CSSComparisonsandInformativePapers

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Project IEEE P802.15 Working Group for Wireless
Personal Area Networks (WPANs) Submission Title
CSS-Comparisons-and-Informative-Papers Date
Submitted 15 November 2004 Source John
Lampe Company Nanotron Technologies
GmbH Address Alt-Moabit 61, 10555 Berlin,
Germany Voice49 30 399 954 135, FAX 49
(30) 399 954 188, E-Mail J.Lampe_at_nanotron.com
Re This submission is in response to the TG4a
CFI Abstract This submission includes
comparisons of CSS to some requirements from
TG4as SCD, and CSS information. Purpose This
document provides additional background
information supporting the proposal of CSS as the
baseline PHY for TG4a Notice This document has
been prepared to assist the IEEE P802.15. It is
offered as a basis for discussion and is not
binding on the contributing individual(s) or
organization(s). The material in this document is
subject to change in form and content after
further study. The contributor(s) reserve(s) the
right to add, amend or withdraw material
contained herein. Release The contributor
acknowledges and accepts that this contribution
becomes the property of IEEE and may be made
publicly available by P802.15.
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CSS Comparisons, and Informative Papers

• presented by
• John Lampe Nanotron Technologies GmbHBerlin,
  Germany
• www.nanotron.com

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Key Properties of CSS
High robustness Due to the high BT product and
their asynchronous nature, chirp systems are very
resistant against disturbances. Multipath
resistant Due to the frequency spreading of
chirp pulses, CSS is very immune against
multipath fading CSS can even take advantage of
RF echoes.
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Key Properties of CSS
Long range Due to high system gain, as well as
noise, interference and fading resistance, CSS
has exceptional range for a given transmit power
and conditions. Location awareness CSS gives the
ability to determine the distance (range) between
two stations. Low power consumption CSS allows
the designer to choose a simple analog
implementation, which often consumes much less
power.
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Key Properties of CSS
Low PHY latency With CSS a wireless connection
can be established very quickly because
synchronizations on carrier frequency and data
clock are not required. Antenna
position Reception is possible with almost any
antenna position due to the wide bandwidth.
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Selection Criteria Document Overview

• 3.1 Unit Manufacturing Cost/Complexity (UMC)
• In the current implementations of CSS from
  Nanotron, Tx and Rx are approximately equal size.
  For 0.35 µm SiGe BiCMOS the PHY portion of the
  chips are about 8 mm2. Newer chip designs using
  CMOS are underway.
• The receiver and transmitter in a CSS system can
  tolerate significant frequency offset without
  significant loss of processing gain. 1
• 3.3 Signal Robustness
• Chirp uses time and frequency correlation to
  minimize non-desirable signals. Multipath and
  other RF is reduced by the processing gain. 2, 3

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Selection Criteria Document Overview

• 3.3.3 Coexistence
• CSSs power spectral density is lower than that
  for IEEE 802.15.4 O-QPSK for the same transmit
  power
• Low IEEE 802.15.4 duty cycle enhances coexistence
• Proposals packet duration is shorter than that
  of IEEE 802.15.4 due to the higher data rate
• Proposal will include channelization to enhance
  coexistence via FDMA
• Current Nanotron systems show low susceptibility
  to interferers -6 dB C/I

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Selection Criteria Document Overview

• 3.4 Technical Feasibility
• Nanotron has working chips in customer pilots
  additionally Nanotron has received ETSI approval
  for its CSS implementation and is pursuing US
  approval. The use of the 2.4 GHz ISM band allows
  this system to be immediately globally deployed.
• 3.5 Scalability
• Numerous scalability parameters such as channel
  bandwidth, coding method, data rate, transmit
  power levels, and pulse shape allow this system
  to be optimized to the applications

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Selection Criteria Document Overview

• 5.2 Size and Form Factor
• Small size will result from high levels of
  integration. Nanotron has demonstrated that the
  CSS system can be fully integrated on an IC using
  either SiGe or CMOS processes.
• 5.3 PHY-SAP Payload Bit Rate and Data Throughput
• Although Nanotron has demonstrated numerous data
  rates, Nanotron supports the 1 Mb/s which has
  been noted by TG4a to be a good higher data rate
  to allow better coexistance and lower energy
  consumption.

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Selection Criteria Document Overview

• 5.4 Simultaneously Operating Piconets (SOP)
• There are numerous methods to achieve
  simultaneity most significant are channelization
  (FDMA) and modulation/coding (CDMA). Nanotron
  will propose multiple channels to allow SOP in
  addition to its ability to use modulation/coding.
• 5.5 Signal Acquisition
• Short signal acquisition time is a strength of
  this proposal. Signals will be acquired within
  the preamble (less than 32 µS) and will
  automatically track from then on.

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Selection Criteria Document Overview

• 5.6 System Performance
• Another of CSSs strengths is system performance
  it has demonstrated superior performance in
  multipath and interfering environments 3
• 5.7 Ranging
• Chirp modulation has been used in radars for many
  years, so the ranging aspects of chirps are very
  well understood and documented. Nanotron is
  confident that CSS will provide accuracy better
  than the 1 meter specified in the TRD.

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Selection Criteria Document Overview

• 5.8 Link Budget
• The regulatory environment at 2.4 GHz allows CSS
  to be transmitted at levels from 10 to 30 dBm to
  allow for very high link margins. A link margin
  of 103 dB will result from a device with 10 dBm
  transmit power using the sensitivity specified in
  5.9. At 30 meters the link margin would be 33
  dB.
• 5.9 Sensitivity
• Nanotron has demonstrated CSS with sensitivities
  of -93 dBm at 1 Mb/s validating the theoretical
  Eb/No calculations of 9.8 dB.

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Selection Criteria Document Overview

• 5.11 Power Consumption
• Due to its low gate count and higher data rate
  the energy consumption of CSS is predicted to be
  better than the current 15.4 systems being
  deployed.
• 5.12 Antenna Practicality
• The antennas for this 2.4 GHz proposal are small
  yet efficient, easy to manufacture, and can be
  bought off the shelf as proven by the millions of
  antennas for 802.11x, 802.15.x, and Bluetooth
  devices

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Partial listing of the Public Domain Papers on
Chirp Spread Spectrum

• 1 A robust high speed indoor wireless
  communications system using chirp spread spectrum
• Pinkney, J.Q. Sesay, A.B. Nichols, S. Behin,
  R.Electrical and Computer Engineering, 1999
  IEEE Canadian Conference on  ,Volume 1 , 9-12
  May 1999
• 2 A Robust Ultra Broadband Wireless Communication
  System Using SAW Chirped Delay Lines
• A. Springer, A. Pohl, W. Gugler, M. Huemer, L.
  Reindl, C. C. W. Ruppel, F.Seifert, R. Weigel
• The feasibility of combating multipath
  interference by chirp spread spectrum techniques
  over Raleigh and Rician fading channels
• Ywh-Ren Tsai, Jin-Fu Chang
• 4 Gated Chirps for Signal Processing and
  Communication Engineering
• Alfred Pohl, Martin Brandl, Reinhard Steindl,
  Leonhard Reindl, Franz Seifert

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Partial listing of the Public Domain Papers on
Chirp Spread Spectrum

• 5 Bit Error Rate Probabilities of Chirp Spread
  Spectrum Modulation in the AWGN Channel with
  Overlap (pending publishment)
• John Pinkney, Member, IEEE, Abu Sesay, Member,
  IEEE.
• 6 A Chirp Spread Spectrum DPSK Modulator and
  Demodulator for a Time Shift Multiple Access
  Communication System by using SAW devices
• Yoshihiko Takeuchi and Kazuhiko Yamanouchi
• 7 A Chirp-Based Wideband Spread Spectrum
  Modulation Technique for WLAN Applications
• W. Gugler, A. Springer and R. Weigel
• 8 Fast Adaptive Interference Cancellation in Low
  Cost SAW Based Chirp Spread Spectrum Systems
• Alfred Pohl, Gerald Ostermayer, Leo Reindl, Franz
  Seifert, Robert Weigel