What is WiMAX?

Worldwide Interoperability for Microwave Access (WiMAX) is evolution from Broadband Wireless Access (BWA) previously. If the previous BWA technology still proprietary, the WiMAX technology is open standard. It means communication between different WiMAX equipments still can be done (unproprietary).

WiMAX technology developments do in some steps or get an evolution. According to the standard, WiMAX technology was arranged in IEEE 802.16. Its divided into many categories, are IEEE 802.16a for BWA standard that has not been open standard or usually called as Pre-WiMAX. In the next, its standard will be developed to be IEEE 802.16d for fixed/nomadic WiMAX. While for WiMAX mobile will be arranged in IEEE 802.16e has been ratified in the year end of 2005. Such as picture 1.

Picture 1. WiMAX Standard Development

Beside evolution in access capability, there is evolution in CPE. In the first step, CPE WiMAX equip4ment, the Fixed Outdoor has developed become fixed indoor, portability (nomadic), and mobile. Fixed Outdoor is CPE Equipment which contains 2 units; they are outdoor unit which comprises radio and antenna, and indoor unit with interface to subscriber terminal. In Fixed Indoor type, CPE equipment only comprises one indoor unit that has been consist of radio, antenna, and port user interface. Generally for this type, user can install the CPE by himself (self installation).

For the next step, CPE has not been independent equipment recently but its grouped in subscriber terminal such as in laptop and PDA. In this step, CPE WiMAX portable has installed permanently in the terminal as well as CPE WiFi. And the last is mobile devices. Added eminences are higher portability beside more compactable terminal size. In this step WiMAX terminal is handphone. By the development of CPE WiMAX evolution, automatically it also will effect to the targeted market.

WiMAX Application

WiMAX can be used for WiMAX backhaul itself, hotspot backhaul, and the other technology backhaul. In WiMAX context as backhaul of WiMAX, the application similar with BTS functions as repeater to enlarge WiMAX coverage. While as the other technology backhaul, WiMAX can be used as cellular backhaul. And usually if hotspot used many ADSL line as backhaul, because of limited cable network, WiMAX can be used as hotspot backhaul.

Picture 2. WiMAX as backhaul

WiMAX can be used as Last Mile technology to serve broadband needs of customer. Both individual subscriber and business can be served by WiMAX technology.

WiMAX as service provider of personal broadband can be used for 2 targeted market, are nomadic and mobile. For nomadic solution, usually movement level from WiMAX user is rarely and if it moves, it will be move with low speed. The equipment also not as simple as mobile application. For mobile application, WiMAX mobile user can be mobile with terminal WiFI such as notebook, PDA, or smartphone.

Architecture

One of sample configurations for WiMAX as solution of service provider access that described as in the picture below.

Picture 3. Configuration of Service Provider Access Network

From the explanation above, for a while can be concludes that WiMAX is technology which has enough well capability in data speed, application for user and network flexibility. But it has to be analyzed the other side of the implementation.

Technology Analyze

If in the early communication era, data which through by wireless network both cellular and fixed is short message service (SMS) GPRS data or CDMA2000 1X, mobile banking application, and download content, so for the next decade, it has estimated that broadband service will become most wanted service by subscriber. From various study by consultant firm and operators in advanced state, the services are 3G (third generation), internet on wireless, mobile TV, mobile video on demand, and mobile video conference. It will cause less different between given service by wireline and wireless network.

Global Spectrum Allocation

WiMAX is new global standard so in the world wide still need agreement for spectrum allocation. In each country through their regulation recently assume WiMAX importance as core utility intensively. Therefore the regulator is busy to regulate WiMAX frequency and existing frequency allocation. The table below is allocation frequency that has been used by world wide WiMAX operator.

Table 1. Global Spectrum Allocation

Frequency tape and bandwidth has to be set up with availability condition of frequency spectrum in each user state. Here is profile of each frequency tapes.

Table 2. Release 1- Profile of WiMAX Mobile system

WiMAX-certified product has not been implemented commercially yet in the world. Maybe the first state that will present it is Korea with the implementation of WiBRO with portable terminal for mobile application. Its product use 2.3 GHz frequency with 8.75 MHz bandwidth by using single input single output antenna.

Regulation Aspect

Because WiMAX frequency is new frequency, so each government in every state through their regulator are busy to determine WiMAX frequency allocation that has been set up with existing frequency. Indonesia has seriously discussed for the allocation. Government through Post and Telecommunication Department issue white paper about frequency arrangement for BWA operation necessity such as in 2.3 GHz, 2.4 GHz, 2.5 GHz, 3.3 GHz, and 3.5 GHz.

Satellite operator and Association of Indonesian Satellite do not agree with the idea of WiMAX frequency that will be allocated in 3.5 GHz because it has been placed for satellite frequency usage. Appropriate with ITU, its frequency is assigned as frequency of fixed satellite services for space link to the earth. Satellite that has been used this is TELKOM-1 satellite (owned by TELKOM) and Palapa-2 satellite (owned by Pacific Satellite Nusantara/PSN) and generally used for VSAT and DTH.

In 2000, the regulator has issued regulation that those frequencies can be shared for BWA and satellite usage. But in the operational obviously found many interference disturbances that were received by satellite earth station. Therefore, canal allocation with 25 MHz in 3.5 GHz width finally reduced becomes 5 MHz. And nowadays government will present auction of BWA operation frequency license in 2.3 GHz for whole of Indonesia that based on regional amount of 3 blocks with 15 MHz in each block. In a whole world frequency tape that becomes most wanted by the operator is operated in 3.5 GHz. It means equipment that operated in the frequency will be cheaper than equipment that operated in another frequency included in 2.3 GHz.

License Number

Analysis report Maradevis on January 2006; organization of analysis research and telco market; said that WiMAX licensed holder more than 3G licensed holder in whole regional (North America, Europe, Asian Pacific region (APAC), Central America/Latin America region (CALA)). Accumulation of WiMAX licensed holder is 721 while 3G licensed holders are 106.

Picture 4. Number of Licenses Holder

Majority of WiMAX licensed holder is regional license while for 3G is national license, so WiMAX market more fragmented than 3G.

Cost Per Hz

Average cost per Hz of 3G spectrum more expensive than cost per Hz of BWA/WiMAX spectrum. In Europe average cost per Hz of 3G spectrum is multiply 1000 expensive than WiMAX. Maybe it because of telecom bubbles in there. Another reason is WiMAX licensed is auctioned only for fixed application, so its market will be fewer than 3G mobile services.

Picture 5. Comparison Graph

Coverage Service

Open air radio transmission characteristic will get attenuation of free-space loss (FSL) that becomes function of frequency and distance. Further distance between transmitter and receiver cause lower signal can be received by user because the attenuation will be greater. Higher operation frequency that used will cause higher attenuation.

Picture 6. Cell Radius Comparison between WiMAX and 1xEVDO

WiMAX Forum is discussing WiMAX standard for Fixed BWA (FBWA), portable application and mobile BWA. For portable and mobile BWA application until now has not been yet a certified product that presented commercially in the world. For the first time, it will be presented in Korea with WiBRO system use 2.3 GHz frequency with 8.75 MHz Bandwidth.

Picture 7. Comparison Throughput uses MIMO

WiMAX performance be better when the system use antenna multiple input multiple output.

General Capabilities

Generally WiMAX capabilities can be analyzed as follow:

§ Hand Off capability

Especially for Portable and mobile WiMAX, Hand off seamless will be hard to be done because WiMAX core network component not to be built as mobile system at the first.

§ Power Control

Good power control is needed in reverse link to give feedback to the transmitter about data speed that can be received by user. In WiMAX technology, message based power control still weak.

§ Battery Power Consumption

Idle state duty cycle that was used in WiMAX system 9-14 times higher than in 3G cellular so used mode sleep operation to save battery become not efficient but wasteful.

Terminal Availability

Terminal availability also be a part of succeeded telecommunication service presence. As its plan, WiMAX client terminal will be embedded inside consumer goods such as note book computer, smart handset, PDA, etc. Because the technology get support from many parties such as Intel, Motorola, Samsung, and the others where no most dominant part in forum, so possibility of WiMAX terminal availability will be easier to be reached.

Picture 8. Availability of WiMAX Terminal

Amount of Base Station

Biggest component in wireless network investment is base station infrastructure. Amount of user, wanted performance level, and wide coverage service are three factors that determine amount of base station that require to be presented. Remember that BWA system use higher frequency than 3G generally it will need more base station to cover service area, amount of user, and similar network availability.

Picture 9. Base station cell number between 3G and WiMAX

Picture above shown calculation of needed base station number by using Coushatta propagation model assumption in 1900 MHz, 2500 MHz, and 3500 MHz frequency.

CONCLUSION

Advantages

§ WiMAX is broadband wireless access technology which offer open standard with fixed and mobile (portable) application.

§ WiMAX license based on regional not national such as 3G so license cost is cheaper and finally easy to get in the market.

§ WiMAX terminal will be embedded in consumer goods such as computer notebook, smart phone, and PDA. Because it is supported by many parties who has authorization, possibility the WiMAX will be received in the market is easier.

Weakness

§ Because use high frequency spectrum, WiMAX coverage service less than 3G so needed base station number to cover similar area needed more base station number.

§ WiMAX frequency allocation needs adjustment to the existing frequency allocation in each country. Varicosity of allocation frequency cause equipment price be expensive.

§ Capability: WiMAX for mobility will not as well as cellular system and the battery consumption is more wasteful.

RECOMMENDATION

§ Government has to be strict when issued regulation of WiMAX frequency allocation in order to make it does not stack to the existing telecommunication network. Shifted 3.5 GHz frequency has been used by satellite operator for BWA frequency allocation will cause bad impact to the state because looking for satellite frequency substitute is harder than terrestrial frequency.

§ Government has to support telecommunication and information inhabitants born by facilitating woman presence in Indonesia because its relatively cheap so it more possible to be presented by small operator.

§ BWA operator has to consider coverage service which suitable with user demands exactly because if it does not match will be needed more base station number so the investment will be not efficient.

REFERENCES

1. DitJen POSTEL, “Penataan Spektrum Frekuensi Radio Layanan Akses Pita Lebar Berbasis Nir Kabel”, KOMINFO, Nopember 2006.

2. “Broadband Wireless Access Options”, Qualcomm Inc., Oktober 2006.

3. Doug Gray, “Mobile WiMAX: A Performance and Comparative Summary”, WiMAX Forum, September 2006.

4. Patrick Adhiatmadja, “Wireless Broadband: The Future, today”, Motorola Asia, Nopember 2006.

5. Kajian WiMAX, TELKOM RDC, 2006.

6. Various sources