Early carboniferous brachiopod faunas from the Baoshan block, west Yunnan, southwest China

38 brachiopod species in 27 genera and subgenera are described from the Yudong Formation in the Shidian-Baoshan area, west Yunnan, southwest China. New taxa include two new subgenera: Unispirifer (Septimispirifer) and Brachythyrina (Longathyrina), and seven new species: Eomarginifera yunnanensis, Marginatia cylindrica, Unispirifer (Unispirifer) xiangshanensis, Unispirifer (Septimispirifer) wafangjieensis, Brachythyrina (Brachythyrina) transversa, Brachythyrina (Longathyrina) baoshanensis, and Girtyella wafangjieensis. Based on the described material and constraints from associated coral and conodont faunas, the age of the brachiopod fauna from the Yudon Formation is considered late Tournaisian (Early Carboniferous), with a possibility extending into earlyViseacutean.<br /

Linear and DF joint detectors for DS-CDMA communications using periodic long codes

Detection structures for a direct sequence (DS) code division multiple access (CDMA) multiuser uplink using codes with a period of several symbols, called long codes, are investigated. In a first part, we propose a multirate description of the uplink. Based on this formalism, we revisit the linear and decision feedback minimum mean square error (MMSE) detectors. In order to identify the best attainable performance, we focus on the infinite size versions. In a second part, reduced complexity, solutions are put forward and discussed. Finally, the performance of the proposed detectors is investigated and compared with that of the classical rake receiver and the single-bit horizon detectors. The relevance of the different solutions is discussed in the light of the channel length

Cyclic prefixed single carrier and multicarrier transmission: Bit rate comparison

We consider cyclic prefixed single carrier and adaptive multicarrier transmission over a frequency selective channel. We compare the achievable bit rate for a target bit error rate. We analytically prove that the bit rate achieved with multicarrier transmission with adaptive modulation is always higher than that obtained with single carrier transmission when a one-tap frequency domain equalizer is used. We also show that the same adaptively loaded multicarrier scheme reaches the performance of single carrier transmission with a block decision-feedback equalizer

Early-late timing recovery with decision-feedback equalizers

In this paper we revisit the early-late timing recovery scheme developed for filter bank based multicarrier transmission. A substantial improvement is proposed for the case where the receiver contains a decision-feedback equalizer. We show how the timing error detector has to be modified to account for the high level of self-noise and how this self-noise can be mitigated thanks to the introduction of a correction term. We investigate the tracking performance of this new synchronizer for high bit rate transmission over copper wires.Anglai

Balanced capacity of wireline multiple access channels with individual power constraints

This paper applies the concept of balanced capacity, a fair trade-off between individual and global performance, to the uplink of a Gaussian frequency-selective multiuser channel with K users, where K can be much larger than 2. Individual power constraints are applied to each transmitter, which makes the computation of the balanced capacity very complex. The concept of 'equivalent channel' is used to derive an explicit expression of the optimal power allocation, that remains compatible with the individual power constraints. The computation of the balanced capacity is then formulated as a set of 2K nonlinear equations. An iterative algorithm providing the exact solution is firstly introduced. A suboptimal solution, based on the Iterative Multiuser Water-Filling (IMWF) algorithm, is then proposed and shown to be very close to the optimal solution: The idea of this alternative method, called 'balanced water-filling', is to modify the power allocation obtained with the IMWF algorithm in order to get balanced data rates. Results are provided for a wireline access network with 20 users

Balanced capacity of wireline multiuser channels

This paper analyzes the multiuser capacity of Gaussian frequency-selective wireline multiaccess channels. Both the uplink (multiple-access channel) and downlink (broadcast channel) capacity regions are considered. The concept of balanced capacity is introduced to characterize the multiuser channel performance. Algorithms for the computation of the balanced multiuser capacity (and the associated power allocations) are proposed for an arbitrary number of users. The optimal power allocation in a K-user memoryless Gaussian channel is analyzed in detail, and an extension to intersymbol interference channels is given with various kinds of power constraints. Results are provided for a wireline access network with 20 users