Microwave transmission is one of the most flexible, the most adaptable means of communication, with fast construction, small investment and flexible application, microwave transmission is not only widely used in mobile networks, but also favored by fixed network operators. Widely used in radio and television, security video surveillance transmission, control and so on. China also has the backbone of the national microwave link.
On December 4, 2013, the Ministry of Industry to China Mobile, Unicom, China Telecom issued Td-lte (4G) business license, the Chinese mobile communications market in 2014 entered the year of 4G network. June 27, 2014, the Ministry of Industry further to China Unicom and the Chinese telecom issued a hybrid network experiment FD-LTE license plate, marking the China Mobile Communication 4G Network will enter the high-speed development and construction stage.
4G Network Construction needs
According to China Mobile's 2014 4G construction target, 500,000 Td-lte stations will be built before the end of the year. Up to now, China Unicom and the Chinese telecom mixed network of cities have also been developed by their respective initial 16 cities to 40 cities. With the large-scale 4G network construction, the construction process is also facing more and more problems.
On the one hand, from the breadth of 4G network coverage to consider, as the 4G base station coverage is less than 3G base station, so 4G network LTE site will be more intensive. Among them, in order to meet the continuous 4G network coverage, will need to be in the existing site 4G coverage of the new site, while in some new sites, fiber resources shortage. Especially in the mega cities, such as Beijing, Shanghai, Guangzhou and so on, the progress and difficulty of optical fiber deployment can not meet the requirements of network construction, mobile return network resources are facing great pressure and challenges. On the other hand, from the depth of 4G network coverage, for data hotspot areas and coverage edge areas, in order to improve the user's perception and experience, based on Acer Station small cell station will be in the next phase of 4G construction more extensive deployment. The deployment of Small cell station will be more flexible, the coverage is smaller, the deployment density is larger, based on the Small cell station return scheme also put forward a new challenge to the network construction.
In the above case, the domestic operators have begun to integrate the microwave transmission solution into the 4G network construction planning. As an important solution for mobile return, microwave transmission products are widely deployed in global operators ' networks because of their compact structure, flexible deployment, fast installation and simple maintenance. With the extensive deployment of LTE network in the world and the development of microwave transmission technology in recent years, microwave transmission has played an increasingly important role in 4G network.
Large capacity large bandwidth technology
With the development and evolution of mobile communication network, microwave products are mainly used in 3G and 4G networks. Thanks to the development of chip technology and system technology, as well as more open frequency policies and resources, packet microwave product transmission capacity has greatly exceeded the previous generation of TDM microwave products. At present, the most advanced microwave products modulation and demodulation mode has been able to support up to 2048QAM, compared with the traditional TDM microwave maximum 256QAM modulation mode, the spectrum utilization efficiency increased by 40%. In addition, the E-band band (80GHz), which is used in the traditional frequency band for 56MHz or greater frequency bandwidth and the recent operator attention, makes the transmission capacity of microwave products further enhanced. Under the condition of 2048QAM modulation and 56MHz bandwidth, the microwave system on the traditional frequency band can realize the volume of the above 1Gbps in a frequency point by xpic technology. In the E-band band, due to its rich and clean spectrum resources, can be allocated greater bandwidth (such as: 250mhz~1.25ghz) to achieve a large volume of empty traffic, for example, in the E-band band, 256QAM modulation and 500MHz bandwidth conditions, Maximum implementation of 3.2Gbps of empty business transmission capacity.
Adaptive modulation and Demodulation technology and QoS function
According to the characteristics of 4G mobile network, microwave transmission equipment can receive various fading in the process of transmission through adaptive modulation and demodulation, and the performance of microwave system can be changed by modulation and demodulation when the transmission environment and conditions deteriorate, thus ensuring the normal transmission of the business. The bandwidth change caused by the change of modulation and demodulation, through the QoS function of the microwave system, realizes the classification processing of the different priority business. The 8-level QoS mechanism within the microwave equipment, including classification, scheduling, shaping, conflict avoidance mechanism, can be used to deal with the 4G business more finely and flexibly. By adjusting the length of each business queue, the delay and throughput of the service transmission can be optimized according to the type and nature of different business.
V-band Microwave Product Application
According to the global V-band (60GHZ) microwave product deployment, the main advantage is that the band can be used free of charge, reducing the cost of spectrum consumption; in 256QAM modulation and demodulation mode can support 400Mbps above business throughput. In addition, because the oxygen attenuation in the V-band band is very large, the microwave transmission distance is very limited (maximum about 300m), so the frequency multiplexing efficiency of v-band microwave is very high, the frequency interference between the microwave transmission link is very limited, Very suitable for the Smallcell station as a dense deployment of the return solution. Currently, NEC's commercially available V-band microwave products have been deployed across multiple carrier networks in 5 countries. The product integration is very high, the use of the entire outdoor product structure, built-in high gain flat antenna, microwave products, the total weight of only 5Kg, is very suitable for all kinds of environmental conditions of deployment, including streets, walls, road poles, bus stations, newspapers and so on.
High integration, low power consumption
With the full deployment and rapid construction of 4G network, power consumption has become one of the biggest problems in network construction, and the cost of network operation and maintenance due to the power consumption of equipment will be very huge. The new generation of microwave products on the basis of radio frequency technology and process development, the microwave system integration degree is increasing, the structure is simpler and smaller, in order to further reduce the power consumption of microwave products. Among them, NEC, with its leading RF technology and manufacturing process, released in 2013 the first Super compact and miniaturized handheld Microwave outdoor unit (IAG/IAP ODU), both in terms of volume, weight and power consumption are fully beyond the current market of similar products. Compared to the microwave products before NEC, the new outdoor Unit (ODU) will reduce the volume by 1/3, weight by 1/2, only 2 kg, power saving at least 30%, the minimum of only 18W.
Fronthaul Microwave Solution
At present, the new generation of microwave products can easily achieve the gigabit rate of transmission capacity. With the development of microwave technology and the opening of new spectrum resources, the transmission capacity of microwave products is further improved, the variety of products is more diverse, and the microwave application scene is more extensive. Rely on microwave products stable and reliable performance and large capacity transmission capacity, NEC released in 2014 the first E-band band CPRI Microwave products, applied to the distributed base station of the Baseband Processing Unit (BBU) and RF pull far module (RRU) between the wireless connection, providing a mobile network of the Future network ( Fronthaul) return to a new outdoor solution. NEC's CPRI Microwave products have a transmission capacity of 2.5Gbps to meet the Cpri Ver5.0 Option-3 (2457.6Mbps) rate requirements, provide a standard CPRI business interface, and can be used to solve Bbu+rru multi-channel transmission scheme. The introduction of CPRI microwave products makes the mobile network of operators more diversified and the structure of the network more flexible.
Diversified products, advanced technology and functions, stable system performance, simple and compact structure and ultra-low power consumption, strong environmental adaptability, rapid installation and convenient deployment, so that microwave products in the construction of mobile transmission network as an important means of transmission, by the operator's universal attention. In the construction of 4G network in the future, microwave products will play an increasingly important role for the network construction of operators to provide more choices and improve the efficiency of network construction.