Raja S. Bachu
Motorola
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Publication
Featured researches published by Raja S. Bachu.
personal, indoor and mobile radio communications | 2005
Fan Wang; Amitava Ghosh; Robert T. Love; Kenneth A. Stewart; Rapeepat Ratasuk; Raja S. Bachu; Yakun Sun; Qing Zhao
In this paper, the performance of a prototypical IEEE 802.16e network is analyzed via link and system simulations. The exponential effective SIR mapping (EESM) is used to map the instantaneous SINR of received signals to a service-specific packet erasure rate (PER), which is in turn used to assess the downlink and uplink network and user data throughput. A variety of data traffic models are considered, including web browsing (HTTP) and full buffer sessions, operating in flat-fading and frequency-selective multipath channels such as the ITU Pedestrian-B model. The downlink network performance of the prototypical IEEE 802.16e network is compared to a 3GPP UMTS high speed downlink packet access (HSDPA) system of similar physical dimensions. System simulation results for the prototypical IEEE 802.16e network considered show-when frequency-selective scheduling is not applied-that the IEEE 802.16e downlink has similar throughput performance as HSDPA for a 70/30 TDD DL/UL frame split but approximately 40%-50% higher spectral efficiency, although control channel overhead and uplink capacity limitation remain significant open issues for further study
personal, indoor and mobile radio communications | 2002
Amitava Ghosh; Kenneth A. Stewart; Rapeepat Ratasuk; E. Buckley; Raja S. Bachu
The paper compares two hybrid automatic repeat request (HARQ) schemes using incremental redundancy (IR) which have been proposed for the UMTS (W-CDMA) high speed downlink shared channel (HS-DSCH). Their relative throughput performance is reported for various channel conditions. It is shown that the two-stage rate-matching scheme has marginally worse performance compared to the alternative block interleaving scheme for certain coding rates and under some channel conditions.
personal, indoor and mobile radio communications | 2006
Raja S. Bachu; Guocong Song; Kenneth A. Stewart; Xiangyang Zhuang
Next generation wireless systems, such as the IEEE 802.16e specification, are designed to provide great flexibility in scheduling radio resources on a per frame basis. Such flexibility, coupled with the need to maintain good quality of service (QoS) for cell-edge users can, however, lead to significant control channel overhead especially when using low code rates to maintain cell edge coverage. It is shown here that in interference-limited scenarios dual antenna mobile stations (MS) equipped with interference cancellation (IC) receivers can significantly alleviate this problem. In this study, the performance of a linear MMSE IC receiver is evaluated both at the link level and at the network level. It is shown that a practical IC receiver can achieve link performance gains in the range of 2.5-14 dB over a maximal ratio combining (MRC) receiver in single interferer dominant conditions. Performance at the network level is evaluated using the well-known EESM method to model the link-level performance for OFDM systems, and the introduction of IC receivers at the MS is shown to increase control channel coverage by 10-24% at low codeword repetition factors
Archive | 2005
Robert T. Love; Raja S. Bachu; Brian K. Classon; Ravikiran Nory; Kenneth A. Stewart; Yakun Sun
Archive | 2003
Kenneth A. Stewart; Raja S. Bachu; Michael E. Buckley; Clint S. Wilkins
Archive | 2006
Raja S. Bachu; Michael E. Buckley; Ravi Kuchibhotla; Robert T. Love; Kenneth A. Stewart; Jianzhong Zhang
Archive | 2001
Kenneth A. Stewart; Amitava Ghosh; Michael E. Buckley; Raja S. Bachu; Rapeepat Ratasuk
Archive | 2003
Michael E. Buckley; Raja S. Bachu; Kenneth A. Stewart; Clint S. Wilkins
Archive | 2011
Kenneth A. Stewart; Jean-Aicard Fabien; Michael E. Buckley; Raja S. Bachu
Archive | 2002
Michael E. Buckley; Raja S. Bachu; Amitava Ghosh; Rapeepat Ratasuk; Kenneth A. Stewart; Mathieu Villion