C:/Documents and Settings/clin/Desktop/CISS-2008/CISS-08-lrv-dft3.dvi

نویسندگان

  • Che Lin
  • Vasanthan Raghavan
  • Venugopal V. Veeravalli
چکیده

Space-time codes have been designed over the last decade to enhance the reliability of open-loop fading wireless systems. However, recent technological advances have enabled the possibility of low-rate feedback from the receiver to the transmitter. The focus of this work is on the implications of this feedback in a point-to-point MIMO system with a coherent receiver and a general model for spatial correlation that is known at the transmitter. We assume that B bits of quantized channel information are available at the transmitter. Coding over space-time is then studied by considering the family of linear dispersion (LD) codes that meets an additional orthogonal condition, which leads to a decoding complexity comparable to orthogonal space-time block codes (OSTBC). Our results show that, when B is small, a space-time coding scheme that is equivalent to beamforming and does not code across time is optimal in a weak sense in that it maximizes the average received SNR. As B increases, this weak optimality transitions to optimality in a strong sense characterized by the maximization of the average mutual information. Hence, from a system designer’s perspective, our work suggests that beamforming may not only be attractive from a low-complexity viewpoint, but also from an information-theoretic viewpoint.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Trigeminal ganglion and its divisions: detailed anatomic MR imaging with contrast-enhanced 3D constructive interference in the steady state sequences.

BACKGROUND AND PURPOSE Visualization of the trigeminal system is important for imaging diagnosis but technically challenging. We assessed how well the trigeminal ganglion, its rootlets, and its branches (V1, V2, and V3) are depicted on three high-resolution pulse sequences. METHODS Twenty-two patients (44 sides) underwent nonenhanced 3D constructive interference in the steady state (CISS) MR ...

متن کامل

Validity and reliability of the revised convergence insufficiency symptom survey in children aged 9 to 18 years.

PURPOSE To assess the validity and reliability of the Convergence Insufficiency Symptom Survey (CISS) in children aged 9 to 18 years. The CISS is the primary outcome measure for a pilot study evaluating two different treatments for convergence insufficiency (CI). METHODS Children with CI were given the CISS twice to assess reliability. CISS scores for the first administration were also compar...

متن کامل

Differentiation between paraclinoid and cavernous sinus aneurysms with contrast-enhanced 3D constructive interference in steady- state MR imaging.

BACKGROUND AND PURPOSE Differentiation between paraclinoid and cavernous sinus aneurysms of the internal carotid artery (ICA) is critical when considering treatment options. The purpose of this study was to determine whether contrast-enhanced (CE) 3D constructive interference in steady state (CISS) MR imaging is useful to differentiate between paraclinoid and cavernous sinus aneurysms. MATERI...

متن کامل

Tolosa–Hunt Syndrome Demonstrated by Constructive Interference Steady State Magnetic Resonance Imaging

PURPOSE To highlight the role of constructive interference steady state (CISS) magnetic resonance imaging (MRI) in the diagnosis of Tolosa-Hunt Syndrome (THS). CASE REPORT We describe a case of THS in a 55-year-old woman presenting with left painful opthalmoplegia that was diagnosed by CISS MRI. Patient responded to steroid treatment and the lesion resolved. CONCLUSION Imaging with MRI can ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2008