Differences Between 5G, 4G, 3G
5G? No one can yet say what 5G will be, let's not think so far. What does the so-called G of 2G/3G/4G mean and what are the essential differences? In fact, for users, the most important thing is to improve the speed and reduce the delay. Other user experiences are derived from these two main experiences.
Transformation of the transmission network. From SDH to MSTP (also based on SDH) to IPRAN, it can be said that the transformation of the transmission network is inseparable from the smooth application of 3G and 4G.
Miniaturization of base stations. The original 2G base stations are all cabinet-type, a large cabinet, baseband, radio frequency and other components are included in it, the equipment is bulky (up to 100-200kg), and it is inconvenient to transport. Deploying 7/8 feeders and then transferring 1/2 feeders is troublesome for wiring construction, and the overall construction period is relatively long. Later, in the 3G era, with the introduction of distributed base stations, the baseband and radio frequency units were separated. The RF unit is installed close to the antenna and only needs 1/2 feeder. The baseband and the radio frequency unit are connected by a field optical cable, which is convenient for wiring. At the same time, the baseband and RF unit are miniaturized (the total weight of the baseband + RF unit will not exceed 75kg), which can be carried and installed by a single person. A construction team of 2-3 people can complete the installation of 1-2 sites in one day. Moreover, the distributed base station is easy to install, and the baseband unit is small and flexible. It can be installed on the gantry, outdoor integrated power supply cabinet, and wall-mounted frame. The RF unit is waterproof and can be installed indoors and outdoors. It is suitable for many scenarios. The cabinet-type base station is not waterproof and requires equipment room conditions to be installed. Indoor macro base station BTS3012 (cabinet type) DBS3900 Distributed base station (distributed) Comparison between HUAWEI's rack-type macro base station and distributed base station. RBS 6201 - Ericsson (rack-mounted) RBS6601 - Ericsson+RBS Modules - Ericsson (distributed) Ericsson's rack-mounted macro base station and distributed base station comparison. Later, with the popularity of distributed base stations, various manufacturers also launched 2G distributed base stations, but 2G still accounts for a large proportion of cabinet-type base stations. Therefore, the distributed base station is not a strict distinction between 2G and 3G/4G. It just means that with the development of technology, with this kind of base station equipment, the network construction speed of operators has been greatly accelerated, allowing us to enjoy more advanced mobile communication technology in a shorter time.
The difference in the number of cell phone signals. For a long time, the standard for judging mobile phone signals is to look at the number of signal cells displayed on the mobile phone. Professionally speaking, it is the power of the base station broadcast/pilot/traffic channel received by the mobile phone. In the GSM era, this is actually quite effective, because GSM uses FDMA+TDMA, inter-frequency networking, and there is little or no co-channel interference, and it is more important to receive power. That is to say, the number of grids displayed by the mobile phone signal often determines the quality of the call and whether the call can be carried out smoothly. In the 3G/LTE era, the importance of received power, that is, the number of cell phone signals, has been relegated to the second place, because 3G/4G uses co-frequency networking and there is co-frequency interference, and CDMA/OFDM technology is used. Therefore, more attention should be paid to the interference level. In the case of an extremely low interference level, it does not matter if the received power is low. GSM is a TDMA system, and its received power is actually the power of a one-time slot, and the power of a one-time slot = the power of the entire carrier. However, the received power in 3G/LTE is not the full power of the entire carrier, but only a part of the power of the entire carrier. Therefore, it is unfair to compare directly, or it is difficult to compare directly.
Taking WCDMA as an example, Ec/No in the top window represents the interference level, and RSCP represents the received power. When the received power is as low as -100 dBm, it is estimated that there are only one or two signals left on the mobile phone. Since there is almost no interference from other co-frequency cells, the interference value is still at a "green" level. The SQI in the lower right window represents a voice quality, and 30 is already the best level. Even at such low received power, the quality and continuity of the call can be guaranteed smoothly due to the low level of interference. Therefore, those who have "signal obsessive-compulsive disorder" should modify their concept. Using 3G and LTE, they can't just judge heroes based on the number of cell phone signals.
