WiMAX wireless broadband technology is difficult to split into frequencies (1)

The transmission of wireless technology is based on radio waves, which occupy a certain frequency band. In the era of resource shortage, frequency band resources are also not rich. This brings competition for our wireless technology. At present, there are a variety of wireless technologies, each of which has different standards. However, WiMAX wireless broadband technology is not optimistic in China.

In recent years, with the continuous development of WiMAX wireless broadband technology, the relevant standards are constantly mature, and device authentication is also underway. The application of WiMAX wireless broadband technology is getting closer and closer to us. However, the development of WiMAX wireless broadband technology is inseparable from appropriate frequency resources. In the wireless communication field, frequency resource policies will greatly affect the development of a wireless communication industry. The frequency planning of WiMAX wireless broadband technology first needs to analyze the bandwidth requirements of WiMAX services, including the analysis and prediction of the number of users, and the analysis and prediction of user data business types, bandwidth Requirement Analysis for different services. In addition, the system-level spectrum utilization in the actual application environment should be considered, including the business model, networking mode, slice configuration, frequency reuse technology, and interference problems.

In the standard of 802.16, no specific frequency and frequency interval are specified, but only 2 ~ Use of different frequencies in 66 GHz, 10 ~ 66 GHz for line of sight propagation, 2 ~ The 11 GHz band is used for non-line-of-sight transmission. If it is used to support mobility, it is recommended to use a frequency band below 6 GHz. We recommend that you use the 3.5 GHz and 5.8 GHz frequencies for fixed and nomadic frequencies in the WiMAX alliance, A 2.5 GHz or below 1 GHz frequency band is considered. WiMAX wireless broadband technology is cooperating with international organizations such as ITU to expand the spectrum available for WiMAX products. Since 802.16 is a new technology, most countries have not yet defined it in 2 ~ What is the 802.16e Distribution frequency in the 6 GHz band. The ITU is also discussing the future frequency of broadband wireless access, coordination issues with other businesses, such as satellites, and international roaming issues.

Theoretically, WiMAX wireless broadband technology requires the following frequencies. For fixed access, large channel bandwidth is required to support high-capacity transmission, and the frequency band is not sensitive. For mobile access, the channel bandwidth must be as large as possible and the available frequency band should be as low as possible, to reduce network deployment costs and improve service quality. Frequency is an important factor affecting the cost of mobile networking. For mobile WiMAX, the frequency problem is the cost problem.

I. China 2 ~ 6 GHz frequency division status

The World Radio Conference WRC92 in 1992 has divided the global 2 GHz frequency band: the land part is 170 MHz, and the satellite part is 60 MHz, the land business is divided into FDD frequency duplex) and TDD time duplex. FDD mode in China: 1920 ~ 1980 MHz, 2110 ~ 2170 MHz: 120 MHz in total; TDD mode: 1885 ~ 1920 MHz, 2010 ~ 2025 MHz: 50 MHz in total.

2300 ~ 2400 MHz: used for TDD business, is allocated to the TD-SCDMA frequency, there are now radar business.
2400 ~ 2483.5 MHz: ISM industrial, scientific, and medical frequencies. China's Radio Management Department stipulates that this frequency band is used as a shared band for wireless LAN, wireless access system, Bluetooth system, point-to-point or point-to-point spread spectrum communication systems, and other radio stations.

2483.5 ~ 2500 MHz: allocated to fixed and mobile businesses, but satellite radio measurement is currently the main business.
2500 ~ 2690 MHz: used for fixed services, fixed satellite services, and mobile-except aerial mobile services, satellite mobile services, Satellite Broadcast Services, and radio positioning services, but already allocated to third-generation mobile communications as extended frequency bands, in addition, China's radio frequency division CHN12 rules: 2655 ~ 2690 MHz frequency radio astronomy is also the main business, and is currently used in Beijing, Nanjing, Jiangyin, Jiangsu, and Guizhou karst areas. Other business may not interfere with it.

3000 ~ 3400 MHz: This frequency band can work in TDD licensed frequencies. Currently, China plans to use it for radio positioning, fixed, mobile, and business purposes, but it is rarely used.
3400 ~ 4200 MHz: it belongs to the C-band of satellite communication, and a large amount of microwave is in use.
4400 ~ 4990 MHz: According to CHN21, 4400 ~ The 4990 MHz fixed service is mainly used for large-capacity microwave relay trunk networks, but some radio astronomy services still need to be protected. Among them, 4950 ~ 4990 MHz for business use space research and earth detection services at once. At the WRC03 meeting, we strongly recommend 4940 ~ 4990 MHz is used for public protection and emergency services.
4990 ~ 5000 MHz: The main business is fixed, but there are still radio astronomy services.
5150 ~ 5725 MHz: used for radio navigation, satellite and earth detection, and radio positioning. However, at WRC03 ~ Fixed and mobile services are added by adjusting the radio service in the 5725MH band.

5725 ~ 5850 MHz: Open frequency band, which allows shared frequency bands of radio stations such as point-to-point spread spectrum communication systems, broadband wireless access systems, high-speed wireless LAN, Bluetooth technology devices, and vehicle wireless automatic identification systems.
5850 ~ 5925 MHz: it can be used for fixed, mobile, satellite fixed, and radio positioning. At the same time, it must protect radio astronomy in some areas, in addition, this frequency band is also recommended for public protection and emergency services at the WRC03 Conference. In this frequency band, there are also C-band satellite communications.
5925 ~ 6000 MHz: large-scale microwave is in use, and cband satellite communication is also available in this band.

Ii. Analysis of relevant frequency bands

According to the current situation of China's frequency division and the frequency requirements provided by related equipment manufacturers, 2.5 GHz, 3.3 ~ 3.4 GHz, 3.5 GHz, 5 GHz, 5.15 ~ The 5.725 GHz and 5.8 GHz frequencies are the focus of attention.

1) 2.5 ~ 2.69 GHz
According to the Radio Wave Propagation and spatial attenuation characteristics of mobile communication, the 2.5 GHz band is a good choice for mobile broadband systems. This band has good non-line-of-sight transmission capabilities, it can effectively improve the coverage distance of base stations, reduce the R & D costs of base stations and terminals, and truly make broadband wireless access products mobile. However, this frequency band is now divided into space services. At the WRC03 conference, it was also set as an extended IMT-2000 band, where satellite broadcast and radio positioning businesses were also involved. Therefore, it is difficult to use WiMAX wireless broadband technology in this band.