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Open Access Publications from the University of California

Scholarly Works (5 results)

  • Article
  • Peer Reviewed
UC Riverside Previously Published Works (2007)

For four (or more) transmitters, a new design of

differential space-time block code allowing symbol-wise decoding

is presented in this letter. The new design not only has the

minimum (symbol-wise) decoding complexity as that by Yuen,

Guan and Tjhung (YGT) but also yields a lower error rate. While

the YGT code uses a specially designed symbol constellation, the

new code uses a conventional QAM with a rotation. At a high

data rate such as 3bps/Hz, the new design with symbol-wise

decoding complexity can even yield a lower error rate than the

code by Zhu and Jafarkhani that has the pair-wise decoding

complexity

    Cover page: A New Design of Differential Space-Time Block Code Allowing Symbol-Wise Decoding
    • Article
    • Peer Reviewed
    UC Riverside Previously Published Works (2007)

    For four (or more) transmitters, a new design of differential space-time block code allowing symbol-wise decoding is presented in this letter. The new design not only has the minimum (symbol-wise) decoding complexity as that by Yuen, Guan and Tjhung (YGT) but also yields a lower error rate. While the YGT code uses a specially designed symbol constellation, the new code uses a conventional QAM with a rotation. At a high data rate such as 3bps/Hz, the new design with symbol-wise decoding complexity can even yield a lower error rate than the code by Zhu and Jafarkhani that has the pair-wise decoding complexity.

      Cover page: A new design of differential space-time block code allowing symbol-wise decoding
      • Article
      • Peer Reviewed
      UC Merced Previously Published Works (2015)
      In this paper, we consider a stochastic deployment problem, where a robotic swarm is tasked with the objective of positioning at least one robot at each of a set of pre-assigned targets while meeting a temporal deadline. Travel times and failure rates are stochastic but related, inasmuch as failure rates increase with speed. To maximize chances of success while meeting the deadline, a control strategy has therefore to balance safety and performance. Our approach is to cast the problem within the theory of constrained Markov decision processes (CMDPs), whereby we seek to compute policies that maximize the probability of successful deployment while ensuring that the expected duration of the task is bounded by a given deadline. To account for uncertainties in the problem parameters, we consider a robust formulation and we propose efficient solution algorithms, which are of independent interest. Numerical experiments confirming our theoretical results are presented and discussed.
        Cover page: Trading Safety Versus Performance: Rapid Deployment of Robotic Swarms With Robust Performance Constraints
        • Article
        • Peer Reviewed
        UC Riverside Previously Published Works (2008)
        It is shown that for four-transmitter systems, a family of four-by-four unit-rate complex quasi-orthogonal space–time block codes, where each entry equals a symbol variable up to a change of sign and/or complex conjugation, can be generated from any two independent codes via elementary operations. The two independent groups of codes in the family generally have different properties of diversity, but the codes in each group have the same diversity provided that the differential symbol constellation is symmetric. It is also shown that for four-transmitter systems, an eight-by-four unit-rate complex linear dispersion space–time block code can be constructed by using Hurwitz–Radon families of matrices of size eight such that diversity three is guaranteed even when all symbols are independently selected from any given constellation. This code is so far the only known unit-rate linear dispersion code that has diversity no less than three for four transmitters under any given constellation.
          Cover page: An insight into space–time block codes using Hurwitz–Radon families of matrices
          • Article
          • Peer Reviewed
          UC Riverside Previously Published Works (2021)
          This paper considers the secrecy performance of several schemes for multi-antenna transmission to single-antenna users with full-duplex (FD) capability against randomly distributed single-antenna eavesdroppers (EDs). These schemes and related scenarios include transmit antenna selection (TAS), transmit antenna beamforming (TAB), artificial noise (AN) from the transmitter, user selection based their distances to the transmitter, and colluding and non-colluding EDs. The locations of randomly distributed EDs and users are assumed to be distributed as Poisson Point Process (PPP). We derive closed form expressions for the secrecy outage probabilities (SOP) of all these schemes and scenarios. The derived expressions are useful to reveal the impacts of various environmental parameters and user's choices on the SOP, and hence useful for network design purposes. Examples of such numerical results are discussed.
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