Microwave is a transmission method of communication. For digital microwave communication technology, microwave is used as a way to complete the transmission of digital information. At the same time, through the use of radio space, it is possible to transmit all kinds of irrelevant information. Up to now, digital microwave communication technology has become a widely used technology. The technology has many functions, such as completing the transmission of telephone signals, data signals and image signals.
Part 1. The development of Digital Microwave Communication Technology
Microwave communication technology has been in existence for more than half a century. It is a wireless communication method for information dissemination through the ground line-of-sight in the microwave frequency band.
The initial microwave communication systems were all analog systems, which, together with the coaxial cable carrier transmission system at that time, were an important transmission method for the long-distance transmission trunk line of the communication network.
With the continuous development of technology, in addition to the traditional transmission field, digital microwave Technology is also attracting more and more attention in the field of fixed broadband access. LMDS working in the 28GHz frequency band has been widely used in developed countries, indicating that digital microwave technology will still have a good market prospect.
Part 2. Analysis of Characteristics of Digital Microwave Communication Technology
Digital microwave communication technology has many characteristics, the specific performance is as follows:
2.1 Anti-interference.
Digital microwave communication technology has strong anti-interference ability, and there will be no accumulation of line noise. When the digital microwave acting as relay communication, the regeneration function of digital signal can prevent the line noise from accumulating station by station.
But if the digital signal has a bit error due to interference, it is very difficult to effectively solve the bit error problem in subsequent transmissions. Therefore, if it happens, the bit errors tend to accumulate station by station.
2.2 Confidentiality.
Digital signals are very easy to be encrypted, and digital microwave communication equipment has the application of scrambling code circuit, and can complete the setting of encryption circuit according to the specific situation. And, based on digital microwave communication, the applied antenna has very strong directivity. Therefore, in the case of deviation from the direction of the digital microwave rays, the microwave signal cannot be obtained.
2.3 Energy saving and consumption reduction.
Because digital microwave communication equipment does not occupy a lot of space, it has the characteristics of energy saving and consumption reduction.
2.4 It is easy to build a digital communication network.
In systems based on digital microwave communication technology, digital information can be transmitted, and different types of information can be controlled and transmitted through the application of computers.
Part 3. Development Analysis of Digital Microwave Communication Technology
3.1 Development Status of Digital Microwave Communication Technology
In the initial stage, microwave communication systems are all analog systems, which are similar to coaxial cable carrier transmission systems, and are the main transmission modes of long-distance transmission trunk lines in communication networks.
Generally speaking, in China, the transmission of TV programs between cities is by means of microwave transmission. At the end of the 1980s, in the process of transmission system, the application of synchronous digital series became more and more extensive, and the capacity of digital microwave communication system became larger and larger.
With the rapid development of science and technology, digital microwave communication technology has been widely used in the field of fixed broadband access. This shows that the digital microwave communication technology has excellent development prospects.
3.2 Development Direction of Digital Microwave Communication Technology
Due to the different characteristics of digital microwave communication technology itself, its development direction also presents diversified characteristics, which are as follows:
- Realize the improvement of QAM modulation level.
For the current digital microwave communication technology, in order to effectively improve its spectrum utilization, it is generally necessary to use multi-level QAM, that is, quadrature amplitude modulation.
At present, 512QAM is mainly used, and 1024QAM or 2048QAM may be used in the future. Based on this, there are also higher requirements in the design of the channel filter, requiring that the cosine roll-off coefficient can be maintained to a certain extent.
- Application of Trellis Coded Modulation Technology and Viterbi Detection Technology.
In order to effectively reduce the system bit error rate, it is necessary to use error correction coding technology with complex characteristics. However, using this technique reduces the utilization efficiency of the frequency band. Therefore, trellis-coded modulation technology plays a substantial role in it.
On the basis of using trellis coding modulation technology, it is also necessary to use Viterbi algorithm to complete decoding. At present, in the process of high-speed digital signal transmission, it is difficult to use this type of decoding algorithm.
- Application of adaptive time domain equalization technology.
In order to effectively reduce the inter-symbol interference rate, it is necessary to use adaptive time domain equalization technology, which has many advantages such as high performance and full digitalization.
At the same time, the use of this technology can also effectively avoid problems such as orthogonal interference and multipath fading to a certain extent.
- Application of multi-carrier parallel transmission technology.
In order to effectively reduce the rate of signaling symbols and effectively avoid the influence of propagation dispersion, the application of multi-carrier parallel transmission technology plays a substantial role.
At the same time, this technology can also effectively reduce the instantaneous interruption rate, which is generally reduced to 1/10 of that before the change.
In addition, with the development of digital microwave communication technology, nonlinear pre-correction of signal power amplifiers can also be widely used.
Part 4. Research on the application of digital microwave communication technology
Digital microwave communication has many characteristics, including convenient networking, short construction period and low cost. Under the current situation, digital microwave communication technology is widely used and has many functions. The specific performance is as follows:
4.1 It can be used as a backup and supplement for trunk fiber transmission.
Under normal circumstances, when the trunk optical fiber transmission system encounters natural disasters, point-to-point SDH microwave and PDH microwave can complete timely and effective repairs.
4.2 Can provide users with basic business information.
In some remote rural areas and islands, digital microwave communication technology can be effectively applied to further provide users with basic business information.
4.3 It can be used in short-distance feeder connections in cities. Including the connection between the communication nodes, the communication between the base station controller and the base station, etc.
4.4 Broadband wireless access can be achieved.
As an excellent communication technology, broadband wireless access technology has the characteristics of speed and convenience.
In the competition of high-speed data services, the technology also has certain application value. For example, LMDS technology is a local multi-point distribution business technology. This technology has the advantage of rapid start-up. It only needs to consume a low construction cost and can effectively complete the networking in a very short period.
As an excellent communication technology, broadband wireless access technology has the characteristics of speed and convenience.
In the competition of high-speed data services, the technology also has certain application value. For example, LMDS technology is a local multi-point distribution business technology. This technology has the advantage of rapid start-up. It only needs to consume a low construction cost and can effectively complete the networking in a very short period.
