Based on the Khatri-Rao matrix product, we propose a novel unitary space-time modulation design called KR-USTM in this paper. Different from existing USTM schemes, such as the systematic approach and space-time frequency-shift keying (ST-FSK), KR-USTM does not require any computer search and can be applied to any number of transmit antennas. Moreover, the special structure of KR-USTM also makes it a high-rate scheme and achieve full antenna diversity as well as lower decoding complexity. Simulation results show that the proposed KR-USTM constellation achieves error performance comparable to existing USTM designs at low rates, while it outperforms them at high rates.

In this letter, we propose a closed-form joint space-time channel and direction of arrival (DOA) blind estimation algorithm for space-time coded MC-CDMA systems equipped with a uniform linear array (ULA) at the base station in frequency-selective fading environments. We prove that the signal subspaces defined by the receive data covariance matrix can be determinately separated into an equivalent set of signal subspaces spanned by the space-time channel vector of an individual user. From these signal subspaces, the space-time channels of multiple users are estimated using the subspace method.

The uplink of a space-time block coded multicarrier modulation code division multiple access (MC-CDMA) system equipped with a uniform linear array (ULA) at the base station is studied. A blind decoder that provides closed-form solutions of both transmitted symbol sequences and directions of arrival (DOAs) for all active users in one macrocell is derived without the uplink space-time vector channel estimation. The decoder uses an ESPRIT-like method to separate multiple co-channel users with different impinging DOAs. As a result, the DOAs of multiple users are obtained. In particular, a set of signal spaces, every one of which is spanned by the coded symbol sequences of an individual user, are also obtained. From these signal spaces, the original symbol sequences of multiple users are estimated by exploiting the special structure of space-time block coding (STBC) in combination with the finite alphabet property of transmitted symbols. Performance of the proposed scheme is evaluated by extensive computer simulations.

This letter proposes a vertical Bell Labs layered space-time (V-BLAST) coded direct-sequence code-division multiple-access (DS-CDMA) scheme in the frequency-selective fading environment and its blind channel identification algorithm. By exploiting an ESPRIT-like method and the singular value decomposition, the channels identification results are closed-form solutions. Moreover, the proposed scheme employs the precoding in the transmitter to eliminate the constraint of more receive antennas than transmit ones, required by most conventional V-BLAST codec schemes. Computer simulation results demonstrate the validity of this proposed scheme.

For the measurement of the 3D surface of micro-solderballs in IC (Integrated Circuit) manufacturing inspection, a binary grating project lenses of high MTF (Modulation Transfer Function) with tilted project plane is designed in this paper. Using a combination of lenses and a tilted optical layout both on object and image plane, the wave-front aberrations are reduced and the nonlinear image distortion is corrected with nonlinearity compensation, This optical lens allows us to project the structured light pattern to the inspected objects efficiently for clear deformed coded imaging, it could be used to online measure 3D shape of micro-solderballs with high precision and accuracy.