Dean Michael Thelen

MIMO radio signals over fiber in picocells for increased WLAN coverage

We show that separating base station antennas in an optically-fed 2×3 MIMO WLAN system increases the overall coverage area in picocells. A peak throughput of 130 Mb/s was measured for antenna spacings of both 16 cm and 7 m.

Data throughput tripling by Feed-Forward Equalization and photonic QPSK in a 7 Gbps single-carrier RoF link at 60 GHz

This paper investigates the use of feed-forward equalization (FFE) to combat performance limitations imposed by non-uniform channel characteristics in a wideband vector signal-modulated single-carrier radio-over-fiber (RoF) system at 60 GHz. A direct photonic QPSK modulator was implemented at 60 GHz and used in the system experiments. By combining photonic QPSK modulation and FFE, 7 Gbps data throughput was achieved over a channel bandwidth of less than 2 GHz, representing a bit-rate increase of three times over simple amplitude shift keying (ASK) modulation. The photonic QPSK modulator incorporates frequency doubling, leading to the simplification of the transmitter. In addition, frequency doubling extends the fiber length limit imposed by signal fading due to chromatic dispersion. FFE is simpler to implement and is less computation intensive than, for instance OFDM. Transmission experiments over 2 km of fiber were conducted.

Bit-rate doubling in multi-Gbps wideband ASK-modulated 60 GHz RoF links using linear feed-forward equalisation and direct conversion transceivers

Linear feed-forward equalisation is used successfully to compensate for severe electrical and optical amplitude response impairments in a 60 GHz RoF link, enabling twice the bit-rate (4.25 Gbps), through SSB operation.

Accuracy of UWB Ranging over Multimode Fiber With and Without In-Band WLAN Interference

Remote positioning of the ultra wide band (UWB) wireless technology based ranging systems using the radio over multimode fiber (RoMMF) technology is investigated here. The ranging accuracy of such a system with various fiber lengths is studied. Another aspect of the study involves the evaluation of the impact of a coexistent in-band wireless local area network (WLAN) signal (802.11a) on the accuracy of UWB ranging capabilities. The impact of a co-existent UWB signal on 802.11a WLAN performance is also evaluated using error vector magnitude (EVM) measurements.