After a timeout period where no data is sent or received, the device is transitioned back to the idle state. When the radio is in the connected state, it requires a large amount of power. To use this power more efficiently, there are multiple possible sub-states a device can be in. If a device is receiving or transmitting data, it will be in the continuous reception state.
After it has been idle for a period of time, it is transitioned into a short DRX state. In this state, the network connection is still maintained but there are no specific radio resources assigned. If there is more data to receive or transmit, the RRC must allocate radio resources again for the device by sending control messages to the device and changing the state back to continuous reception. The long DRX state is identical to the short DRX state, except for that fact that it sleeps for a longer period of time before waking up to listen to control broadcasts.
The long DRX state is triggered after the radio has been idle for a configurably long period of time. If the device remains in the long DRX state for a period of time, it transitions back to the idle state. An important consequence of the timeout-driven radio state transitions, regardless of the generation or the underlying standard, is that it is very easy to construct network access patterns that can yield both poor user experience for interactive traffic and poor battery performance.
In fact, all you have to do is wait long enough for the radio to transition to a lower-power state, and then trigger a network access to force an RRC transition! The RRC is the key component connecting a device to the cellular network, but how does data flow into and out of the network? To understand this, we need to look at the end-to-end carrier architecture. In broad strokes, the network architecture is divided into three parts, as in the following figure from High Performance Browser Networking :.
To get a sense of how each of these architectural components work, the next few paragraphs will dive a little bit deeper into each. These base stations are responsible for maintaining the Radio Resource Controller state, and they perform all radio resource assignments for each active device in its broadcast area, called a cell. The eNodeB connected to a device controls all low-level operation of the device, such as handing the device over to a neighbouring base station as a user moves around in the physical world.
The eNodeB also sends and receives all radio transmissions to the devices it is responsible for using the LTE modem interface on each device. It performs traditional IP-switched data routing, and manages any network policies or accounting desired by the network operators. A major innovation of the UMTS network was that the higher data rate made it possible to transmit music files.
This makes the LTE network much faster, enabling the transmission of video and even streaming. UMTS was unable to deliver on its lofty promises, however.
In , Deutsche Telekom launched the iPhone on the German market in an exclusive deal, marking the start of a one-of-a-kind success story.
Another advantage of LTE: when building out the network, the mobile base stations that had already been built for GSM and UMTS could be used — making it unnecessary to establish an entirely new infrastructure for the fourth-generation network. LTE is available both in cities and rural areas. The buildout of the fourth generation of mobile communication technology will continue in the coming years.
Network operators have published many maps on the Internet showing their respective LTE coverage. On www. Locations on building roofs or existing towers are used for LTE antennas. An antenna on a roof is usually not more than ten meters in height. The supports are usually made of concrete, while steel lattice masts are also used. The antennas are affixed to the antenna masts and are connected to a radio head with an HF cable.
The other system technology is installed at the foot of the tower or in an equipment room. Think of it as taking the speedbumps off the roads in your city so you can zoom around faster. The major benefit to LTE is that in reduces the latency in data transfer. Both are a method of coding information for travel across airwaves. Like LTE, it moves larger packets of information at a faster rate. In that respect, everyone is available to use it, and it is widely believed to be a worldwide standard at some point.
Frequencies and spectrums are what your device runs on. A true LTE phone will operate on a variety of frequencies. Across the globe, different countries operate on different frequencies. A higher frequency does not denote a better network, either, as a lower frequency is more useful in rural areas. The best way to understand this is to examine countries in Europe. LTE typically operates on a frequency spectrum of MHz to 2.
A lower spectrum like the MHz will carry a signal over a larger area, thus reaching a larger number of people with less infrastructure change the carrier has to make. Something higher like the 2. Internationally, the ITU governs all spectrum for any type of communication. There are really huge, boring charts that explain it all.. First, the definitions. Frequency is a specific channel, like a radio dial. A radio station operates on a particular frequency, like A spectrum is a large block of bands, but also references the entirety of available frequency.
If the MHz spectrum is from , a band would be from Bands can be any size within a spectrum. So largest to smallest: spectrum, bands, frequency. All spectrum sales operate as an auction to maximize profit. When the ITU decides to auction off spectrum, they release a chunk like the MHz we discussed earlier. If that goes all the way from MHz, a carriers best chance for a better network is to own more bands or bandwidth in that spectrum.
If you want a big, fat network, you gotta have a bigger piece of the pie. Many mergers between carriers have to do with spectrum.
0コメント