What is 4G LTE-Advanced?
LTE-Advanced is the next level mobile broadband LTE technology. It is the faster version of the already fast wideband 4G. Some major networks in the UK and in the United States prominently, Sprint and T-mobile which are currently operating in the United States have already upgraded to LTE-Advanced. Wireless specialists have declared LTE-Advanced “True 4G” because it meets the specifications set by International Telecommunication Union’s (ITU) for 4G wireless systems. The goal is to provide a communication system which not only provides faster data speeds but also supports many more devices online at the same time with reduced latency. In order to meet the goal, the network providers are continuing to evolve the current LTE standard that is leading towards the 5G standards, which is known as LTE-Advanced Pro. As a result, we will get higher network capacity, more consistent connection,and cheaper data rates. A timeline for the progress in LTE standards towards 5G is shown in Figure 1 below.
Figure 1: Timeline for advancement in LTE-Advanced towards 5G.
How fast is LTE-Advance?
The main objective of LTE-Advanced is to add the IMT-Advanced functionality while maintaining the compatibility with LTE user equipment. It is important because if not enabled, the early adopters would be penalized when the carrier is upgraded to LTE-Advanced on the infrastructure side. LTE-Advanced is designed to provide the data rate up to 300 Mbps for downloading and 75 Mbps for uploads. Moreover, LTE-Advanced includes some new transmission protocols and multiple-antenna schemes (MIMO) which enable smoother handoffs between cells and increase throughput at cell edges. A graphical illustration of data rates of different releases of is shown in figure 2 below.
Figure 2: A Bar graph showing the comparison of data rates among different versions of LTE.
What LTE-Advanced adds to LTE?
LTE-Advanced is a speedy network. Theoretical peak download speeds are up to 300 Mbps while the standard data rate of 4G LTE is 150 Mbps. Other factors such as the type of device, proximity to a 4G mast and number of user on the network have a drastic affect on the network speed.
Moreover, LTE networks mainly use frequency reuse factor of one to maximize utilization of the assigned bandwidth. LTE uses the heterogeneous networks where the cells are of different size referred to as Macro, Micro, Pico and Femtocells. The actual cell size depends not only on eNB power but also on antenna position, as well as the environment of the location such as rural or urban, indoor or outdoor. An illustration of a heterogeneous network is shown in the figure below.
Figure 3: An illustration of a heterogeneous network with large and small cells.
In LTE-Advance, the technology of heterogeneous network is amalgamated with Carrier Aggregation, one of the big enablers behind faster data speeds. Carrier Aggregation enables the mobile device to receive several 4G signals of different frequencies all at once. For example, with LTE-Advance, we can receive an 1800 MHz and 80 MHz signal at the same time. Five component carriers, each having a bandwidth up to 20 MHz are combined to fom a data pipe of up to 100 MHz of bandwidth. But in LTE-Advanced Pro release the number of component carriers will increase to 32 different carriers.
Figure 4: Illustration of Carrier Aggregation in LTE-Advanced network.
Besides Carrier Aggregation, another feature which distinguishes LTE advanced from its predecessors is Multiple Input, Multiple Output (MIMO). MIMO allows base stations and user equipment to send and receive data using multiple antennas. It serves two purposes.
- In noisy radio environment, the multiple transmitters and receivers function together to focus the radio signals in a single direction. This beam forming feature amplifies the strength of received signal without increasing the transmission power.
- It is also used to increase data rates and the number of users for a limited spectrum. Currently, LTE supports MIMO, but only for downlink. It allows four transmitters in the base stations and four receivers in the handset. While in LTE-Advanced, up to eight antennas are used for downlink and up to four pairs for uplink.
LTE-Advance User Equipment Categories
In order to utilize the services of LTE-Advanced, you might need to get a new phone because, the standard 4G phones are not compatible with LTE-Advance. Many newly introduced mobile phones such as Samsung Galaxy S6, iPhone 6s, HTC One M9, Sony Xperia Z5, LG G4 and Microsoft Lumia 950 support it. Hence, over time, smarter phones will be introduced with LTE-Advanced support and as it becomes more widespread it should start filtering down to low-end devices too.
Towards next-generation Cellular Networks
Telecommunication is a fast evolving industry. The term 5G is abbreviated as Fifth Generation of mobile wireless systems. It is expected to be a big step as it promises to give high data rates along with IoT and other cutting-edge services. The specifications are still under development and it is expected to be deployed by 2020. The main goal of 5G is to receive data speeds up to 1 Gbps, which is a mind blogging number.
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