. Spectrum usage:Flexible.Permissible channel bandwidths:1.4, 3, 5,10, 20 MHz
5. Supported duplexing : FDD, TDD
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