ieee 802.16e/mobile wimax moise effo. ieee 802.16 overview

IEEE 802.16e/Mobile WiMAX

Moise Effo

IEEE 802.16 Overview

IEEE 802.16e Protocol Stack

NETWORK ARCHITECTURE

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.

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.


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.


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

Service Definition Typical Applications QoS Specifications

Unsolicited Grant Service (UGS) Real-time data streams comprising fixed-size data packets issued at periodic intervals.

T1/E1 transport, VoIP without silence suppression.

-Maximum Sustained Rate-Maximum LatencyTolerance -Jitter Tolerance

Extended Real-time Polling Service (ErtPS)

Real-time service flows that generate variable-sized data packets on a periodic basis.

VoIP with silence suppression. -Minimum Reserved Rate-Maximum Sustained Rate-Maximum LatencyTolerance-Jitter Tolerance-Traffic Priority

Real-time Polling Service (rtPS) Real-time data streams comprising variable-sized data packets that are issued at periodic intervals.

MPEG Video. -Minimum Reserved Rate-Maximum Sustained Rate-Maximum LatencyTolerance-Traffic Priority

Non-real-time Polling Service (nrtPS). Delay-tolerant data streams comprising variable-sized data packets for which minimum data rate is required.

FTP with guaranteed minimum throughout.

-Minimum Reserved Rate-Maximum Sustained Rate-Traffic Priority

Best Effort (BE) Data streams for which no minimum service level is required and therefore may be handled on a space-available basis.

HTTP. -Maximum Sustained Rate-Traffic Priority


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


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)

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.


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.

Beamforming for 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.


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.


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


Multicast and Broadcast Service (MBS)combines the best features of DVB-H, MediaFLO and 3GPPE-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

Tolerance to Multipath and Self-InterferenceScalable Channel BandwidthOrthogonal Uplink Multiple AccessSupport for Spectrally-Efficient TDDFrequency-Selective SchedulingFractional Frequency ReuseFine Quality of Service (QoS)Advanced Antenna Technology

KEY ADVANTAGES OF MOBILE WIMAX

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.

IEEE 802.16e/Mobile WiMAX

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ieee 802.16e/mobile wimax moise effo. ieee 802.16 overview

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