Roger Pierre Fabris Hoefel

IEEE 802.11n MAC Improvements: A MAC and PHY Cross-Layer Model to Estimate the Throughput

We propose an analytical medium access control (MAC) and physical (PHY) cross-layer model to estimate the saturation net throughput of IEEE 802.11 wireless local area networks (WLANs) with MAC enhancements. These MAC improvements consist of modifications of the IEEE 802.11 distribution coordination function (DCF) MAC protocol in order to support concatenation and multiframe transmission techniques.

IEEE WLANS: 802.11, 802.11e MAC AND 802.11a, 802.11b, 802.11g PHY cross layer link budget model for cell coverage estimation

We develop an analytical medium access control (MAC) and physical (PHY) cross-layer model to calculate the link budget and to estimate the cell coverage of IEEE distributed coordination function (DCF) 802.11 and enhanced distributed coordination function (EDCF) 802.11e wireless local area networks (WLANs). A comparison between numerical and simulation results is carried out assuming the IEEE 802.11a, 802.11b and 802.11g PHY layers.

The fading effects on the CDMA/PRMA network performance

A system level network simulator is developed to assess and to compare some performance aspects of a joint code division multiple access/packet reservation multiple access (CDMA/PRMA) protocol and a random-access (RA)/CDMA protocol over lognormal shadowing, slow and fast fading Rayleigh channels.

IEEE 802.11n: Performance evaluation of modified Viterbi metrics for TxBF, SDM and spatial spreading transceivers

In this paper, we complement the open literature by presenting a comparative performance evaluation between conventional and modified Viterbi metrics for soft-decision decoding of binary convolutional codes in the framework of IEEE 802.11n systems with transmit beamforming, space division multiplexing and spatial spreading transceiver architectures. Simulation results show that the inclusion of channel state information in the Viterbi metrics allows significant performance improvement in the packet error rate over spatially correlated frequency selective TGn channels.

On the Performance of IEEE 802.11n Cyclic Shift Diversity Scheme for 802.11a/g Legacy Compatibility

This paper investigates the legacy compatibility between IEEE 802.11n and 802.11a/g devices, focusing on the performance of legacy 802.11a/g auto-correlation and cross-correlation joint time and frequency synchronization schemes operating over 802.11n networks. It is shown that synchronization schemes based on auto-correlation metric allow the backward compatibility, considering a different number of transmitting antennas operating over TGn channel models.

Throughput and Coverage Analysis of WCDMA and HSDPA Networks

This research deals with a study of case, unifying theoretical and practical aspects, regarding the cell-planning of Wideband Code Division Multiplexing (WCDMA) Release 99 (Rel99) and High Speed Downlink Packet Access (HSDPA) Rel. 5 networks. The used methodology, validated by the close agreement between field and numerical results for throughput and cell coverage, is a useful tool to have first order throughput/coverage prediction results for dimensioning and optimization purposes of advanced wireless networks. The field and analytical results also have confirmed that the HSDPA Rel. 5 allow a higher performance with a similar coverage in relation to that one obtained with a WCDMA Rel. 99 network.

Frame Aggregation and Concatenation Schemes for IEEE EDCF 802.11e: A First Order MAC and PHY Cross-Layer Model to Estimate the Throughput

We develop a first order analytical medium access control (MAC) and physical (PHY) cross-layer model to estimate the saturation net throughput of IEEE 802.11e wireless local area networks (WLANs) with MAC enhancements schemes. The MAC improvements analyzed consist of minor modifications of the IEEE 802.11e enhanced distributed coordination function (EDCF) MAC protocol in order to support frame aggregation and concatenation.

IEEE 802.11n: Effects of Feedback Non-Idealities on Performance of Transmit Beamforming Transceivers

Firstly, we define a set of transmit beamforming (TxBF) transceiver architectures in the framework of IEEE 802.11n systems. In the following, assuming frequency selective spatially correlated TGn D channels, we carry out a comparative performance analysis taking into accounting the effects of realistic time synchronization and channel estimation schemes and practical feedback issues (i.e., delay, quantization and subcarrier grouping) on the throughput gains of the TxBF schemes over the Vertical Bell lab Layered Space Time (V-BLAST) spatial division multiplexing (SDM) scheme.

IEEE 802.11n: Performance Analysis with Spatial Expansion, Receive Diversity and STBC

In this paper, we investigate the effects of transmit antenna correlation, receive antenna correlation, frequency selectivity and imperfect synchronization and channel estimation schemes on the performance of IEEE 802.11n systems with spatial expansion, receive diversity and space-time block codes. The simulations results are validated using a first order analytical modeling.