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WiMAX_Intro
1. 4G Integrated WiMAXA Detailed Introduction By BRIAN RITCHIE Twitter : brianritchie Facebook : facebook.com/brianritchie
2. Who Am I ? Co worked on the Enterprise Architecture for some of the largest regional as well as international companies Rolled out the first official OSS Centre of Excellence strategy and implementation for a local Financial Institution Experience with large scale Project Management for core systems Designed and Implemented Research and Incubation Services for large scale corporations
4. Before We Go Further !!! Case Study : How would you cope with the increased need for bandwidth delivered at lower costs to more subscribers ? Assume the technologies available to you are the following : Ethernet Wi-Fi Cell Towers, Base Stations, Data Centers, Traditional CDNs
6. What is WiMAX ? WiMAX = Worldwide Interoperability for Microwave Access Aim : To provide long distance wireless broadband for applications similar to the coverage and quality of service (QOS) of cellular networks Promotes the IEEE 802.16 standards
8. What is 802.16 ? IEEE 802.16 originally aimed to define fixed broadband wireless (FBW) May possibly replace the past wireless local loop (WLL) in telecommunications Able to deliver performance comparable to traditional cable, T1, xDSL, etc.
9. What is 802.16 ? Advantages of 802.16 include : Quick and easy deployment especially for areas that are difficult to be wired. No physical limitations compared to wired infrastructure Cost effective for $/MB of data Increased security through multi-level encryption Highly scalable with significantly higher throughout
11. Wireless Architectures There are two types of wireless deployment Point to Point (P2P) Point to Multipoint (PMP) How does Line of Sight (LOS) affect these architectures ?
12. Wireless Architectures Point to Point (P2P) Architecture P2P is used where there are two points of interest Usually used for backend communication/data transfer (e.g: data center, co-lo, base stations) or as a point for distribution for PMP Higher throughput than PMP Transmitter Receiver
13. Wireless Architectures Point to Multipoint (PMP) PMP is used primarily for distribution Able to serve hundreds of dissimilar subscribers simultaneously
14. How does it affect WiMAX ? Previous wireless technologies could not server NLOS WiMAX functions best in LOS but is also able to serve NLOS with acceptable throughput which led to lower cost per subscriber because more subscribers could be served from one base station Line of Sight (LOS) Line of Sight (LOS) Non Line of Sight (NLOS)
15. What is WiMAX ? Types of WiMAXdeployments and what its not
17. Fixed WiMAX ( IEEE 802.16d ) The capability of Fixed WiMAX One of the major limitations was that this architecture was not mobile. Users were not able to transition data between base towers P2P : LOS = 30 Miles/48km , 72Mbps PMP : NLOS = 6 Miles/9.6km , 40Mbps
18. Mobile WiMAX ( IEEE 802.16e ) The capability of Mobile WiMAX Enabled cell-phone like infrastructure on a large scale. This enabled users to move between base towers without loss of connection which allows for more mobile 0n-demand applications to be deployed
24. Advantages Advantage of Radio architecture – Radio is protected from weather extremes, this reduces interruptions/signal loss Advantage of Antenna architecture – optimizes the performance of the WMAN connection between transmitter and receiver
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26. The rule for deploying Heliax cables = shorter the better
27. Heliax cables loses 1 dB for every 10 feet of cableWiMAX Radio Heliax Cables
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29. Sector – more focused, used more widely than Omni due to better performance
32. Link Budget Link Budget – Performance of the WMAN connection Link Budget – Power received at each detector Prx = Ptx + Gtx – Apl + Grx – Am Where Prx= received power at detector (dBm) Ptx = transmitter output power (dBm) Gtx = transmitter antenna gain (dBi) Grx = receiver antenna gain (dBi) Apl = path loss (dB) Am = miscellaneous attenuation (link margin, diffraction loss, connector loss, physical object interference (eg : wall, glass, trees, etc) Transmitter Receiver
33. Frequency Plan Logic Exercise Assuming you had a limit of three different frequencies for deployment to 9 base stations, how would you do it ? NOTE : Same frequencies in close proximity will cause interruption to your subscribers. Assume frequencies are deployed by their base station using Omni directional antennas with equal range radius
34. Answer : This is also how cellular/wireless operators function with limited frequencies to cover the most surface area without interference to the user Frequency Plan
36. IEEE 802.16 Reference Model Scope of Standard CS SAP Management Entity Service Specific Convergence Sublayer MAC SAP Management Entity MAC Common Parte Sublayer MAC Network Management System Privacy Sublayer PHY SAP Management Entity PHY Layer PHY Management Plane Date/Control Plane
37. IEEE 802.16 MAC MAC = Medium Access Control Has a PMP network topology with support for mesh network topology Backhaul can either be ATM = Asynchronous Transfer Mode or packet based (eg : IP Networks)
38. IEEE 802.16 MAC Has three sub-layers in the Reference Model Service Specific Convergence Sublayer (CS) – Provides any transformation/mapping of external network data through the CS Service Access Point (CS SAP) MAC Common Part Sublayer (MAC CPS) – Classifies external network service data units (SDU) and associates these SDUs to propoer MAC Service flow and Connection Identifier (CID) Privacy (or Security) Sublayer – Supports authentication, secure key exchange and encryption
39. IEEE 802.16e Handover Arch. In order to deal with mobility for the IEEE 802.16e, the MAC Layer specifies a MAC Layer Handover procedure Handover happens in 2 possible situations: When the mobile station (MS) moves and needs (due to signal fading/interference, etc) to change the base station (BS) that it is currently connected to, in order to provide better signal quality When the mobile station can be served with higher QOS at another base station
40. IEEE 802.16e Handover Arch. Prior to handover, the network topology acquisition must be achieved in 3 steps : Network topology advertisement – A BS broadcasts info regarding the network topology which must be obtained from the backbone MS Scanning the neighboring BSs – BS can allocate time intervals for the MS to perform scans and once the BS is identified, MS may attempt to synchronize with its downlink connection and estimate quality of physical channel. Association – Optional initial ranging procedure during scanning interval with respect to one of the neighboring BSs and functions to enable MS to acquire and record ranging parameters and service availability info.
41. IEEE 802.16e Handover Arch. Handover Procedure: Cell re-selection – MS uses BS info or may request scanning interval to evaluate interest in handover Handover decision and initiation – Handover begins with a decision from MS to switch from serving BS to target BS Sync to Target BS Downlink – MS first syncs downlink transmissions from target Bs to obtain parameters. If target BS received previous handover notice from serving BS via backbone, the target BS allocates a non-contention initial range opportunity Ranging – Target BS gets info from serving BS through backbone. MS and target BS will either conduct initial ranging or handover ranging to setup correct comm parameters Termination of MS context – Terminate service at serving BS.
- Before we delve in any further into WIMAX we need to understand a little more about the 802.16 standard.
Here we can see the IEEE Project 802’S evolvement from the 802.11 WLAN to 802.16 to cope with the growing needs and demands for better bandwidth with lower cost
It is a standard
Why did it actually take off, what made people decide on this technology
Here, before we delve any further into defining and understanding WIMAX, we need to take a step back and understand the different types of Wireless architectures that are required to enable this technology
Be careful not to confuse this terms with peer to peer and/ project management professional
Can anyone tell me why P2P has a higher throughput than PMP even though PMP has more users ?
Imagine a user/police car/ambulance moving between towers and are still able to communicate via VOIP or Video
[End of slide] While this gives you a brief overview of WiMAX, we will be back to go more indepth into its network Architecture. Lets first look into its Hardware Architecure
PoE – Power over Ethernet
CPE – Customer Premise Equipment
Antenna gain relates the intensity of an antenna in a given direction to the intensity that would be produced by a hypothetical ideal antenna that radiates equally in all directions (isotropically) and has no losses.Although the gain of an antenna is directly related to its directivity, the antenna gain is a measure that takes into account the efficiency of the antenna as well as its directional capabilities. In contrast, directivity is defined as a measure that takes into account only the directional properties of the antenna and therefore it is only influenced by the antenna pattern. However, if we assumed an ideal antenna without losses then Antenna Gain will equal directivity as the antenna efficiency factor equals 1 (100% efficiency). In practice, the gain of an antenna is always less than its directivity.
