Wireless Broadband access technology and its application analysis

1. Overview

Limited by the ability of 2G, 2.5G Wireless network, the development of mobile internet business is restricted. Recently, the rapid development of mobile network technology, 3G has been widely used, HSDPA technology has been gradually applied, mobile broadband has become the development trend of mobile communications, telecommunications operators on the mobile internet business is also more and more attention.

With the development of PDA and notebook computer, users want to be able to access the Internet anytime, a new market, "broadband wireless nomadic/mobile Access" is emerging.

Broadband wireless access technology for a new market for fixed and mobile communications convergence, it can provide broadband wired fixed access parallel to the wireless access business, support nomadic and mobile applications. It uses a Common Core network, business support and AAA system with broadband fixed access, with a speed of up to kilometers bits per second or even a few 10 megabits per second, with terminals mainly laptops and PDAs.

However, whether a new technology can be successful, in addition to its own advanced, to a large extent, still depends on whether there is a good business form and good business model, market users do not care about technology itself, but to see whether the launch of the business can be accepted by users, can bring profits to the enterprise. This is precisely the current problem that includes wireless broadband access technology, including many of the biggest problems of broadband wireless technology.

2, the wireless broadband business needs

The original purpose of wireless broadband access technology is mobile internet services, which are very suitable for mobile internet services in terms of transmission rate, flexibility, and cost. Mobile Internet content and service can also give full play to the technical advantages of wireless broadband access, is the carrier of wireless broadband access business development strategic direction.

Other such as VOLP business, Internet access services, etc., should be regarded as operators in order to obtain short-term benefits of the tactical action.

Of course, mobile internet business is not a fixed internet business on the mobile Web simple replication, mobile terminals, mobile, portable and personalized features such as give the mobile Internet more content.

In fact, one of the private terminals will be more conducive to the development of the Internet, more conducive to the embodiment of the Internet for everyone to participate in development, everyone to participate in the concept of innovation, more in line with the essential characteristics of Web2.0.

Therefore, the mobile Internet business content will be richer, more humane, will be more than the current Internet to change our way of life.

Undoubtedly, providing wireless Internet access is an important business form of wireless broadband access technology. In addition, with the development of new technology, the focus of mobile communication service is moving from channel class such as voice and Internet access to content and service class business. Wireless Broadband access technology will be mainly used for Internet applications.

The value of the Internet is still a vast amount of information without boundaries, at the same time with openness, reciprocity, transparency, so the core network, wireless access network as part of the Internet infrastructure also need to comply with this principle, from these principles can be seen in the future of the Internet only one, WAP is only terminal and network capacity when the transition, Does not replicate a system for wireless internet, but adds new personality applications to users ' wireless features in the Internet.

At the same time, we can see that wireless broadband access technology and mobile internet has a good match, will be widely in the network construction plays an important role.

3, Wireless Broadband technology Progress

The wireless broadband access technology mainly has two kinds of technology system, one kind is the cellular mobile communication technology, to 3G, HSDPA, HSUPA, LTE, AIE, 4G and so on direction development; Another kind of wireless technology is MMDS, WiFi, WiBro, WiMAX, Mcwill technology.

The systems suitable for nomadic/mobile broadband wireless access applications are basically OFDMA. Ofd-ma combines time division and Frequency Division multiple access technology, client terminals can use only a few carrier carriers in the uplink, so the transmit power is concentrated in these carrier carriers, can improve the signal-to-noise ratio of more than 10 db, to meet the needs of the notebook computer 0dB antenna room reception.

3.1 Mobile cellular broadband access Technology

Mobile data service is basically a private network, download rate below lookbit/s. Smartphones can be plugged into the Internet, but the performance is not ideal for mainstream applications. 3GPP and 3GPP2 have realized that their current system provides Internet access to the limitations of the business, trying to in the original system framework, first in the downlink link in the use of packet access technology, greatly improve the IP data download and streaming media rate.

The reason why 3G system is inefficient in supporting IP data service is that the structure of connection-oriented fixed bandwidth does not meet the demand of burst-type IP data service.

To this end, 3GPP in the R5 system has increased the high-speed Downlink packet Access (HSDPA) (known as 3.5G), the rate can reach 10mbit/s above, and then further in the R6 to increase the high-speed uplink packet Access (HSUPA), the core network is also evolving to the full IP network. To compete with WiMAX, 3GPP developed a long-term evolution (LTE) program (known as 3.9G) at the end of 2004.

3.2 Wireless Broadband access Technology

Broadband Wireless access (broadband Wireless ACCESS,BWA) technology does not have a common definition, generally refers to the use of high efficiency wireless technology in broadband access networks, wireless access to users with the technology. The IEEE 802 Standard group is responsible for the development of unlimited broadband access BWA various technical specifications, according to the scope of the broadband wireless access divided into: Wireless domain network Wpan (Wireless Personal area Network), Wireless LAN WLAN, wireless metropolitan area Network Wman, Wireless wide Area network Wwan.

Among the more representative is the WiFi and WiMAX technology, although not commercially successful, WiFi has been a large-scale application, this is not introduced, where the relevant technology has WiBro and Wcwill technology.

McWiLL (multi-carrier Wireless Internet Localloop) is the proprietary technology of the company, and is currently developing SCDMA R4 and R5 versions, It is a wireless broadband metropolitan area Network access system which is developed for high-speed data transmission after the SCDMA wireless local loop access system. The standard is already more mature for network devices and user devices, but private standards are expected to hinder development, and WiBro has become a subset of WiMAX to the WiMAX camp.

3.3 Comparison of two kinds of wireless broadband technology

WiMAX for the broadband wireless access market, 3G Mobile communications for mobile phone-oriented cellular communication systems, generally speaking, they are complementary relationship. However, when the 3GPP development of broadband wireless access market HSDPA, especially after the development of LTE, there is a competitive relationship.

From the above analysis we can see WiMAX and 3GPP LTE is facing the same market, indicators are similar, the use of technology is similar, can be said to be the same.

3GPP decided to develop LTE is a strategic decision that has far-reaching implications for its future development. Although the current development of LTE can get rid of the original structure of the system is still questionable, but its members are currently 3G mainstream operators, strong and have 3G frequency license, their development of LTE even if the performance of some poor, in the broadband wireless access market still has a strong competitiveness, And once they have LTE, they will no longer consider using competing technologies such as WiMAX.

In addition, LTE uses 3G frequency, even can use 2G frequency, has the good penetrating ability, the safeguard system has the high performance price ratio.

WiMAX is the development of broadband wireless access technology by the IT industry, due to the lack of the original system constraints, the most suitable for the broadband access market demand. Due to the emergence of LTE, WiMAX operators may be used mainly fixed network operators and new operators.

It equipment manufacturers such as Intel are a firm and powerful supporter of WiMAX, who want to enter the broadband wireless access market via WiMAX. Intel's commitment to bundling WiMAX in future laptops enhances WiMAX's ability to compete.

4. Network deployment of Wireless broadband network

WiMAX and LTE core technology is basically consistent, in network capacity and network deployment is also close to, some time ago, the development of WiMAX technology more dominant, but the future of LTE is more optimistic. But what kind of technology will be used in the future, what kind of technology would become mainstream, will depend on the power of equipment manufacturers and the degree of perfection of the industrial chain. This article takes WiMAX technology as an example to carry on the network deployment discussion.

4.1 Network capability

At present, WiMAX bandwidth flexibility and frequency is not yet determined, assuming a parameter configuration to analyze the IEEE 802.1 6e network coverage capability, with 2.5GHz band, 10MHz bandwidth for example. In the link budget, consider the following factors: Because of the influence of shadow fading, in order to guarantee certain coverage probability, we must reserve the shadow fading margin, take the shadow fading reserve 6dB; The fast fading reserve is the power margin reserved for power control, and the power control can resist the fast fading to some extent, Therefore, the power control needs to reserve the capacity margin.

In the 802.16E network, because the terminal can move access, and mobile will bring a certain decline, through power control can make up for this decline, so need to give power control to leave a certain amount of margin, but due to the 802.16E network power control frequency is relatively low, so do not need to reserve too much fast fading reserves, here take 2dB;

WiMAX network exists in the neighborhood and the same frequency interference, the size of the interference and the size of the station, frequency planning, antenna orientation and other factors, in order to make the area of serious interference in the region to normal communication, it is necessary to leave a part of the margin. If the frequency multiplexing mode is 1/3/1, uplink reserve interference reserves 3dB, downlink 2dB;

If the frequency multiplexing mode is 1/3/3, the jamming reserve can be reduced to 0.2dB, but it will result in lower spectral efficiency. The COST-231 Hata model is used in the link budget.

Total gain of 802.16e downlink (QPSKL/2) For 148.67dB, if the reserve line-of-sight transmission is not considered, assuming the terminal antenna height of 1.5m, base station antenna height 32m, using the COST-231 model to predict the radius of the rhyme cell is 1.70km, if the 9.6dB reserves, the calculated radius of the cell is 0.90km. For the non visual Range environment, considering the 10dB penetration loss, the maximum allowable path loss is 129.1ldB, and the prediction cell radius is 0.47km.

Total gain of uplink (QPSKI/2,1/16) For 148.41dB, if the storage and line-of-sight transmission is not considered, assuming the terminal antenna height of 1.5m, base station antenna height 32m, with the COST-231 model prediction of the cell radius of 1.67km, if the reserves of the 9.6dB, the calculated radius of the cell is 0.83km; For the non visual Range environment, considering the 10dB penetration loss, the maximum allowable path loss is 126.8dB, and the prediction cell radius is 0.43km.

Considering the non visual range, the coverage distance is about 500m in the urban environment of Metropolis, which can meet the practical requirements. When designing a wireless network, we should not only consider the coverage distance, but also consider the network capacity and network bandwidth, which is usually more important than the former for the purpose of broadband access. If 3G and b3g provide broadband data services in densely populated areas, their station spacing will not be less than 500m.

4.2 Network costs

Because WiMAX technology is more concise than the cellular network system, WiMAX's full IP technology architecture is an important factor for its cost advantage.

At present, the WiMAX cost is lower than other 3G systems are the main factors of the following analysis:

1. Uniform International Standards

WiMAX has a unified international standard, in the global market conditions, not only promote the development of technology, but also to ensure that the market size, while reducing the industrial chain at all levels of product costs. At the same time, Low-cost, easy to implement the advantages, so that emerging operators have the opportunity to quickly cut the market, can bring operators to reduce network deployment and operating costs and accelerate the cost performance of the public platform.

2. Different ways of development

WiMAX does not have to pay a substantial cost to maintain compatibility with previous systems. In the system network structure, do not adhere to the old business restrictions, can be fully adapted to the future Communication System network architecture. This architecture will greatly improve the system equipment and terminal hardware and software economies of scale, but also reduce the operator's investment risk and operating costs.

3. Cost of patent use

WiMAX has not fully defined its IPR policy, but WiMAX patents dispersed, will not appear one or a handful of the core technology control, the situation of wild speculations.

4.3 Policy frequency factors

In terms of frequency resource allocation, WiMAX and 3G, 3G expansion and Evolution Band and Wi-Fi and the planned use of the frequency band and the planned 4G frequency of the conflict, which will inevitably face severe frequency planning and coordination issues. Strategic positioning is the premise of WiMAX frequency allocation, any strategic positioning must be closely linked with the domestic industry development and competition pattern. If WiMAX positioning as a 3G supplement, it shows WiMAX into the dream of the mainstream market in China, but to WiMAX frequency allocation and regulation brings new problems.

According to China's frequency allocation status, WiMAX frequency planning will focus on the 3.5GHz band. In this band, there are 3300. 3399.5MHz and 3531~3600mhz A total of 168.5MHz has not yet been allocated to the communication frequency, if taken into account 3399.5 of the assigned bidding. 3531MHz Ground fixed access frequency, from 3300~3600mhz a total of 300MHz frequency, to become the industry's eye-catching WiMAX target frequency.

5. Business model Analysis

Not all businesses that are popular with users can bring profits to the business. Fixed on the internet a lot of business, such as instant messaging, Peer-to-peer services, although the development is good, but because of the lack of effective business model, so far fixed network operators have not received the due benefits. The global explosion in WLAN has been widely welcomed by the public, but operators who have made a high-profile expansion of WLAN hotspots have not profited directly from it.

To this end, the wireless broadband access business design must have a reasonable and effective business model of protection, otherwise it will face similar internet and WLAN dilemma awkward situation.

We take Beijing as an example to introduce the network construction, business analysis, the assumption of 2.5GHz in Beijing's WiMAX network, covering the four ring (temporarily excluding southwest corner) of the central city, airport and Airport Expressway. Provide high-speed and inexpensive data services for individuals and business users, including Internet access, data transmission and multimedia. At the same time provide some public security support for the government.

The network consists of 25 base stations, each covering a radius of 2.0km, an area of 10.8 square meters. 21 base stations are deployed in the four rings, 1 at the airport and 3 sectors per base station. From the four-yuan bridge to the airport a total of 16kin of highway deployed 3 base stations, 2 sectors per base station. A total of 72 sectors are required for the entire network. Each sector is connected to the core network through a E1 line.

According to different urban business needs, 30% of the sector with 5 E1 lines, 40% of the sector with 3 E1 lines, the remaining 30% with a E1 line, a total of 216 E1 line. Based on the original system, the core network is upgraded and modified to meet the requirements of WiMAX network. It is assumed that the base station equipment and antenna and feeder are calculated with an average of 78 000 yuan per sector, a total of 72 sectors, and the design, construction, supervision and infrastructure costs are calculated according to 15% of the base station equipment. Transmission line rental includes rent of 216 E1 lines (paid at the beginning of each year), the total cost is about 15 million.

After the network is put into use, the annual cash flow includes the user fee of the users and the cost of running and maintenance. Equipment maintenance costs in accordance with the base station equipment cost of 1% calculation, plus transmission lines, such as about 9 million a year.

After network deployment, mainly provide access services. The entire WiMAX network business is divided into personal data Services and enterprise data Services. In the case of personal data Services, the first year assumes 13,700 users. For reference to ADSL and e-line fee, the introduction of the following five kinds of packages: 5 yuan/month, 10 yuan/month, 50 yuan/month, 100 yuan/month, 180 yuan/month, the estimated users are 5 000, 5 000, 2 000, 1 000, 700.

On the other hand, considering the enterprise data Service, the enterprise users are estimated to be 1/200 of the individual users, while enterprise users use the data service more than the individual users, and the income ratio is 2:3. The first year total income is about 9 million.

Assuming that through the development of more users each year, income increases each year, followed by a four-year growth rate of 10%, 12%, 15% and 15%. The operation and maintenance costs of the network remain unchanged. Assuming that the annual return on capital investment is 12%, the total net present value for the fifth year exceeds the project deployment investment.

6. Concluding remarks

In 20, in the late 90, fixed communication service is also the main support for the revenue of telecom operators, but also the main means of communication, but mobile communications replaced fixed network has been revealed, the next decade ushered in the development of mobile communications, although the mobile voice business has been the support of mobile operators, Mobile data services are more likely to replace, but the mobile data business has always been difficult to escape the fate of less substantial profit, the past to see a football game long to attack, often frustrated, I hope mobile data business will not be so.

Today we see the content and application of the Internet become an indispensable part of our life and work. Perhaps the personal multimedia service, information service is the ultimate demand, the pursuit of information services anytime, anywhere and happy experience is the human instinct, and communication is always online is not necessary. This has won development opportunities for wireless broadband access technologies that provide Internet access anytime, anywhere.