Infrared wireless communication and optical communication usually adopt on-off keying (OOK) and pulse position modulation (PPM). In [1] we presented the iterative maximum a posteriori probability (MAP) decoding of Turbo coded OOK and Turbo coded binary PPM (BPPM). In this paper, we present a soft-output Viterbi algorithm (SOVA) based iterative decoding of Turbo coded OOK and Turbo coded BPPM. W...

A hybrid pulse interval modulation – code division multiple access (PIM-CDMA) is proposed. Expression for bit error rate (BER) is given. Numerical results presented are compared with hybrid PPM-CDMA and OOK-CDMA schemes. For a low number of users PIM-CDMA achieves similar and marginally lower BER performance compared with PPM-CDMA and OOK-CDMA, respectively. For large number users it offers bet...

Sensor nodes in wireless sensor networks (WSNs) are often expected to operate on batteries for a long period of time. Battery power-ef ciency is a critical factor dictating the lifetime of WSNs. In this paper, we compare two pulse-based modulations, namely pulse position modulation (PPM) and on-off keying (OOK), both of which are suitable for WSNs due to their low complexity transceivers. The c...

This paper has presented the different advanced modulation techniques for free space optical (FSO) communication systems transmission efficiency enhancement and signal quality estimation in weak, medium and strong turbulence communication channels. The bandwidth and power efficiency issues in free space optics (FSO) transmissions are addressed under non return to zero on-off keying (NRZ-OOK), r...

DH-PIM modulation as an alternative to other pulse modulation schemes is presented. Its symbol and spectral properties are given. Expressions for slot and packet error rates are presented. Results obtained for the packet error rate are compared with OOK and PIM. It offers the same performance as PIM but considerably better performance compared with OOK.

In this paper DH-PIM modulation scheme and its properties are discussed. Expressions for, symbol length, transmission capacity, bandwidth requirements, photocurrent, power spectral density and slot and packet error rates are presented. Results obtained for the packet error rate are compared with OOK and PIM. It offers the same performance as PIM but considerably better performance compared with...

On–off keying (OOK) has repossessed much new research interest to realize green communication for establishing autonomous sensor networks. To realize ultra-low power wireless design, we investigate the minimum energy per bit required for reliable communication of using OOK in a noncoherent channel setting where envelope detection is applied at the receiver. By defining different OOK channels wi...

OBJECTIVE To review the published literature to evaluate the safety of overnight orthokeratology (OOK) for the treatment of myopia. METHODS Repeated searches of peer-reviewed literature were conducted in PubMed (limited to the English language) and the Cochrane Central Register of Controlled Trials (no language limitations) for 2005, 2006, and 2007. The searches yielded 495 citations. The pan...

We propose a bidirectional wavelength division multiplexing passive optical network (WDM-PON) based on a reflective semiconductor optical amplifier (RSOA) by employing a differential quadrature phase shift keying (DQPSK) signal for down-link and an on-off keying (OOK) re-modulated signal for up-link over 45km SMF colorless WDM-PON without dispersion compensation was demonstrated for both 10 Gbi...