Zoubir A.M.,TU Darmstadt |
Koivunen V.,Wireless Excellence |
Muma M.,TU Darmstadt
IEEE Signal Processing Magazine | Year: 2012
The word robust has been used in many contexts in signal processing. Our treatment concerns statistical robustness, which deals with deviations from the distributional assumptions. Many problems encountered in engineering practice rely on the Gaussian distribution of the data, which in many situations is well justified. This enables a simple derivation of optimal estimators. Nominal optimality, however, is useless if the estimator was derived under distributional assumptions on the noise and the signal that do not hold in practice. Even slight deviations from the assumed distribution may cause the estimator's performance to drastically degrade or to completely break down. The signal processing practitioner should, therefore, ask whether the performance of the derived estimator is acceptable in situations where the distributional assumptions do not hold. Isn't it robustness that is of a major concern for engineering practice? Many areas of engineering today show that the distribution of the measurements is far from Gaussian as it contains outliers, which cause the distribution to be heavy tailed. Under such scenarios, we address single and multichannel estimation problems as well as linear univariate regression for independently and identically distributed (i.i.d.) data. A rather extensive treatment of the important and challenging case of dependent data for the signal processing practitioner is also included. For these problems, a comparative analysis of the most important robust methods is carried out by evaluating their performance theoretically, using simulations as well as real-world data. © 2012 IEEE.
Wireless Excellence | Date: 2015-02-09
The embodiments described herein provide a method and system for improve link adaption performance in wireless networks. The method for modifying the MCS index for transmission using a computed offset is provided. The offset is calculated based on HARQ feedback of transmissions. A transition probability matrix with plurality of MCS indices is used for selecting the MCS index for transmission based on the highest probability of transition. A pattern sequence of MCS indices is formed and the presence of the pattern is determined in the history of the HARQ transmissions. The frequency of the pattern presence is also determined and the MCS index is selected for the HARQ transmissions. A frequency database of MCS indices is built using source encoding techniques. The transition probabilities that are estimated from the frequency database along with a cost function associated with each MCS index will be used to compute next MCS index.
Wireless Excellence | Date: 2015-04-30
The embodiments herein disclose an indoor personal relay which has a wireless interface with the BS, which is effective in both cost and technology terms. The indoor personal relay, as disclosed herein is an estimate and forward relay. The relay
Wireless Excellence, Indian Institute of Technology Madras and Indian Institute of Technology Hyderabad | Date: 2013-01-18
An Ordered Reduced Set Successive Detector (RSSD) for the V-BLAST spatial multiplexing scheme that uses a general two-dimensional non-uniform set partitioning for different symbols. The detector provides improved diversity and SNR gains at reduced complexity compared to a uniform set partitioning based detector. The detector can be used to reduce the complexity, with a small tradeoff in performance. Further, it is possible to obtain a quasi-ML performance using the disclosed detector at a reduced, yet fixed, complexity.
Wireless Excellence | Date: 2014-07-02
The embodiments herein provide a method and system to trigger UE handover in a radio communication network including a serving base station and a plurality of candidate base stations. The serving base station shares uplink transmission information associated with the UE with the candidate base stations. A candidate base station detects the presence of the UE located in radio coverage of the candidate base station by obtaining information from the uplink transmission of the UE. Further, the candidate base station computes a second parameter and sends to the serving base station. The serving base station determines to trigger handover procedure when the second parameter meets handover criteria. Further, the serving base station sends handover command to the UE after determining that the second parameter meets handover criteria.