JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN ELECTRONICS AND COMMUNICATION ENGINEERING
PERFORMANCE ANALYSIS OF WiMAX NETWORK WITH ADVANCE ANTENNA TECHNIQUE (MIMO)
1 DIPEN G. PATEL, 2 PROF. ANOOP SINGH POORINIA,
1 Student, M.Tech. Rajasthan Institute of Engg. & Tech. Jaipur ,Rajasthan, India
2 Director, Rajasthan Institute of Engg. & Tech. Jaipur, Rajasthan. India
,
ABSTRACT: This paper present the performance analysis of WiMAX network with multiple antenna technique (MIMO), in which WiMAX is a second generation protocol that allows for more efficient bandwidth use, interference avoidance and is intended to allow higher data rates over long distances. WiMAX (Worldwide Interoperability for Microwave Access) is a telecommunication technology that provides wireless transmission of data and it is a great alternative to fixed broadband connections such as cable or DSL. The technology is based on the IEEE 802.16 standard (called Broadband Wireless Access). WiMAX is led by the WiMAX Forum, a global organization of manufacturers and operators who share knowledge and developments to ensure compliance and international compatibility in WiMAX technology as per the IEEE 802.16 standard. This paper is on of the foot steps towards technical contribution in the world of wireless communication. The advanced multiple antenna technique makes it very conducive to other technologies, such as antenna diversity implementation ubiquitous. This paper starts with the introduction to WiMAX and comparative analysis with other wireless techniques. In the second phase, the performance analysis of WiMAX system is discussed. In the third phase, the physical layer of WiMAX system with MIMO technique has been elaborated and analyzed with simulation results.
KEYWORDS- WiMAX, MIMO, AAS, Wi-Fi, 4G
ISSN: 0975 –6779| NOV 11 TO OCT 12 | VOLUME – 02, ISSUE - 01 Page 250
JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN ELECTRONICS AND COMMUNICATION ENGINEERING
1. INTRODUCTION
The increasing demand in wireless services is resulting from use of digital networks as a next generation wireless communication networks with higher capacity. The increased reliance on computer networking and the internet has resulted in a wider demand for connectivity to be provided “any where, any time” leading to a rise in the requirements for higher capacity and high reliability broadband wireless telecommunication systems. WIMAX may be seen as the fourth generation (4G) of mobile systems as the convergence of cellular telephony, computing, internet access, and potentially many multimedia applications become a real fact. WIMAX is considered today the most interesting opportunity, able to provide radio coverage distances of almost kilometers and data trough put up to 70 Mbps, and complete wired network architectures, ensuring a flexible and cheap solution for the last-mile, the interoperability is a very strategic issue, on which equipment cost and volume of sales will be based. Operators will not be bound to a unique equipment supplier, as the radio base stations will be able to interact with terminals produced by different suppliers. Operators can benefit of suppliers’ competition in terms of costs and innovation.
2. RELATIONSHIP WITH OTHERWIRELESS TECHNOLOGIES
Wireless access to data networks is expected to be an area of rapid growth for mobile communication systems. The huge uptake rate of mobile phone technologies, WLANs and the exponential growth that is experiencing the use of the Internet have resulted in an increased demand for new methods to obtain high capacity wireless networks.
WiMAX is expected to have an explosive growth, as well as the Wi-Fi, but compared with the Wi-Fi WiMAX provides broadband connections in greater areas, measured in square kilometers, even with links not in line of sight. For these reasons WiMAX is a MAM, highlighting that “metropolitan” is referred to the extension of the areas and not to the density of population, But Wi-Fi and WiMAX are not competing technologies. While WiMAX can provide high capacity internet access to residences and business seats, Wi-Fi allows to extension of such connections inside the corporate sites buildings.
In any case, both WLAN and cellular mobile applications are being widely expanded to offer the demanded wireless access. However, they experience several difficulties for reaching a complete such as bandwidth, coverage area, and infrastructure costs.
As shown in fig.2, Wi-Fi provides a high data rate, but only on a short range of distances and with a slow movement of the user. On ht e other hand, cellular offers larger ranges and vehicular mobility, but instead, it provides
Fig 1 Comparative Analysis
Lower data rates, and requires high investments for its deployment. WiMAX tries to balance this situation.[7]
WiMAX fills the gap between Wi-Fi and cellular, thus providing vehicular mobility, and high service areas and data rates.
Fig 2 Relationship with other wireless technologies
3. WiMAX STANDARDS
WiMAX is a broadband wireless standard that enjoys widespread support from both the computer and telecom industries worldwide, making this technology particularly cost effective. Converged networks will likely connect users via the least-cost bandwidth path that service their usage demands. In rural areas without other broadband options, WiMAX-to-the-home connectivity will likely play the major role in providing “multi-play” services including voice, data and video. In urban environments the role of fixed-WiMAX will likely be more as backhaul for Wi-Fi and other WLAN technologies.
In order to provide interoperability among the various technologies the WiMAX forum, an industry body founded in 2001 to promote conformance to standards this wireless network. WiMAX developments have been moving forward at a rapid pace [8]. The initial standardization efforts in IEEE 802.16.Standards for Fixed WiMAX (IEEE 802.16. Standards for Fixed WiMAX (IEEE802.16-2004) were announced as final in 2004, followed by Mobile WiMAX (IEEE 802.16e) in 2005.[3]
In Europe, the standards for wireless MAMs were formalized under the ETSI as HiperMANs. There were also based on IEEE 802.16 standards but did not initially use the same parameters (such as frequency or number of sub-carriers). These were later harmonized with the WiMAX[1]
Fig 3 WiMAX Standards Evolution
Standards. The IEE 802.16d standards provide for fixed and nomadic access, while the 802.16e standards also provide mobility up to speeds of 120 kilometers per hour.[9]
4. WiMAX ARCHITECTURE
Figure 4 shows IEEE 802.16 Network Architecture BS (Base Station) and SSs (Subscriber Stations) All data traffic goes through the BS, and the BS control the allocation of bandwidth on the radio channel. During a communication, all the information coming from a SS go to the BS and are retransmit to the right SS. Base stations (BS) can handle thousands of subscriber stations (SS).[8]
Fig 4 WiMAX Architecture
Two type of link are defined:
• The downlink: From the BS to the SS.
• The uplink: From the SS to the BS.
A .WiMAX actually can provide two forms of wireless service
• There is the non-line-of-sight - Wi-Fi sort of service, where a small antenna on the computer connects to the tower. In this mode, WiMAX uses a lower frequency range -- 2 GHz to 11 GHz (similar to Wi-Fi).Lower wavelength transmissions are not as easily disrupted by physical obstructions -- they are better able to diffract, or bend, around obstacles.
• There is line of sight service, where a fixed dish antenna points straight at the WiMAX tower from a rooftop or pole. The line-of-sight connection is stronger and more stable, so it's able to send a lot of data with fewer errors. Line-of-sight transmissions use higher frequencies. At higher frequencies, there is less interference and lots more bandwidth.
5. WiMAX TOPOLOGIES
The IEEE 802.16 standard defines two possible network topologies
• PMP (Point-to-Multipoint) topology
• Mesh topology or Mesh mode
Fig 5 WiMAX PMP Topologies
The main difference between the two modes is the following: in the PMP mode, traffic may take place only between a BS and its SSs, while in the Mesh mode the traffic can be routed. Through other SSs until the BS and can even take place only between SSs. PMP is a centralized topology where the BS is the centre of the system while in Mesh topology it is not. The elements of a Mesh network are called nodes, e.g. a Mesh SS is a node. In Mesh topology, each station can create its own communication with any other station in the network and is then not restricted to communicate only with the BS. Thus, a major advantage of the Mesh mode is that the reach of a BS can be much greater, depending on then number of hops, until the most distant SS. On the other hand, using the Mesh mode brings up the now thoroughly studied research topic of ad hoc (no fixed infrastructure) network routing.[11]
When authorized to a Mesh network, a candidate SS node receives a 16-bit Node ID (Identifier) upon a request to an SS identified as the Mesh BS. The Node ID is the basis of node identification. The Node ID is transferred in the Analysis of MIMO based WiMAX Simulation For Next Gen Wireless Communication Mesh sub header of a
Fig 6 WiMAX Mesh Topology
Generic MAC frame in both uncast and broadcast messages. First WiMAX network deployments are planned to follow mainly PMP topology. Mesh topology is not yet part of a WiMAX certification profile (September 2006).[5] It has been reported that some manufacturers are planning to include the Mesh feature in their products, even before Mesh is in a certification profile.
6. SILENT FEATURE OF WIMAX
A. IP-based architecture
Wi-MAX defines a flexible all-IP-based network architecture that allows for the exploitation of all the benefits of IP. The reference network model calls for the use of Ip-based protocols to deliver end-to-end functions, such as QoS, security and mobility management.
B. Very high peak data rates.
WiMAX is capable of supporting very high peak data rates. Provide high-speed Internet access to home and business subscribers, without wires as high as 70Mbps when operation using a 10-66GHz wide spectrum.
C. Large coverage area
Allows communications over long distances than WiFi, and a greater bandwidth means it provides wide coverage and high speed compared to Wi-Fi. Theoretically Cover approximately 40 ~ 50 Km (30 miles)
D. Orthogonal frequency division multiple access (OFDMA)
Mobile WiMAX uses OFDM as a multiple-access technique, where by different users can be allocated different subsets of the OFDM tones. OFDMA facilitates the exploitation of frequency diversity and multi user diversity to significantly improve the system capacity.
E. Adaptive modulation & coding (AMC)
WiMAX supports a number of advanced signal processing techniques to improve overall system capacity. These techniques include adaptive modulation and coding, spatial multiplexing, and multi user diversity.
F. Link-layer retransmissions
For connections that require enhanced reliability, WiMAX supports automatic retransmission requests (ARQ) at the link layer. ARQ enabled connections require each transmitted packet to be acknowledged by the receiver. Unacknowledged packets are assumed to be lost and are retransmitted.
G. Support for advanced antenna techniques
The WiMAX solution has a number of hooks built into the physical-layer design, which allows for the use of multiple-antenna techniques. WiMAX offers very high spectral efficiency and variety of radiation patterns, particularly when using higher order MIMO solutions.[4]
H. Quality-of-service support
The WiMAX MAC layer has a connection-oriented architecture. WiMAX has a very flexible MAC layer that can accommodate a variety of traffic types, including voice, video and multimedia and provide strong QoS.
I.OFDM-based physical layer
The WiMAX physical layer is based on OFDM, which is an elegant and effective technique for overcoming multipath distortion.
7. WiMAX OPERATION
WiMAX could be used to set up a back-up or even primary communications system that would be difficult to destroy with a single, pinpoint attack Figure7 shows WiMAX operation and gives idea about how WiMAX works. A cluster of WiMAX transmitters would be set up in range of a key command center but as far from each other as possible. Each transmitter would be in a bunker hardened against bombs and other attacks. No single attack could destroy all of the transmitters, so the officials in the command center would remain in communication at all times. WiMAX system consists of two parts:
A.WiMAX Base Station or WiMAX Tower
Typically, a base station can cover up to 10 km radius. It is similar in concept of a cell-phone tower. A single MAX tower can provide coverage to very large areas big as 3,000 square miles (~8,000 square km).[4] It can also connect to another WiMAX tower using a line-of-sight, microwave link. This connection to a second tower (often referred to as a backhaul), along with the ability of a single tower to cover up to 3,000 square miles, is what allows WiMAX to provide coverage to remote rural areas.[1]
B. WiMAX receiver
The receiver and antenna could be a small box or PCMCIA card, or they could be built into a laptop the ay WiFi access is today. WiMAX could also Boost Government Security. In an emergency, communication is crucial, for government officials as they try to determine the cause of the problem, find out who may be injured and coordinate rescue efforts or cleanup operations. A gas-line explosion or terrorist attack could sever the cables that connect leaders and officials with their vital information networks. Several base stations can be connected with one another by backhaul microwave links.
· Wire line backhauling
· Microwave Point-to-Point connection
Fig 7 WiMAX Operation
8. MULTIPLE ANTENNA TECHNIQUE IN SYSTEM DESIGN