Enumerative Coding for Grassmannian Space

The Grassmannian space \Gr is the set of all $k-$dimensional subspaces of the vector space~\smash{\F_q^n}. Recently, codes in the Grassmannian have found an application in network coding. The main goal of this paper is to present efficient enumerative encoding and decoding techniques for the Grassmannian. These coding techniques are based on two different orders for the Grassmannian induced by different representations of $k$-dimensional subspaces of \F_q^n. One enumerative coding method is based on a Ferrers diagram representation and on an order for \Gr based on this representation. The complexity of this enumerative coding is $O(k^{5/2} (n-k)^{5/2})$ digit operations. Another order of the Grassmannian is based on a combination of an identifying vector and a reduced row echelon form representation of subspaces. The complexity of the enumerative coding, based on this order, is $O(nk(n-k)\log n\log\log n)$ digits operations. A combination of the two methods reduces the complexity on average by a constant factor.Comment: to appear in IEEE Transactions on Information Theor

Generalized PSK in Space Time Coding

A wireless communication system using multiple antennas promises reliable transmission under Rayleigh flat fading assumptions. Design criteria and practical schemes have been presented for both coherent and non-coherent communication channels. In this paper we generalize one dimensional phase shift keying (PSK) signals and introduce space time constellations from generalized phase shift keying (GPSK) signals based on the complex and real orthogonal designs. The resulting space time constellations reallocate the energy for each transmitting antenna and feature good diversity products, consequently their performances are better than some of the existing comparable codes. Moreover since the maximum likelihood (ML) decoding of our proposed codes can be decomposed to one dimensional PSK signal demodulation, the ML decoding of our codes can be implemented in a very efficient way.Comment: 22 pages, 3 figures, submitted to IEEE transactions on communicaton

A coding scheme for wireless networks with multiple antenna nodes and no channel information

In this paper, we present a coding strategy for wireless relay networks where the relay nodes are small devices with few resources, while the source and sink are equipped with multiple antennas to increase the transmission rate. We assume no channel knowledge at all, and the receiver decodes knowing none of the channel paths. This coding scheme uses distributed space-time coding techniques and is inspired by noncoherent differential space-time coding. It is shown to yield a diversity linear in the minimum number of transmit/receive antennas times the number of relays

Concatenated Space Time Block Codes and TCM, Turbo TCM Convolutional as well as Turbo Codes

Space-time block codes provide substantial diversity advantages for multiple transmit antenna systems at a low decoding complexity. In this paper, we concatenate space-time codes with Convolutional Codes (CC), Turbo Convolutional codes (TC), Turbo BCH codes (TBCH), Trellis Coded Modulation (TCM) and Turbo Trellis Coded Modulation (TTCM) schemes for achieving a high coding gain. The associated performance and complexity of the coding schemes is compared

Advanced channel coding for space mission telecommand links

We investigate and compare different options for updating the error correcting code currently used in space mission telecommand links. Taking as a reference the solutions recently emerged as the most promising ones, based on Low-Density Parity-Check codes, we explore the behavior of alternative schemes, based on parallel concatenated turbo codes and soft-decision decoded BCH codes. Our analysis shows that these further options can offer similar or even better performance.Comment: 5 pages, 7 figures, presented at IEEE VTC 2013 Fall, Las Vegas, USA, Sep. 2013 Proc. IEEE Vehicular Technology Conference (VTC 2013 Fall), ISBN 978-1-6185-9, Las Vegas, USA, Sep. 201

Space-time coding for UMTS. Performance evaluation in combination with convolutional and turbo coding

Space-time codes provide both diversity and coding gain when using multiple transmit antennas to increase spectral efficiency over wireless communications systems. Space-time block codes have already been included in the standardization process of UMTS in conjunction with conventional channel codes (convolutional and turbo codes). We discuss different encoding and decoding strategies when transmit diversity is combined with conventional channel codes, and present simulations results for the TDD and FDD modes of UTRA.Peer ReviewedPostprint (published version