OFDM

RTT

Course

Inhouse

Price on request

Description

  • Typology

    Workshop

  • Methodology

    Inhouse

  • Duration

    2 Days

Description

To review present and likely future OFDM system options. To study OFDM theory and practical performance trade offs when realising designs in small form factor devices. To examine the processing commonalities between present OFDM systems and the implications for integration in existing mobile and fixed access platforms. To assess the practical design issues implicit in adding OFDM to existing and future cellular handsets and mobile devices. Suitable for engineers wishing to update themselves on the design and implementation issues of OFDM in cellular, wireless LAN and broadcast radio systems.

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Course programme

OFDM DESIGN AND IMPLEMENTATION

Topics

A two and a half day programme for engineers wishing to update themselves on the design and implementation issues of OFDM in cellular, wireless LAN and broadcast radio systems.

Objective

* To review present and likely future OFDM system options.
* To study OFDM theory and practical performance trade offs when realising designs in small form factor devices.
* To examine the processing commonalities between present OFDM systems and the implications for integration in existing mobile and fixed access platforms.
* To assess the practical design issues implicit in adding OFDM to existing and future cellular handsets and mobile devices.

Scope

This programme is directly relevant to design engineers and product and research team leaders working at silicon level on OFDM chip sets or at system level on mobile and/or fixed receiver and transceiver design. It is particularly relevant to engineers and product and market managers involved in defining future cellular handset design policy and/or with responsibility for strategic technology planning. Typical delegate organisations include silicon vendors, handset and base station manufacturers, OEM and ODM design houses and network engineers with an interest in future PHY and MAC evolution.

DAY 1

18.30 Registration and Welcome

19.00 - 21.00 Dinner

21.00 - 22.00
OFDM Application Review
OFDM in wireline (ADSL), OFDM in wireless, rationale for using OFDM in wireless broadcasting( DRM, DAB/DMB,DVB), rationale for using OFDM in two way radio, OFDM in WiFi, present implementation in 802.11 a and g, possible future evolution, OFDM in wide area WiFI (802.16/802.20), OFDM in UWB, spectral characteristics of the UWB waveform, OFDM in cellular, practical present performance limitations. Bit rate and symbol rate requirements in personal area, local area and wide area applications, typical delay spreads, how bit rate and symbol rate determines the OFDM multiplex, how the OFDM multiplex determines processor load and power requirements. Coding techniques (COFDM) and related performance considerations.

DAY 2

08.00 - 09.00 Breakfast

09.00 - 10.30
OFDM Theory

The Fast Fourier Transform, differentiating decimation in time (DIT) and decimation in frequency (DIF), algorithms needed, typical algorithmic complexity, characterising signals and related scaling requirements, broad band signals with uniformly distributed time domain energy, broadband signals with locally distributed time domain energy, narrow band signals with uniformly distributed time domain energy, effects of clipping and quantisation noise, spikes and false signal effects. The FFT in OFDM, what it does, how it does it.

10.30 - 11.00 Coffee

11.00 - 12.30 OFDM Silicon level implementation
Biassing and related issues with fixed point arithmetic rounding, DSP MAC structures and typical clock cycle requirements, bit reversed addressing, cache optimisation and fast floating point arithmetic, nested loop FFT's, internal versus external memory, convolution for discrete signals and finite length sequences, interpolation and decimation, fractional re-sampling, examples of present FFT implementations and related DSP overheads (clock cycles, duty cycles, power drain), possible future DSP architectures and performance optimisation opportunities.

12.30 - 13.30 Lunch

13.30 - 15.00 OFDM System level implementation
Typical peak to average amplitude in the modulated waveform, the impact of clipping on signal integrity and burst error distribution, carrier spacing and related effects of non linearity and VCO instability, constellation error and transmitter modulation accuracy, centre frequency leakage effects and problems of spectral flatness (or lack of flatness), impact of higher level modulation techniques on modulator accuracy and demodulator performance. Typical performance benchmarks in present systems, sensitivity, selectivity and stability, bit rates and bit error rates and their impact on higher level performance. Link budgets, bandwidth budgets and system gain considerations (bandwidth and coding gain versus processor overhead).

15.00 - 15.30 Tea

15.30 - 17.00 OFDM System Testing
Time domain analysis of signal timing and amplitude, transmitter turn on time, PA linearity, VCO stability, modulator timing, phase accuracy and spurii, time gated freqency domain analysis of power on/off signal bursts in time sliced systems, VCO settling time and carrier stability over temperature and time, modulation quality, error vector magnitude by sub carrier, error vector magnitude at symbol level, characterising effects of PA clipping, signal filtering and phase noise on modulation accuracy.Good design practice and related performance optimisation techniques.

19.00 - 21.00 Dinner

21.00 - 22.00 Special Interest Session
Delegates are encouraged to nominate topics of particular interest to be addressed in this session.

DAY 3

08.00 - 09.00 Breakfast

09.00 - 10.30
OFDM in Broadcast Systems

The DRM music/data/text multiplex, channel bandwidths and band plans, COFDM and sub carrier options, rate and range trade offs, speech coding, audio coding and datacasting, DAB/DMB, band plan and OFDM sub carrier options, the DMB multiplex(multi-stream encoding/decoding), present vendor offerings, typical power budgets and performance metrics, DVB, band plan, OFDM sub carrier options (2K and 8K), FFT implementation,guard intervals, coding and multi path performance, DVB-H, merits/demerits of time slicing, optional 4K mode and 5MHz channel spacing options, typical power budgets and performance metrics.

10.30 - 11.00 Coffee

11.00 - 12.30
OFDM in WiFI Systems

DIfferentiating PAN (802.15), LAN (802.11 a and g) and WAN (802.16/802.20) PHY and MAC options, typical bit rates and symbol rates, delay spreads and their impact on OFDM implementation, the 802.11 g PHY and MAC , integration of OFDM, channel coding and adaptive modulation, commonalities with 802.11 a, present practical performance constraints of a and g, EVM and constellation errors,sensitivity versus data rate, peak to average ratios (a and g compared to b), receiver dynamic range, typical frame error rates (802.11b) and packet error rates (802.11 a and g), the 802.16 PHY and MAC, signalling and coding overheads, comparisons with 802.20, case study of present vendor offerings and possible future performance optimisation opportunities.

12.30 - 13.30 Lunch

13.30 - 15.00 OFDM in UWB
The multiband UWB OFDM PHY, indoor, outdoor spectral masks, band plan and sub carrier implementation, (the OFDM multiplex), receiver and transmitter architectures, sensitivity and system gain, typical performance in multipath conditions, data rate and range trade offs, bit rates,symbol rates and modulation schemes, co existence issues of UWB with other radio systems (Bluetooth, WiFi, UMTS).

15.00 - 15.30 Tea

15.30 - 17.00
OFDM in Cellular

Practical aspects of integrating 802.11 a and b into cellular phones, power budgets and co existence with other PHYoptions (UMTS/EDGE/Bluetooth), practical aspects of integrating DRM/DAB/DMB into cellular phones, practical aspects of integrating DVB and/or DVB-H into cellular phones, practical aspects of integrating OFDM UWB into cellular phones, commonalities in the OFDM transform and how these might be exploited in future handset designs, per megabyte power budget comparisons, impact of multiple (OFDM) PHY phones on offered traffic and network functionality, possible future solutions.

17.00 Summary and Close

OFDM

Price on request