5G technical specifications
The wireless side refers to the wireless access network, which is composed of BSC, RNC, BTS, and NodeB.
BSC: base station controller
RNC: radio network controller
BTS: base transceiver station 4
NodeB: base station
MSC: mobile switching center
in the GSM system (2G) , The wireless part of the base station is composed of the wireless base station subsystem BSC and BTS
In the 3G system, the corresponding radio part, the radio network subsystem RNS, is mainly composed of RNC and NodeB. The
physical channel is the channel
for transmitting information. Physical channels generally refer to channels that rely on physical media to transmit information, such as telephone lines, optical fibers, coaxial, microwaves, etc.
Radio frequency (RF) means electromagnetic frequencies that can be radiated into space. The
frequency ranges from 300KHz to 300GHz. Radio frequency is radio frequency current, referred to as RF, which is an abbreviation of high-frequency alternating electromagnetic waves. The alternating current that changes less than 1000 times per second is called low-frequency current, and the alternating current that changes more than 10000 times is called high-frequency current, and radio frequency is such a high-frequency current. Radio frequency (300K 300G) is a higher frequency band with high frequency (greater than 10K).
The microwave frequency band (300M~300G) is the higher frequency band of radio frequency.
Three core levels of network architecture
Core layer: data notification forwarding;
router
Convergence layer: data communication across network segments; flow control
Layer 3 switches; routers
Access layer: Connect the computer to the local area network. The
second-tier switch; the hub
mobile communication network consists of three parts:
access network → mobile phone to base station,
bearer network → base station to computer room,
core network → computer room to backbone network. The
air interface is commonly called air interface, divided into Layer 3
Network layer
Data link layer
Physical layer
5G new wireless air interface commonly known as NR (New Radio)
5G wireless protocol stack
is responsible for processing the data of the wireless link between UE and gNB
UE: User Equipment
gNB: Provides NR (air interface) user plane and control plane protocol terminal nodes for UE and is managed by NG (radio access network and 5G core network) interface is connected to 5GC (5G core network)
AMF: access and mobility management functions,
radio resource management (RRM): it is a wireless user terminal in the network under the condition of limited bandwidth To provide service quality assurance, the basic starting point is to flexibly allocate and dynamically adjust the available resources of the wireless transmission part and the network under the conditions of uneven distribution of network traffic and fluctuations in channel characteristics due to channel weakness and interference, to maximize the increase The wireless spectrum utilization rate prevents network congestion and keeps the signaling load as small as possible.
NAS layer function
NAS: Mainly responsible for functions and processes that have nothing to do with access and are independent of wireless access
Network wiring and number system conversion
What is a signal :
information,
data,
signal
classification :
analog signal: continuous, the signal size fluctuates high and low, not a fixed value
Digital signal: discrete, the signal size is a fixed value
Distorted signal during transmission: noise attenuating
analog signals easily transferred
advantages of digital signal:
anti-interference ability
transmission distance and to ensure the quality of
the twisted pair
total of eight twisted pairs are twisted together twenty-two
common there are
five categories (Cate 5)
Category 5 (Cate5e)
. 6 class (Cate6)
UTP Category
shielded twisted pair:
copper overwrap layer of metal omentum
electromagnetic environment is very complex industrial environments
unshielded Twisted-pair cable:
used in environments where electromagnetic interference is relatively weak.
Twisted-pair cable standards and classifications
EIA/TIA-568-Commercial building telecommunication wiring standard
Cat 5 is
mainly used for 100Base-T and 10Base-T networks,
Cat 5e has lower
attenuation, Less crosstalk, better performance than Category 5 cable,
Cat 6
transmission rate up to 1Gbps, Cat 7 transmission frequency up to 10Gbps
UTP cable
TIA/EIA organization defines two different modes, called T568A and T568B
T568A line sequence white green green white orange blue White Blue Orange White Brown Brown
T568B Line Sequence White Orange Orange White Green Blue White Blue Green White Brown Brown
Two types of cables can be created using T568A and T568B wiring standards:
Straight cable:
It is the most common type of cable. If one end of the cable is T568A, then the other end is also T568A, if one end is T568B, then the other end is also a T568B
crossover cable:
both wiring modes will be used at the same time. One end of the cable is T568A, and the other end is T568B. Straight-through cables and crossover cables have their specific uses on the network. The type of cable required to connect two devices depends on the pair of wires the device uses to send and receive data
Two devices that are directly connected and use different pins for transmitting and receiving are called dissimilar devices
Other dissimilar devices that require a straight-through cable include:
switch port to router port;
hub port to PC;
switch port to PC.
Other similar devices that require a crossover cable include:
switch port to switch port;
switch port to hub port;
hub port to hub Port;
router port to router port;
PC to router port;
PC to PC
The ends of UTP and STP cables are usually RJ-45 crystal head
optical fiber characteristics
| Single mode fiber | Multimode fiber |
|---|---|
| For high speed, long distance | For low speed, short distance |
| Harder to terminate | Easier termination |
| Narrow core wire, laser source required | Wide core wire, good concentration, the light source can be laser or light-emitting diode |
| Minimal dissipation and high efficiency | High dissipation and low efficiency |
Optical fiber interface classification
FC round threaded optical fiber connector
ST snap-on circular optical fiber connector
SC square optical fiber connector
LC narrow body optical fiber connector
MT-RJ transceiver integrated square optical fiber connector
cable connection
Standard network cable
Crossover network cable
Full reverse line → Console
a wireless transmission medium
utilizing an electromagnetic wave transmission medium serving as a transmission medium
comprising: radio waves, microwaves, laser, infrared and
radio wave
electromagnetic radio frequency in free space (air and vacuum) propagating
propagation characteristic
the lower the frequency, the smaller propagation loss, coverage The farther the distance, the
higher the frequency, the greater the system capacity, and the closer the coverage distance.
Radio wave propagation mode
Ground wave,
sky wave,
straight line propagation
5G uses millimeter waves in microwave 30 to 300GHz, wavelength 10mm 1mm, straight line propagation
Ground wave: Radio wave propagating along the surface of the earth
Sky wave: Radio wave propagating by the reflection of the ionosphere in the atmosphere.
Straight line propagation: Microwaves can neither propagate in the form of ground waves (easy to be absorbed) nor rely on the reflection of the ionosphere. Propagating in the form of sky waves (penetrating), microwaves can only travel in straight lines like light. This kind of electromagnetic wave propagating in a straight line is called space wave or visual wave
Microwave includes:
decimeter wave, centimeter wave, millimeter wave.
Ground microwave:
point-to-point transmission distance 50-100KM.
Satellite microwave:
distance 36,000 km. Long transmission delay.
Infrared and laser.
Infrared:
not interfered by radio waves, close range transmission
by the large sun interference, can not pass through the wall
of the laser:
transmission distance, delay long
straight line, can not cross the barrier
of the antenna
means for radiating and receiving radio waves is called an antenna
generally by the transducer, the feed network, the three housing Part of the composition
Vibrator: has the function of guiding and amplifying electromagnetic waves, making the electromagnetic signal received by the antenna stronger. The
vibrator emits electromagnetic waves into space. The
feed network connects the transceiver and the antenna vibrator. The
outer cover is used to protect the internal components of the antenna.