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IEEE 802.16e/Mobile WiMAX

IEEE 802.16e/Mobile WiMAX. Moise Effo. IEEE 802.16 Overview. IEEE 802.16e Protocol Stack. Network architecture. PHYSICAL Layer Description.

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IEEE 802.16e/Mobile WiMAX

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  1. IEEE 802.16e/Mobile WiMAX MoiseEffo

  2. IEEE 802.16 Overview

  3. IEEE 802.16e Protocol Stack

  4. Network architecture

  5. PHYSICAL Layer Description • The Mobile Wimax adopts Orthogonal Frequency Division Multiple Access (OFDMA) for improved multi-path performance in non-line-of-sight environments by: • Multiplexing operation of data streams from multiple users • Dynamically assign a subset of sub-channels to individual users. • Scalable OFDMA (SOFDMA) is introduced in the IEEE 802.16e an amendment to support scalable channel bandwidths from 1.25 to 20 MHz. • Scalability is supported by adjusting the FFT size while fixing the sub-carrier frequency spacing at 10.94 kHz.

  6. PHYSICAL Layer Description • Since the resource unit sub-carrier bandwidth and symbol duration is fixed, the impact to higher layers is minimal when scaling the bandwidth. • 802.16e systems offer scalability in both radio access technology and network architecture, thus providing a great deal of flexibility in network deployment options and service offerings. • 802.16e supports TDD and Full and Half-Duplex FDD operation.

  7. PHYSICAL Layer Description • Adaptive modulation and coding (AMC) is the matching of the modulation, coding and  signal strength and protocol parameters to the conditions on the radio link. • Hybrid Automatic Repeat Request (HARQ) is a combination of high-rate forward error-correcting coding (FEC), and ARQ (Automatic Repeat-reQuest) error-control for detectable-but-uncorrectable errors. • Fast Channel Feedback (CQICH) is a method of communicating feedback information between a mobile station and a base station by determining a need to request bandwidth allocation.

  8. MAC Layer Description Quality of service (QoS) is provided via service flows. This is a unidirectional flow of packets that is provided with a particular set of QoS parameters

  9. MAC Layer Description • Scheduling service is designed to efficiently deliver broadband data services including voice, data, and video over time-varying broadband wireless channel. The MAC scheduling service has the following properties that enable the broadband data service: • Fast Data Scheduler • Scheduling for both DL and UL • Dynamic Resource Allocation • QoS Oriented • Frequency Selective Scheduling

  10. MAC Layer Description • Mobility management • Power management Mobile Wimax supports the two modes for power efficient operation: • - Sleep Mode • - Idle Mode • Handoff there are handoffs methods supported by the mobile Wimax: • - Hard Handoff (HHO) • - Fast Base Station Switching (FBSS) • - Macro Diversity Handover (MDHO)

  11. MAC Layer Description • Security • Key Management Protocol for Traffic Encryption Control, Handoff Key Exchange and Multicast/Broadcast security messages. • Device/User Authentication by providing support for credential that are SIM-based. • Traffic Encryption, a cipher is used for the protection all the user data over the Mobil Wimax MAC interface. (AES-CCM) • Control Message Protection using AES Based CMAC. • Fast Handover Support there is a 3-way Handshake scheme to optimize the re-authentication mechanisms for fast handovers.

  12. Advanced features of mobile wimax • Smart antenna technologies: • typically involve complex vector or matrix operations on signals due to multiple antennas. OFDMA allows smart antenna operations to be performed on vector-flat sub-carriers. Complex equalizers are not required to compensate for frequency selective fading. • Mobile Wimax supports a full range of smart antenna technologies to enhance system performance. • Beamformingfor a better coverage and capacity of the system and reduce outage probability. • Space-Time Code(STC) transmit diversity codes are used to provide spatial diversity and reduce fade margin.

  13. Advanced features of mobile wimax • Smart antenna technologies • Spatial Multiplexing(SM) is to take advantage of higher peak rates and increases throughput. • multiple streams are transmitted over multiple antennas • both receiver and transmitter must have multiple antennas to achieve higher throughput. The inclusion of MIMO antenna techniques along with flexible sub-channelization schemes, Advanced Coding and Modulation all enable the802.16e technology to support a high data rate: •peak DL data rates up to 63 Mbps per sector and •peak UL data rates up to 28 Mbps per sector in a 10 MHz channel.

  14. Advanced features of mobile wimax • Fractional Frequency reuse • All cells/sectors operate on the same frequency channel to maximize spectral efficiency. • Users operate on sub-channels, which only occupy a small fraction of the whole channel bandwidth • The flexible sub-channel reuse is facilitated by sub-channel segmentation and permutation zone

  15. Advanced features of mobile wimax • Multicast and Broadcast Service (MBS) • combines the best features of DVB-H, MediaFLO and 3GPP • E-UTRA and satisfies the following requirements: • High data rate and coverage using a Single Frequency Network (SFN) • Flexible allocation of radio resources • Low MS power consumption • Support of data-casting in addition to audio and video streams • Low channel switching time

  16. Key advantages of Mobile WIMAX • Tolerance to Multipath and Self-Interference • Scalable Channel Bandwidth • Orthogonal Uplink Multiple Access • Support for Spectrally-Efficient TDD • Frequency-Selective Scheduling • Fractional Frequency Reuse • Fine Quality of Service (QoS) • Advanced Antenna Technology

  17. summarize Mobile Wimax can be considered as a real competitor for 3G for example in IP-traffic(VoIP/ IPTV). Mobile Wimax supports seamless handoff which provides switching between base stations in vehicular speeds. Mobile Wimax uses Scalable OFDMA multiplexing which maximizes the spectral efficiency.

  18. IEEE 802.16e/Mobile WiMAX Questions

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