This document discusses various modulation schemes used in different wireless technologies. It describes technologies like Bluetooth, Zigbee, Wi-Fi, UWB, and provides details on their modulation techniques. For Bluetooth, it explains that GFSK is used in basic rate mode while variants of GFSK and PSK are used in enhanced data rate mode. For Zigbee, it states that BPSK and OQPSK/MSK are used depending on frequency. It also discusses modulation schemes like OFDM, QAM used in Wi-Fi and their advantages. For UWB, it describes modulation techniques like PPM, PAM, OOK used.

1. Modulation Schemes used
in Wireless Technologies
Vijitaa Das
MTech, EDT
2019-2021 Batch

2. MODULATION SCHEMES

3. Wireless Technologies
- the communication or transmission of information over a distance without requiring
wires, cables or any other electrical conductors.
- by using electromagnetic waves like radio frequencies, infrared, satellite, etc.
Types of Wireless Technologies:
• BLUETOOTH
• ZIGBEE
• WI-FI
• UWB
• WiMAX
• NFC

4. BLUETOOTH
- It uses short-wavelength radio frequency based on the IEEE 802.15.1 standard to
connect several device simultaneously over a short distance.
- Enables WPAN.
- Communicate over the air at a distance of 10 meters.
- It may increase to 100 meters as well.
- Operates within the 2.4 GHz ISM frequency band.
- Integrated Devices including cell phones, computers, speakers, printers, keyboards, etc.

5. BLUETOOTH MODULATION
• It uses Frequency-hopping spread spectrum.
• It has different signal modulation techniques for each Bluetooth mode (BR,
EDR and HS).
• The Gaussian Frequency Shift Keying (GFSK) is used in the BR mode.
• π/4 DQPSK (Differential Quadrature Phase Shift Keying) and 8DPSK is used
in the EDR (Enhanced Data Rate) mode.
• These are variants of the combination of the GFSK and the PSK.

6. GFSK

7. BLUETOOTH MODULATED SIGNAL
• The modulated signal can be denoted as :
where, fc = frequency carrier,
T = bit period,
h = modulation index,
x(t) = input of the modulator
• GFSK is determined by :
- Modulation Index
- Bandwidth of Gaussian Filter
• Bluetooth-> bit rate is 1Mb/s, BT is 0.5 and modulation index varies from 0.28 to 0.35.

8. Advantages of GFSK
• It provides a better spectral efficiency compared to FSK.
• Enables the use of efficient radio power amplifiers, thereby saving
on battery life.
Disadvantages of GFSK
• It can’t provide more than 1Mbit/s.

9. BLUETOOTH EDR Mode & HS Mode

10. ZIGBEE
- It uses low-power radio frequency based on the IEEE 802.15.4 to provide low data
rate short-distance transmission for specific applications.
- Enables WPAN.
- Communicate over the air at a distance of 10 meters.
- It may increase to 100 meters as well.
- Operates within the 2.4 GHz ISM frequency band.
- Used in embedded applications such as sensors and control devices.

11. ZIGBEE MODULATION
• Uses DSSS.
• The modulation techniques varies according to the used frequencies.
• Frequency of 868 MHz --- BPSK.
• Frequency of 2405 MHz --- OQPSK or MSK.
• QPSK uses 2 carrier signals whose phases are different by 90 degree.
• Both signals, combined and transmits together in order to carry 2 bits of
data.

13. QPSK VS OQPSK

14. OQPSK

15. • The limited phase shift that must be imparted.
• The sudden phase-shifts occur about twice as often as for QPSK (since
the signals no longer change together), but they are less severe.
Advantages of OQPSK

16. Wi-Fi
- It uses radio frequency bands based on the IEEE 802.11 standard to connect client
devices over local areas.
- Enables WLAN.
- Wi-Fi routers operating on the 60GHz ISM Frequency band.
- Can reach up to 150ft-300ft (100 m) as well.
- Integrated Devices including cell phones and routers.

18. • OFDM is a form of signal format that uses a large number of close spaced carriers that
are each modulated with low rate data stream.
• When the signals are orthogonal to each other there is no mutual interference.
• The use of OFDM is a natural choice for LTE.
• This is modified to provide the multiple access scheme: OFDMA in the downlink and
SC-FDMA in the uplink.
• Within the OFDM signal, three types of modulation for the LTE signal:
QPSK (= 4-QAM)
16QAM
64QAM
• Modulation types for 802.11ay /802.11ac:
BPSK, QPSK, 16 QAM, 64 QAM, 256 QAM
OFDM

19. QAM
• It is a combination of phase modulation and amplitude modulation.

20. • The move from 256-QAM to 1024-QAM increases the number of bits
carried per OFDM symbol from 8 to 10, for a data-rate and spectral-
efficiency boost of 25%.
• This increases peak data-rates under good conditions (high SNR).
1024-QAM

21. Advantages of OFDM
• Makes efficient use of the spectrum by allowing overlap.
• By dividing the channel into narrowband flat fading sub-channels,
OFDM is more resistant to frequency selective fading than single
carrier systems are.
• Provides good protection against cochannel interference and
impulsive parasitic noise.
• Channel equalization becomes simpler than by using adaptive
equalization techniques with single carrier systems.
• Spectrum efficiency
• Resilient to ISI

22. Ultra-Wideband (UWB)
- It is a short-range, wireless communication protocol that – like Bluetooth or Wi-Fi
based on IEEE 802.15. 4 standard uses radio spectrum.
- Enables WPAN.
- Communicate over the air at a distance up to 10 m or 30 feet.
- Operates from 3.1 to 10.6 GHz ISM frequency band.
- Used in public protection, construction, engineering, science, medical,
transportation for data communication, localization and identification, and radar and
sensing applications.

23. UWB MODULATION
• Information can be coded using pulse position modulation (i.e. binary or M-ary
PPM), PAM (i.e. binary or M-ary PAM), bi-phase modulation of pulse polarity (i.e.
BPM), modulation by a doublet of a positive pulse followed by a negative pulse or
vice versa, and pulse on-off keying (OOK).
• UWB signal transmission involves pulse shaping, spreading, modulation, and
randomization.
• Appropriate hybrid modulation and randomization of a UWB signal makes its
spectrum appear like additive white Gaussian noise.
• UWB modulation impacts the power spectral density of the radiated signal and
consequently its impact on radio communication services.

24. OOK (On-Off Keying)

25. PPM (Pulse Position Modulation)

26. PPM VS OOK
• The PPM scheme allows easy implementation for UWB receiver.
• For the transmitting power, an OOK pulse can have double energy as compared to
a PPM pulse. In other words, the PPM scheme has a poorer bit-error rate (BER)
performance than the OOK scheme.
• The OOK scheme provides a higher data transmission rate than the PPM scheme.

27. REFERENCES
[1] An enhanced pulse position modulation (PPM) in ultra-wideband (UWB)
systems by Lingxiu Chen, University of Northern Iowa, 2014
[2] https://www.electronics-notes.com/articles/connectivity/4g-lte-long-term-
evolution/ofdm-ofdma-scfdma-modulation.php
[3] https://www.commscope.com/blog/2018/wi-fi-6-fundamentals-what-is-1024-
qam/
[4] https://blogs.arubanetworks.com/solutions/mobility/what-is-qam/
[5] DESIGN OF ZIGBEE TRANSCEIVER FOR IEEE 802.15.4 USING MATLAB/SIMULINK,
By RAVIKANTH KANNA, NIT, Orissa, 2011
[6] https://www.electronics-notes.com/articles/connectivity/bluetooth/radio-
interface-modulation-channels.php