Cellular Network

The mobile phone service difference is divided into one of hexagon branch area, every village set a base station. Formed shape looks like honeycomb structure, thus the mobile communication mode is called cellular mobile communication mode. Cellular network and may be classified as analog cellular networks and digital cellular network, the main difference in the transmission of information way.

Practical reasons

Cellular networks to be used extensively reason is originates from a mathematic hypothesis, hexagon considered use at least a nodes may cover the largest area of graphics, for saving equipment construction cost consideration, hexagon is best choice. This forms of network covering together, shape is very much like a honeycomb, so called cellular networks.

part

Cellular network composition has three main parts: mobile station, base station subsystems, network subsystem. Mobile station is our network terminal equipment, such as cell phones or some cellular industrial equipment. Stations including our daily see subsystem mobile base station (tower), wireless transceiver large equipment, special network (typically fibers), countless digital equipment etc. We can put the base station subsystem is seen as the wireless network with wired network between converters.

Common cellular network type toinclude: GSM network (some countries called PCS -- 1900), CDMA network, 3G network, FDMA, TDMA, PDC, TACS, AMPS, etc

Cellular and frequency reuse

Honeycomb: a large area is divided into several small honeycomb, using multiple small power transmitters instead of a high-power cellular networks

The transmitter. Commonly used to describe the hexagon honeycomb shape.

Frequency multiplexing: each honeycomb use a set of channel. If two honeycomb apart, can use far enough in the same group channel. Clusters (cluster) : of N cellular composition of cellular group, use all frequency resource frequency multiplexing factor (reusefactor) : 1 / N for of hexagon honeycomb, N = i2 + I * j + j2 = 1, I > > = 1, j, therefore, N = 3,4,7,9,12...

Cellular geometric said

Cellular usually use hexagon prond. Why is hexagonal rather than round? The vertices to geometric center isometric polygon, can complete (without overlap) in land cover an area of geometric shapes are: may square, equilateral triangle and hexagonal three kinds of shapes. In the square, equilateral triangle and hexagonal, area of hexagon is the largest.

Cellular coordinate system

Use (I, j) says a honeycomb coordinates. For example: cellular A coordinate for (2, 1)

Honeycomb channel allocation

FDMA system: by signal attenuation principle. Key: treat spectrum is divided into several channel (user channel carrier), far enough in distance can multiplexing channel = > channel planning affect system performance.

Static and dynamic channel allocation: - static channel allocation: each honeycomb preassigned a fixed set of channel, implementation is simple.

Dynamic channel allocation: stations from MSC in dynamic allocation a channel (percall), honeycomb can use all of the channel and reduce the blocking probability, realize complex, requiring a real-time flow testing and base station coordination between processing.

Network type

Common cellular network type toinclude: GSM network (some countries called PCS -- 1900), CDMA network, 3G network, FDMA, TDMA, PDC, TACS, AMPS, etc.

Type classification

Distributed cellular networks

A distributed cellular network (100) provides with multiple mobile station (102) of the wireless communication. Multiple base transceiver letter machine network components (104) is configured to in a wireless medium with multiple mobile communication platform (102), each of them receiving letters Taiwan includes base for coupled to a network (110) network interface. At least one mobile station controller network components (108) includes a suitable for coupled to the network (100) network interface. On the system (100), so to efficiency and configuration for base transceiver letter (sets), base station controller (104 106) and mobile switching center (108) the communication between the portfolio for load balancing. The invention of the advantages including low cost transceiver letter machine (104) combined with flexible deployment, thus with low cost for large area realized the telecommunication covers.

A distributed cellular communication systems, including a network; A coupled to the network public switched telephone network (PSTN), Multiple coupled to the network, receive letter machine, multiple transceiver letter machine geographically separated, and each one is configured in a wireless medium and related district of mobile communication stations, At least one coupled to the network data processing system, this at least a data processing system is configured to execute a computer program, this computer programs include suitable for enables multiple transceiver letter function in the mobile station and between a mobile platform and PSTN to transfer data between the software function block, these software function blocks including: an implementation MM function of mobility management (MM) function blocks, An implementation VLR function of visitor location registration (VLR) function blocks, An implementation CM function of communication management (CM) function blocks, Multiple implementation RR function radio resources (RR) function blocks, wherein RR features included in the mobile station from one village to another village move when switching multiple transceiver letter machine, so as to keep the communication between the moving platform and network communication between.

Cellular mobile phone

So-called cellular mobile phone "shall refer to a mobile phone services region can be divided into several each other adjacent area, every village set a base station network structure. Since each district positively hexagon, another adjacency, look from whole, shape resembling a honeycomb, so people call it "honeycomb" nets. With several honeycomb district covers the whole service of large, medium capacity mobile phone system is called cellular mobile phone system, the abbreviation cellular mobile phone.

Cellular mobile phone biggest advantage is frequency can be reused. Perhaps everyone know, in our that mobile phones mobile communication, everyone takes a channel, i.e., the system will take out a channel for you. Meanwhile call it, limited channel may not use, so they will appear communication obstruction of the phenomenon. Using honeycomb structure can use the same group of frequency in several distance apart of village repeated use, so as to achieve the purpose of saving frequency resource. For example, we will be a city divided into 72 village, every 12 village form a community group. Let them use jointly 300 channel. So, we can put 300 channel is divided into 12 group channel, each group 25 channel, the first community group use group 1 channel, the second district of use in group 2 channel, and so on. After appropriate arrangement, different area of the same Numbers of residential district is group channel can be reused. Although these cells sites by use of radio frequency and same, but because they are far apart to each other, and waves scope is limited, each other can't cause interference. So, a group of frequency reusable 6 times, originally 300 channel can only for 300 users at the same time, but now I can also calls for 1,800 users to talk to each other.

Cellular mobile phone system mainly consists of the mobile station (auto telephone, mobile phone, etc.), wireless stations and mobile telephone exchange center. Every village stations are connected with mobile phone exchange center, forming a cellular mobile networks. Mobile-phone networks with city PSTN and domestic and international long-distance telephone network is linked together, make the mobile phone users can not only with net of mobile phone users on the phone, still can with larger range of mobile users and fixed users on the telephone.