The easiest way to arrange aggregation is to use contiguous component carriers within the same operating frequency band as defined for LTE , so called intra-band contiguous. This might not always be possible, due to frequency allocation scenarios.
For non-contiguous allocation it could either be intra-band, i. When carrier aggregation is used there is a number of serving cells, one for each component carrier. The coverage of the serving cells may differ — due to e. In the inter-band CA example shown in figure 3, carrier aggregation on all three component carriers is only possible for the black UE, the white UE is not within the coverage area of the red component carrier. MIMO is used to increase the overall bitrate through transmission of two or more different data streams on two or more different antennas - using the same resources in both frequency and time, separated only through use of different reference signals - to be received by two or more antennas, see figure 4.
One or two transport blocks are transmitted per TTI. To be able to adjust the type of multi-antenna transmission scheme, according to e. The different transmission modes differ in;.
Naturally it is also required that the UE support this. In R10 three new UE categories are introduced, category 6, 7 and 8 — where UE category 8 supports the maximum number of CC and 8x8 spatial multiplexing.
In multi-antenna techniques precoding is used to map the modulation symbols onto the different antennas. The type of precoding depends on the multi-antenna technique used as well as on the number of layers and the number of antenna ports. The aim with precoding is to achieve the best possible data reception at the receiver. Note that the signal will be influenced by fading of various types, which can also be seen as some type of coding caused by the radio channel. To handle this, known reference signals will be transmitted together with the data, and used by the receiver for demodulation of the received signal.
Using this together with knowledge about the used code-book based precoding, the UE can demodulate the received signal and regenerate the information sent. Knowledge about the reference signal will provide information about the combined influence of radio channel and precoding, no pre-knowledge about the precoder is required by the receiver, this case is referred to as non-codebook based precoding, see figure 6.
In LTE-Advanced, the possibility for efficient heterogeneous network planning — i. Having more users on wireless networks means that the infrastructure needs to advance to accommodate them all. No commercial wireless network can deliver that yet. The standard also covers a bunch of other technical stuff: True LTE has to be based on a fully Internet Protocol packet-switched network, and it needs to have scalable channel bandwidth, specific Quality of Service goals, spectral efficiency targets, and the like.
The LTE we use today offers some of those things, but not all of them. Today, a mobile user in North America on a 4G LTE network can expect top download speeds of 13 mbps around large-population areas, as we discovered in our recent barrage of cross-continental network tests.
Besides, the mbps minimum requirement is sort of a best-case scenario in the lab. Real-world LTE-A speeds are more likely to be in the range of 30 to 40 mbps on average. It promises to deliver download speeds of up to 3 gbps for fixed wireless installations. And it packs more speed into the same amount of spectrum, which should allow more people to access the network at once. LTE-A incorporates of a number of techniques and technologies hardware and software that work in concert to meet higher network-performance standards.
This simplified, flatter version of the network architecture mean response times are much quicker and therefore users of the network would realise much better data rates. The main aim for LTE-A Pro is to increase the data speeds and bandwidth that are currently available for mobile communications. User experience will be significantly improved as a result optimising the capacity, performance and functionality of existing LTE-A networks.
Latency will also decrease, allowing for much quicker response times; vital for the development of IoT internet of things technology. It will lessen to just 2ms compared with 10ms at LTE-A. There will be a number of different technologies that will be incorporated into LTE-A Pro, many of which will be advanced and evolved versions of the things that are already present in the existing LTE-A and LTE networks.
Data speeds will be increased by using and improved version of Carrier Aggregation technology, the process in which larger amounts of bandwidth is made available by using more than one carrier. It is already used in LTE-A, but with LTE-A Pro the number of different carriers that will be able to simultaneously supported will increase from just five, all the way up to A huge advanced again for IoT devices that rely on constant connectivity, often when moving.
Greater demand for data transfer means that small cells are being deployed within range of macro cell coverage to provide dual connectivity which significantly improves per-user throughput and mobility robustness, again this is an area which will be continued to be improved upon with LTE-A Pro.
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