The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We consider two-hop S-R-D Gaussian networks with a source (S), a relay (R) and a destination (D), some of which experience additive interference. This additive interference, which renders the channels state-dependent, is either a) experienced at the destination D and known non-causally at the source S, or b) experienced at the relay R and known at the destination D. In both cases, one would hope to...
A rewriting code construction for flash memories based upon lattices is described, where the values stored in flash cells correspond to lattice points. This construction encodes information to lattice points in such a way that data can be written to the memory multiple times without decreasing the cell values. The construction partitions the flash memory's cubic signal space into blocks, which aids...
We propose the notion of secrecy gain as a code design criterion for wiretap lattice codes to be used over an additive white Gaussian noise channel. Our analysis relies on the error probabilites of both the legitimate user and the eavesdropper. We focus on geometrical properties of lattices, described by their theta series, to characterize good wiretap codes.
This paper considers certain aspects of some well-known multiple-input single-output (MISO) codes. In the first section it is proved how in some special cases the n + 1 MISO channel can be seen as consisting of several parallel MISO channels having less transmit antennas. It is also pointed out that unitary conjugation does not change the diversity-multiplexing tradeoff (DMT) of a code. These simple...
We consider the Gaussian interference channel with an intermediate relay. The known achievable schemes for this channel are based on decode-and-forward (DF) relaying, whose performance depends on the signal-to-noise (SNR) ratio of the received signal at the relay. Consequently, when the source-to-relay (S-R) links are weak, the resulting achievable rates have room for improvement. In this work, we...
In two-way relaying, two sources exchange information via a relay. In the generalized two-way relay, private information is also sent by each source to the relay, which may be used for overhead data, such as for channel state information. We consider the generalized two-way relay in a multi-carrier system over the wireless channel. Our problem is to maximize the rate that the sources exchange information,...
This paper analyzes Gaussian interference channels with more than two users and integer channel gains, and finds a new achievable set of rates using lattice codebooks. It combines lattices with alignment schemes inspired by the ones developed for degrees of freedom (DoF) analysis and shows that similar rate gains can be achieved for finite SNR interference networks as well. In essence, this work can...
In this work, we prove that a positive secure degree of freedom is achievable for a large class of real Gaussian channels as long as the channel is not degraded and the channel is fully connected. This class includes the MAC wiretap channel, the 2-user interference channel with confidential messages, the 2-user interference channel with an external eavesdropper. Best known achievable schemes to date...
In the two-way relay channel, two sources exchange information with help from a relay. We study a more general relay network with additional pairs of sources that perform pair-wise information exchange. We obtain achievable rate regions for amplify-and-forward and decode-and-forward (DF) relaying schemes based on both Gaussian codes and lattice codes, assuming a two-phase protocol. The lattice-code-based...
A new class of spherical codes is constructed by selecting a finite subset of flat tori that foliate the unit sphere S2L-1 sub R2L and constructing a structured codebook on each torus in the finite subset. The codebook on each torus is the image of a lattice restricted to a specific hyperbox in RL. Group structure and homogeneity, useful for efficient decoding, are inherited from the underlying lattice...
In recent work, we have shown that in a Gaussian network, nodes can often recover linear combinations of transmitted codewords much more efficiently than the codewords themselves. These nodes, after decoding their linear equations, simply send them towards the destination, which given enough equations, can recover the desired messages. This compute-and-forward strategy relies on a lattice-based coding...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.