The document proposes a Direct-Code Space Shift Keying (DC-SSK) modulation technique to improve the spectral efficiency of Space Shift Keying (SSK). DC-SSK exploits the indices of both active and silent antennas to transmit information, whereas SSK only uses the indices of active antennas. DC-SSK groups bits to directly determine the transmitting antennas according to the bit values. Analysis shows DC-SSK increases data rate linearly with the number of antennas and outperforms SSK in bit error rate. The results indicate DC-SSK is a promising solution to improve spectral efficiency and meet increasing data rate demands.

1. Exploiting Indices of Silent Antennas to
Increase theSpectral Efficiencyof SSK
ExploitingIndicesof SilentAntennastoIncreasetheSpectralEfficiencyofSSK 1
By
Nafel N. Alotaibi & Khairi A. Hamdi

2. Introduction
2
• Space shift keying (SSK) modulation exploits the multipath
phenomena to identify which of the transmitting antennas was
used, based on the fact that the path of every antenna signal is
unique and no other signal can pass through this way except from
the same antenna.
• In SSK and generalized SSK, the symbols are transmitted only by
the active antennas’ indices, while the inactive antennas remain
unexploited; this limits the spectral efficiency.
• To combat this limitation, we propose a direct-code for space shift
Keying (DC-SSK) modulation technique.
EXPLOITING INDICES OF SILENT ANTENNAS TO INCREASE THE SPECTRAL EFFICIENCY OF SSK

3. The Contribution
3
• We propose a Direct-Code Space Shift Keying (DC-SSK) as a new
physical layer coding scheme, to improve the spectral efficiency
by exploiting the indices of both the silent and active antennas, to
convey the information.
• In DC-SSK, the transmitter is allowed to use 0, 1, ..., N antennas for
each symbol, and groups of N bits are used to derive the
transmitting antennas directly according to the bit value, active
for ’1’ and inactive for ’0’.
• We analysed the performance of DC-SSK and validate the results
by simulation, and the results show that DC-SSK is a promising
solution to respond to the massive demand on the data rates since
it increases the data rate linearly with N.
EXPLOITING INDICES OF SILENT ANTENNAS TO INCREASE THE SPECTRAL EFFICIENCY OF SSK

4. SM
4EXPLOITING INDICES OF SILENT ANTENNAS TO INCREASE THE SPECTRAL EFFICIENCY OF SSK
DATA
Select
the antenna
Conventional
Modulation
0
1
Ex:
Data=01
Modulation= BPSK
0
1

5. From SM to SSK
5EXPLOITING INDICES OF SILENT ANTENNAS TO INCREASE THE SPECTRAL EFFICIENCY OF SSK
DATA
Select
the antenna
Conventional
Modulation
0
1
0
1

6. EXPLOITING INDICES OF SILENT ANTENNAS TO INCREASE THE SPECTRAL EFFICIENCY OF SSK 6
DC-SSK Principle
…0111010000110100 tN
…0 1 0 0 0 1 0 0
…1 1 1 0 0 1 1 0Grouping
Time slots

7. EXPLOITING INDICES OF SILENT ANTENNAS TO INCREASE THE SPECTRAL EFFICIENCY OF SSK 7
DC-SSK Example
…0111010000110100 tN
…0 1 0 0 0 1 0 0
…1 1 1 0 0 1 1 0Grouping
Time slots

8. EXPLOITING INDICES OF SILENT ANTENNAS TO INCREASE THE SPECTRAL EFFICIENCY OF SSK 8
DC-SSK Nyquest Capacity
For a noiseless channel, Nyquest Capacity formula C = 2B log2 (M)
relates the capacity with the number of signal levels (constellation
size)
𝐶𝑆𝑆𝐾 = 2 log2 𝑁𝑡
𝐶 𝐷𝐶−𝑆𝑆𝐾 = 2 log2 2 𝑁𝑡 = 𝑁𝑡

9. 9EXPLOITING INDICES OF SILENT ANTENNAS TO INCREASE THE SPECTRAL EFFICIENCY OF SSK
Performance Analysis
The final form of probability of error

10. 10EXPLOITING INDICES OF SILENT ANTENNAS TO INCREASE THE SPECTRAL EFFICIENCY OF SSK
The Bit-rate

11. 11EXPLOITING INDICES OF SILENT ANTENNAS TO INCREASE THE SPECTRAL EFFICIENCY OF SSK
Upper Bounds of DC-SSK and SSK BER

12. 12EXPLOITING INDICES OF SILENT ANTENNAS TO INCREASE THE SPECTRAL EFFICIENCY OF SSK
BER vs SNR

13. Conclusion
13
• DC-SSK is a new physical layer coding scheme to
improve the spectral efficiency of SSK modulation.
• DC-SSK increases the data rate linearly with the
number of transmitting antennas.
• The results show that DC-SSK is a promising solution
to respond to the massive demand on the data rates.
EXPLOITING INDICES OF SILENT ANTENNAS TO INCREASE THE SPECTRAL EFFICIENCY OF SSK

14. 14EXPLOITING INDICES OF SILENT ANTENNAS TO INCREASE THE SPECTRAL EFFICIENCY OF SSK