Data transmission in mobile
I have recently started learning about the data communications and networking and along with that I am studying about the data transmission in mobile. I have got good notes on DCN but I am not able to collect some proper basic concepts of data transmission. So thought that possibly you members must be knowing something about it. (Please don't tell me to search on Google, because after searching there I found that the notes were made for professionals and not for newbie.) I am hoping some replies from your side soon as possible.
Re: Data transmission in mobile
The mobile networks are generally not available for data transmission. The transfer rates are too low, as the transmission technology and the modulation scheme on the transfer of language is designed. GSM does provide a method for a circuit-switched data transmission, however this is not particularly fast. To improve data transmission over GSM various methods have been introduced. For example, the X.75 link protocol to speed up the connection process. It is already known as an ISDN connection protocol. Furthermore, the digital data format V.110, but this was implemented only slowly from the system operators. In the GSM standard was with V.42bis data compression only for the air interface between mobile phone (MS) and base station (BTS) was introduced. All these methods were well-intentioned, but brought only one-off improvements. The basic disadvantages of the language were designed to transfer does not result in balance. :no:
Re: Data transmission in mobile
The consequent development of mobile data transmission is UMTS with HSDPA and HSUPA. In the future, follow LTE.
The first two methods for transmitting data in a GSM network is CSD (Circuit Switched Data), a circuit-switched data transmission method and SMS (Short Message Service) to the packet-switched connectionless message service, limited to 160 characters per message. CSD has already offered at the beginning of GSM. The data rate was a maximum of 9.6 kbit / s.. In the GSM Phase 2 have been kBit the speed of data transmission to 14.4 / s and sacrifice the error correction of the data. This decreased the quality of the connection.
Re: Data transmission in mobile
I would like to discuss something about the UMTS. UMTS was first introduced a mobile radio standard that allows basic language also find fast data transfers. A gross data rate of 384 kbit / s allows a net data rate of 360 kbit / s or 45 kB / s. About 10% of the bandwidth of UMTS will be lost for the overhead. UMTS is very slow compared to DSL. When establishing a connection, it takes a long time. If then flow time data, it is rather fast. The downloads go smoothly rather quickly. The best way to feel UMTS, Vodafone. Vodafone uses smaller data packets. Smaller packets have a higher priority in transmission. For the transmission of larger blocks of data takes a little longer. Another reason for the delay is the ramp-up time. The UMTS user is indeed always connected to the network. If, however, just no data is transferred, decreases its priority. If traffic is triggered again, it takes two to three seconds, until the data arrive at the receiver (latency). For Vodafone, the ramp-up time is between 800 ms to 850. Under optimum conditions are achieved with UMTS latency of 100 ms. In practice, 130-150 ms. In sporadic access and low data flow are only 250 to 300 ms.
Re: Data transmission in mobile
The latency time is the duration of a data packet from sender to receiver. Depending on your wireless network, transmission method, device and location can vary the latency. Applications that function expect a short latency in the mobile phone might not work. Who's a data plan from T-Mobile, Vodafone, E-Plus online, which will have perhaps noticed, that the images in the browser look pixelated or slushy. The retrieved Web pages are sent by those mobile operators through a proxy, the JPG and GIF files are compressed separately. One hand, this traffic will be reduced, thereby saving money. On the other hand, in one case or another the representation may be very bad. Would like to get at T-Mobile, you can turn off the proxy by selecting the first call on the website whether compressed or uncompressed the website.
