Proposal for 15'4a altphy

1
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
Project IEEE P802.15 Working Group for Wireless
Personal Area Networks (WPANs) Submission Title
WAVEFORM MODULATED LOW RATE UWB SYSTEM -
Proposal for 15.4a alt PHY Date Submitted
Mar., 2005 Source Soo-Young Chang Company
California State University, Sacramento Address
6000 J Street, Dept. EEE, Sacramento, CA
95819-6019 Voice916 278 6568, FAX 916 278
7215, E-Mailsychang_at_ecs.csus.edu Re This
submission is in response to the IEEE P802.15.4a
Alternate PHY Call for Proposal
Abstract This document describes the
waveform modulated UWB proposal for IEEE 802.15
TG4a. Purpose For discussion by IEEE 802.15
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.
Soo-Young Chang, CSUS
Slide 1
Submission
2
WAVE FORM MODULATED LOW RATE UWB SYSTEM-
Proposal for 15.4a alt PHY-
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Soo-Young Chang
• California State University, Sacramento

Soo-Young Chang, CSUS
Slide 2
Submission
3
INTRODUCTION
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
Soo-Young Chang, CSUS
Slide 3
Submission
4
INTRODUCTION
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Use short duration impulses purely processed in
  time domain, not in frequency domain
• Simple concept only a few components in TX and
  RX
• Simple digital processing ? Low complexity ? Low
  cost
• No components for processing frequency
  information (e.g. filter, osc., etc.)
• High locating accuracy and fast ranging with very
  short duration pulses
• Stealth mode of operation possible with
  relatively small RF signature by coding frequency
  subbands with orthogonal waveforms andcodes
• Excellent co-existence capability due to adaptive
  frequency band usage flexible to eliminate
  forbidden bands (e.g. UNII band)

Soo-Young Chang, CSUS
Slide 4
Submission
5
PHY TASKS (1)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• 802.15.4 PAR Purpose
• To provide a standard for ultra low complexity,
  ultra low cost, ultra low power consumption and
  low data rate wireless connectivity among
  inexpensive devices. The raw data rate will be
  high enough (maximum of 200kbs) to satisfy a set
  of simple needs such as interactive toys, but
  scaleable down to the needs of sensor and
  automation needs (10kbps or below) for wireless
  communications.
• 802.15.4a PAR -- Purpose
• To provide a standard for a low complexity, low
  cost, low power consumption alternate PHY for
  802.15.4 (comparable to the goals for 802.15.4).
  The precision ranging capability will be accurate
  enough, several centimeters or more, and the
  range, robustness and mobility improved enough,
  to satisfy an evolutionary set of industrial and
  consumer needs for WPAN communications. The
  project will address the requirements to support
  sensor, control, logistic and peripheral networks
  in multiple compliant co-located systems and also
  coexistence (18b).
• 802.15.4 PAR Scope
• This project will define the PHY and MAC
  specifications for low data rate wireless
  connectivity with fixed, portable and moving
  devices with no battery or very limited battery
  consumption requirements typically operating in
  the Personal Operating Space (POS) of 10 meters
• 802.15.4a PAR Scope
• This project will define an alternative PHY
  clause for a data communication standard with
  precision ranging, extended range, enhanced
  robustness and mobility amendment to standard
  802.15.4 (18a).

Soo-Young Chang, CSUS
Slide 5
Submission
6
PHY TASKS (2)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Specified in existing15.4 standard
• Activation and deactivation of the radio
  transceiver
• ED within the current channel
• LQI for received packets
• CCA for CSMA-CA
• Channel frequency selection
• Data transmission and reception
• Range
• typical indoor range may be 10 to 30 m
• maximum outdoor range may be several km !!!
• ED energy detection
• LQI link quality indication
• CCA clear channel assessment

Soo-Young Chang, CSUS
Slide 6
Submission
7
PLAUSIBLE MYTHS
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Myth 1
• Low rate needs less power consumption.
• With high rates, low power consumption can be
  achieved.
• Key issue is the amount of information delivered
  and power consumption is mainly related to
  transmission time and processing time.
• Myth 2
• Digital implementation needs more complexity and
  is not easily realizable with the state-of-the
  art technologies.
• Digital implementation can be realized with less
  complexity and simple hardware and provide full
  flexibility and adaptivity.
• As the processing power increases and
  technologies advances, full digital processing is
  the trend.
• Myth 3
• Higher frequency is not easy to manage or
  implement.
• ? Unless high power is not considered, digital
  processing method can be applied for higher
  frequency band without using power amplifiers.
• Myth 4
• Since this technology was not realizable
  yesterday, today also it is not easy to realize.
• Since technologies advances rapidly, more
  sophisticated and conceptual ideas should be
  realized in the near future and considered for
  future applications.
• Moores law says that processing power increases
  double every 18 months cost amd complexity can
  be decreased with the same rate.

Soo-Young Chang, CSUS
Slide 7
Submission
8
CONSIDERATIONS FOR LOW RATE UWB (1)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Frequency band
• Enjoy full frequency band assigned 3.1 10.6
  GHz in the US
• Only max power spectral density is limited
  Transmitted power is proportional to the
  bandwidth more bandwidth means more transmitted
  power
• Pulse width is inversely proportional to
  bandwidth more accurate ranging possible for
  time based ranging
• Large bandwidth entails low fading
• High rate sampling is needed to process higher
  frequency signal using digital methods
• To overcome this problem, new processing method
  should be devised
• Transmit power
• Enjoy full power transmitted under frequency mask
  if waveforms have the spectrum similar to
  frequency mask
• Max power will be -41.3dBm/MHz7500MHz -2.54dBm
  0.5mW
• More transmit power needs more power consumption
  ??? power consumption is mainly related to
  processing time
• ? New waveform is needed to fit exactly to
  frequency mask

Soo-Young Chang, CSUS
Slide 8
Submission
9
CONSIDERATIONS FOR LOW RATE UWB (2)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Data rate
• In the technical requirements, low rate is
  suggested with expectation to reduce power
  consumption and complexity/cost
• Power consumption is mainly proportional to the
  time duration of signal transmission and
  processing
• No need to reduce data rates if higher rates
  possible with almost the same cost/efforts
• With higher data rates, less probability of
  conflict with other transmissions for random
  multiple access methods like CSMA and higher
  success rate with acknowledgements
• More pulses may be transmitted for the same
  information with higher rates higher robustness
  and more redundancy can be achieved more
  flexibility can be provided
• The amount of information delivered is the key
  issue for any communication systems
• The higher the data rate is, the less time it
  takes to deliver.
• ? More sophisticated signal processing for higher
  rates and lower cost is inevitable.

Soo-Young Chang, CSUS
Slide 9
Submission
10
CONSIDERATIONS FOR LOW RATE UWB (3)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Full digital processing
• Provide full flexibility for any change in signal
  environments, system concepts and requirements
• A variety of complex digital modulation schemes
  and any complicated system concepts can be
  accommodated
• Eliminate the cost and complexity of a down
  conversion stage at receiver without using
  oscillators (or crystals)
• Sophisticated digital signal processing
  technologies needed including high speed ADCs and
  DACs with sampling rate gt 1 Gsamples/sec
• Need to devise new signal processing
  implementations which may need new technology

Soo-Young Chang, CSUS
Slide 10
Submission
11
SYSTEM DESCRIPTION
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
Soo-Young Chang, CSUS
Slide 11
Submission
12
KEY CONSIDERATIONS
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Modulation
• Source coding
• Channel coding (FEC)
• ARQ not considered
• Interleaving
• Pulse generation
• Antenna
• Multiple access

• Synchronization
• LNA
• accommodate ultra wideband
• Message relaying
• Simultaneously operated piconets (SOP)
• Localization function
• Transmit only device
• Detection

Soo-Young Chang, CSUS
Slide 12
Submission
13
FREQUENCY PLAN
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Flexible enough to satisfy any frequency mask and
  to avoid any forbidden bands
• ? pulse waveforms can be adaptively tailored to
  any frequency mask applied with any forbidden
  bands
• With FCC mask, 3.1GHz to 10.6 GHz full frequency
  band can be used to enjoy more transmitted power
• ? 3.8 dB more power used than Gaussian pulses
  case with the same frequency band
• ? 3.8 dB more margin for link budget

Soo-Young Chang, CSUS
Slide 13
Submission
14
FREQUENCY SUBBANDS
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Whole frequency band under FCC mask is divided
  into 4 groups
• Each group has 4 subbands
• BW of a subband (10.6-3.1) GHz /16 469 MHz
• Each subband has its own waveform base waveform

group 1
group 2
group 3
group 4
f
3.1 GHz
10.6 GHz
subband 1
subband 2
subband 3
subband 4
f
w21
w22
w23
w24
base waveform
If some bands should be abandoned, this subbamd
should be a little bit smaller for example the
case that UNII band is excluded.
Soo-Young Chang, CSUS
Slide 14
Submission
15
PULSE WAVEFORM
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
Soo-Young Chang, CSUS
Slide 15
Submission
16
PULSE WAVEFORM OF SUBBAND
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Pulse waveform shape
• Mathematical derivation/expression
• Shape duration 9 ns
• Spectrum almost flat throughout the whole band
• How can pulses be generated
• Digital way? ?Overlapped with various delays
• ? can be generated with relatively lower
  sampling rate DACs
• 90 samples/waveform
• 16 waveforms/group for binary representation
• 81 waveforms/group for ternary representation
• 1440 or 7290 sample information stored in ROM per
  group
• ? 1.44 or 7.29 Kbytes ROM needed to store
  waveform information if 8 bits/sample is adopted
• Generate waveforms using DACs which have a
  sampling rate of 1 Gsamples/sec
• Analog way?
• No idea
• 4 digital ways considered in this proposal
• How can delay devices for TX and RX be
  implemented?
• ? Cost/accuracy/step size are the key issues

Soo-Young Chang, CSUS
Slide 16
Submission
17
TYPICAL PULSE WAVEFORM (BASE WAVEFORM)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• The above base waveform for bandwidth of 3.8 GHz,
  20 samples/ns
• For each subband, there is one waveform which has
  flat spectrum almost throughout the subbnad as
  shown in the above.
• Group i has four base waveforms wi1, wi2 , wi3 ,
  and wi4
• Group i has 16 waveforms mi1, mi2, mi3, . . . ,
  mi16
• mij,a wi1 b wi2 c wi3 d wi4
• where a, b, c, and d are determined by modulation
  method applied

Soo-Young Chang, CSUS
Slide 17
Submission
18
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
TYPICAL PULSE WAVEFORM (BASE WAVEFORM)

• The above base waveform for bandwidth of 0.469
  GHz, 10 samples/ns
• For each subband, there is one waveform which has
  flat spectrum as shown in the above.
• Group i has four base waveforms wi1, wi2 , wi3 ,
  and wi4
• Group i has 16 waveforms mi1, mi2, mi3, . . . ,
  mi16
• mij,a wi1 b wi2 c wi3 d wi4
• where a, b, c, and d are determined by modulation
  method applied

Soo-Young Chang, CSUS
Slide 18
Submission
19
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
SPECTRAL FLATNESS vs NO OF SAMPLES/WAVEFORM

• With the same waveform, spectral flatness depends
  on the number of samples for each waveform
• More samples makes the spectrum flatter flatter
  inside the band and more suppression outside the
  band
• Power ratiopower with perfectly flat spectrum /
  power with less perfectly flat spectrum
• For the cases
• Bandwidth 469 MHz
• Pulse width 9 ns
• No. bits/sample 8
• No. samples/waveform 50, 90, 140, 180, 280, 400

Flatness vs no of samples for Subband 1, group 1
Soo-Young Chang, CSUS
Slide 19
Submission
20
BASE WAVEFORMS FOR ONE GROUP
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• For four subbands assuming each subband has 1
  GHz BW
• If smaller BW, larger pulse width

t (ns)
0
4
Soo-Young Chang, CSUS
Slide 20
Submission
21
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
BASE WAVEFORMS FOR ONE GROUP

• For four subbands - for smaller BW, larger pulse
  width
• For BW of a subbnad in Group 1469 MHz

subband 1
subband 2
subband 3
subband 4
Soo-Young Chang, CSUS
Slide 21
Submission
22
ORTHOGONALITY OF WAVEFORMS
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• For each subband, one base waveform exists
• 16 base waveforms throughout whole band (four
  groups)
• w11(t), w12(t), w13(t), w14(t), w21(t), . . . .
  , w43(t), w44(t)
• Each waveform is almost orthogonal to each other
  or perfectly orthogonal after de-emphasis at RX
• Each group has
• 16 waveforms for binary base waveform modulation
  (OOK or BPSK) or
• 81 waveforms for ternary base waveform modulation
  (OOKBPSK)
• These waveforms are orthogonal to each other
  after de-emphasis at RX
• m1,10, m1,2 w1, m1,3 w2, . . . . , m4,16 w13
  w14 w15 w16 with OOK
• m1,1 -w1 - w2 w3 w4, . . . . , m4,16 w13
  w14 w15 w16 with BPSK

Soo-Young Chang, CSUS
Slide 22
Submission
23
CORRELATIONS BETWEEN WAVEFORMS
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Correlation
• where kth sample of ith base waveform
  of a group for N samples/waveform
• Ratio of correlations autocorrel/crosscorrel
  for various N values
• Orthogonality holds for sinusoidal waveforms with
  some conditions (Orthogonality condition, refer
  to next slide), but the waveforms used here are
  not sinusoidal with some envelope
• At receiver, de-emphasis can be used to make pure
  sinusoidal for a period
• mijmij(a wi1 b wi2 c wi3 d wi4 )(a wi1
  b wi2 c wi3 d wi4) where mij is the
  waveform transmitted and mij is the waveform
  generated at RX after de-emphasis
• After integration for a one waveform duration,
  only autocorrelation terms remain
• Orthogonality can hold at RX during detection for
  matched waveforms
• What is the best sampling frequency such that
  orthogonality can be achievable?
• Less than 8 bits/sample will be enough for
  orthogonality evaluation? need to verify
• Power consumption of ADCs goes up exponentially
  with resolution, EE times, Jan 17, 2005, pp 49

Soo-Young Chang, CSUS
Slide 23
Submission
24
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
ORTHOGONALITY OF SINUSOIDS

• A key property of sinusids is that they are
  orthogonal at different frequencies. That is,
• This is true whether they are complex or real,
  and whatever amplitude and phase they may have.
  All that matters is that the frequencies be
  different. Note, however, that the sinusoidal
  durations must be infinity.
• For length N sampled sinusoidal signal segments
  exact orthogonality holds only for the hamonics
  of the sampling rate-divided-by-N , i.e., only
  for the frequencies
• These are the only frequencies that have a whole
  number of periods in samples
• Ex. N100 for 4 ns pulse duration, fs25 GHz
• fkk25109/1002.5108k0.25k GHz
• For any integer k, fk can be determined ? center
  frequencies of each subband can be determined
• http//ccrma.stanford.edu/jos/r320/Orthogonality_
  Sinusoids.html

Soo-Young Chang, CSUS
Slide 24
Submission
25
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
CORRELATIONS BETWEEN TWO BASE WAVEFORMS

• of samples 180 of samples 90
• Correlation ratio autocorrelation/crosscorrelati
  on

Soo-Young Chang, CSUS
Slide 25
Submission
26
MODULATION
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
Soo-Young Chang, CSUS
Slide 26
Submission
27
POSSIBLE MODULATIONSFOR EACH WAVEFORM
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Each waveform can be modulated by using the
  following modulation schemes depending on
  required data rates, system complexity, detection
  method, etc

Soo-Young Chang, CSUS
Slide 27
Submission
28
MODULATION/MULTIPLE ACCESS (MA) EFFICIENCY
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Energy or power efficient? joule/sec
• Energypowertime
• Power limited by FCC mask
• Pmax-41.3dBm/MHz7500MHz-2.54dBm0.5mW
• ? to use more energy, more time needed to be
  transmitted ? totally related to transmit time
• for UWB, BWgt500MHz or fractional BWgt20 of fc ?
  short duration pulses
• one possibility to increase energy by using
  multiple pulses for one bit (or symbol)
• need to use more power under frequency mask to
  have higher power
• power constrained with frequency mask for
  LR-WPAN case
• new waveform needed to fit the frequency mask to
  have more transmitted power
• Spectrally efficient? bit/Hz
• Not important for UWB because of plenty of
  bandwidth
• Time efficient? bit/sec
• For higher rate, more important but for lower
  rate, less important ? more room for flexibility
  for LR-WPAN
• However, as bit duration increases, more power
  consumption may be required

Soo-Young Chang, CSUS
Slide 28
Submission
29
NO OF COMBINATIONS (BINARY MOD)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• For each subband, one base waveform exists
• 16 base waveforms throughout whole band
• w11(t), w12(t), w13(t), w14(t), w21(t), . . . .
  , w43(t), w44(t)
• Each waveform is almost orthogonal to each other
• For one symbol duration
• 16 waveforms per group Each group has 16
  waveforms
• m1,10, m1,2 w1, m1,3 w2, . . . . , m4,16 w13
  w14 w15 w16 for OOK
• m1,1 -w1- w2- w3- w4, . . . . . , m4,16 w13
  w14 w15 w16 for BPSK
• ?16 symbols in frequency domain because of 16
  frequency bins
• For n durations in time domain
• ? to provide MA FEC
• 16n, 8n, 4n, 2n, and 1n symbols
• n can be specified for each type of
  devices/communications/applications

Soo-Young Chang, CSUS
Slide 29
Submission
30
WAVEFORMS FOR EACH GROUP(BINARY MOD)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
group 1
group 2
group 3
group 4
f
3.1 GHz
10.6 GHz
m1,1(t)
m1,1(t)
m1,1(t)
m1,1(t)
m1,1(t)
m1,1(t)
m1,1(t)
m2,1(t)
m1,1(t)
m1,1(t)
m1,1(t)
m3,1(t)
m4,1(t)
m1,2(t)
m1,2(t)
m1,2(t)
m1,2(t)
m1,2(t)
m1,2(t)
m1,2(t)
m2,2(t)
m1,2(t)
m1,2(t)
m1,2(t)
m3,2(t)
m4,2(t)
m1,16(t)
m1,16(t)
m1,16(t)
m1,16(t)
m1,16(t)
m1,16(t)
m1,16(t)
m2,16(t)
m1,16(t)
m1,16(t)
m1,16(t)
m3,16(t)
m4,16(t)
Soo-Young Chang, CSUS
Slide 30
Submission
31
SUBGROUPS FOR EACH GROUP(BINARY MOD)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
group 1
group 2
group 3
group 4
f
3.1 GHz
10.6 GHz
SG1
SG2
SG3
SG4
Soo-Young Chang, CSUS
Slide 31
Submission
32
MODULATION PROPOSED (1)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• 4 waveforms of a subgroup are mapped to 2 bit
  (quaternary) information
• ex) m1,1(t) ? 00 m1,6(t) ? 01 m1,11(t) ?
  10 m1,16(t) ? 11
• Each user sends information using one subgroup of
  each group
• ? in one time duration 8 bit information is
  delivered for whole band
• Each waveform is modulated by OOK (1,0)

Soo-Young Chang, CSUS
Slide 32
Submission
33
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
EXAMPLES OF WAVEFORMS (OOK)

• m1,1(t) m1,5(t)
  m1,15(t)

Soo-Young Chang, CSUS
Slide 33
Submission
34
MODULATION PROPOSED (2)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• 4 waveforms of a subgroup are mapped to 2 bit
  (quaternary) information
• ex) m1,1(t) ? 00 m1,6(t) ? 01 m1,11(t) ?
  10 m1,16(t) ? 11
• Each user sends information using one subgroup of
  each group
• ? in one time duration 8 bit information is
  delivered for whole band
• Each waveform is modulated by BPSK (1, -1)

Soo-Young Chang, CSUS
Slide 34
Submission
35
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
EXAMPLES OF WAVEFORMS (BPSK)
m1,1(t) m1,11(t)
m1,16(t)
Soo-Young Chang, CSUS
Slide 35
Submission
36
MODULATION PROPOSED (3)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• 16 waveforms of a group are mapped to 4 bit
  information
• ex) mi,1(t) ? 0000 mi,6(t) ? 0101 mi,11(t)
  ? 1010 mi,16(t) ? 1111
• Each user send information using one group
• ? in one time duration 4 bit information is
  delivered
• Each waveform is modulated by OOK (1,0)

Soo-Young Chang, CSUS
Slide 36
Submission
37
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
WAVEFORM FOR DATA STREAM (OOK) FOR MODULATION
PROPOSED (3)

Soo-Young Chang, CSUS
Slide 37
Submission
38
NO OF COMBINATIONS (TERNARY MOD)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• For each subband, one base waveform exists
• 16 base waveforms throughout whole band
• w11(t), w12(t), w13(t), w14(t), w21(t), . . . .
  , w43(t), w44(t)
• Each waveform is almost orthogonal to each other
• For one symbol duration
• 81 waveforms per group 64 waveforms selected out
  of 81 waveforms per group
• m1,10, m1,2 w1, m1,3 w2, . . . . , m4,16 w13
  w14 w15 w16 for OOK
• m1,1 -w1- w2- w3- w4, . . . . , m4,16 w13
  w14 w15 w16 for BPSK
• ? 16 symbols in frequency domain because of 16
  frequency bins
• For n durations in time domain
• ? to provide MA FEC
• 64n , 32n , 16n, 8n, 4n, 2n, and 1n
  symbols
• n can be specified for each type of
  devices/communications/applications

Soo-Young Chang, CSUS
Slide 38
Submission
39
WAVEFORMS FOR EACH GROUP(TERNARY MOD)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
group 1
group 2
group 3
group 4
f
3.1 GHz
10.6 GHz
m1,1(t)
m1,1(t)
m1,1(t)
m1,1(t)
m1,1(t)
m1,1(t)
m1,1(t)
m2,1(t)
m1,1(t)
m1,1(t)
m1,1(t)
m3,1(t)
m4,1(t)
m1,2(t)
m1,2(t)
m1,2(t)
m1,2(t)
m1,2(t)
m1,2(t)
m1,2(t)
m2,2(t)
m1,2(t)
m1,2(t)
m1,2(t)
m3,2(t)
m4,2(t)
m1,64(t)
m2,64(t)
m3,64(t)
m4,64(t)
Soo-Young Chang, CSUS
Slide 39
Submission
40
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
DATA RATES WITH 100 OVERHEAD

• 1 Mbps max with 100 overhead ? Tb 1/(2 Mbps)
  500 ns
• Pulse width 9 ns ? Duty cycle lt 2

500 ns
500 ns
Soo-Young Chang, CSUS
Slide 40
Submission
41
MULTIPLE ACCESS (MA)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
Soo-Young Chang, CSUS
Slide 41
Submission
42
MULTIPLE ACCESS (MA)
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Possible MAs considered
• Frequency hopping (FH) among subbands/groups
• Not efficient because of uncertainty of FCCs
  ruling on FH so far and less usage of power
• TDMA
• Less time efficient
• More difficult to synchronize
• Direct-sequence (DS) CDMA
• Less time efficient and more complex to process
• New MA needed?

f
Group 4
Group 3
Group 2
Group 1
t4
t2
t3
t1
t5
t
16 frequency bins time domain bins
Soo-Young Chang, CSUS
Slide 42
Submission
43
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
MULTIPLE ACCESS (A)

• An orthogonal set of 8 8-bit Walsh codes is used
• Max autocorrelation, min (or zero)
  crosscorrelation each other
• One code consists of 8 frequency domain bins
• Minimal Hamming distance of this code set is 4
• One frequency bin error can be corrected while
  three bin errors can be detected works as an ECC
  code increases robustness
• 8 SOPs case
• For one user, one code is assigned
• One time domain bin is occupied by two codes
• Each code represents one bit one time domain bin
  represents two bits during one time domain bin
  two bits are delivered
• Hamming distances between two piconets codes is
  4.
• For each frequency bin waveform, BPSK is applied

Soo-Young Chang, CSUS
Slide 43
Submission
44
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
MULTIPLE ACCESS (B)

• An orthogonal set of 8 8-bit Walsh codes is used
• Max autocorrelation, min (or zero)
  crosscorrelation each other
• One code consists of 8 frequency domain bins
• Minimal Hamming distance of this code set is 4
• One frequency bin error can be corrected while
  three bin errors can be detected works as an ECC
  code increases robustness
• 64 SOPs case
• For one user, two Walsh codes (16 bits) are
  assigned
• One time domain bin is occupied by two codes
• two codes represent one bit one time domain bin
  represents one bit one time domain bit deliver
  one bit
• Hamming distances between two piconets codes are
  4 and 8.
• For each frequency bin waveform, BPSK is applied

Soo-Young Chang, CSUS
Slide 44
Submission
45
MAPPING FREQUENCY BINS TO WALSH ENCODED SYMBOLS
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
Soo-Young Chang, CSUS
Slide 45
Submission
46
IMPLEMENTATION
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
Soo-Young Chang, CSUS
Slide 46
Submission
47
TRANSMITTER STRUCTURE
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Simple structure with impulse radio concept
• FEC encoder
• Interleaver
• Pulse generator
• Modulator
• Antenna

antenna
This part can be realized using digital processing
Data in
Data manipulator
modulator
Source coding Channel coding interleaving
Pulse generator
Soo-Young Chang, CSUS
Slide 47
Submission
48
TRANSMITTER BLOCK DIAGRAM
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
data manipulator
S/P converter
input data
encoding interleaving encryption
ROM, group 1
DAC
waveform transformer

• ROM, group 2

DAC
waveform transformer
ROM, group 3
DAC
waveform transformer
ROM, group 4
DAC
waveform transformer
Soo-Young Chang, CSUS
Slide 48
Submission
49
RECEIVER STRUCTURE
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• Simple receiver structure
• Antenna - Pulse generator
• LNA - Location processor
• Demodulator
• Data detector
• De-interleaver
• Channel decoder
• Synchronizer

location
Pulse generator
Synch Information retriever
demodulator
Data De-manipulator
Data out
detector
antenna
LNA
Soo-Young Chang, CSUS
Slide 49
Submission
50
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
RECEIVING BLOCK
received signal
correlation
pulse generator
Time correlator concept
ROM
waveform conditioner
ADC
correlator
correlation
LNA
Soo-Young Chang, CSUS
Slide 50
Submission
51
LINK BUDGET ANALYSIS
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• AWGN and 0 dBi gain at TX/RX antennas assumed.
  Fc5.73GHz

Soo-Young Chang, CSUS
Slide 51
Submission
52
CONCLUSIONS
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005
Soo-Young Chang, CSUS
Slide 52
Submission
53
WHY THIS PROPOSAL?
doc. IEEE 802.15-05-0028-03-004a
Mar. 2005

• More transmit power used under frequency mask
• More margin at least 3 dB more by using full
  power under any frequency-power constraints with
  waveforms adaptive to frequency mask
• ? Spectrally efficient / more received signal
  power
• ? More chance to intercept signals
• Very simple architecture
• Directly generated pulse waveforms using ROM
• Processing in digital methods
• No need to have analog devices (e.g., mixer, LO,
  integrator, etc)
• ? low cost / low power consumption
• High location accuracy
• Wider bandwidth for each waveforms ? narrower
  pulse width
• ? more accurate location information
• High adaptability to frequency, data rate,
  transmit power requirements
• ? high scalability in frequency, data rate,
  system configuration, waveform, etc.

Soo-Young Chang, CSUS
Slide 53
Submission