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.
Channel log-likelihood ratio (LLR) calculation on many communication channels is a challenging task especially when non-binary modulations are used. This is because LLRs are usually complicated functions of the channel output and their calculation also requires knowledge of the channel parameters. In this paper, we consider the problem of finding good approximate LLRs for the additive white Gaussian...
In this paper, we study coding techniques for the multiple-input multiple-output multi-hop amplify-and-forward (MIMO-MH-AF) block-fading channel. We first derive conditions on coding rates and space-time precoders that allow a coded modulation to achieve the diversity order provided by the channel. We then derive a bound on the diversity order of a coded modulation so as to attain maximum diversity...
In this paper, soft-decision decoding is considered as an optimisation problem and a computationally efficient soft-decision decoding algorithm for block codes is developed using a compact Genetic Algorithm. The performance of this algorithm is investigated and compared with other decoding schemes. The results show the proposed algorithm gives large gains over the Generalised Minimum Distance (GMD)...
In this paper, a powerful class of irregular low-density parity check (LDPC) codes based on random construction techniques is presented. The resultant codes have accurate profile with the additional features of making them suitable for incremental redundancy systems. The proposed codes also have low encoding complexity and can be decoded efficiently. Moreover, these codes show better puncturing performance...
Time-invariant low-density parity-check convolutional codes (LDPCccs) can be constructed from a polynomial form of a parity-check matrix that defines quasi-cyclic LDPC block codes based on circulant matrices. Based on this polynomial matrix, we discuss the relationships between the polynomial domain and the time domain parity-check and syndrome former matrices with respect to cycle properties. We...
Using an appropriate multi-access channel model, we consider CDMA network transmission with single-user demodulation and decoding at the receiver. We derive the asymptotic distribution of the multi-user interference in case of high-rate transmission that can exceed the conjectured CDMA capacity with Gaussian multi-user interference. We show that the considered multi-user interference is non-Gaussian...
Divsalar and Simon showed that with multi-symbol differential detection, the performance gap between two-symbol differential detection and coherent detection of differentially encoded phase shift keying can be closed. To close this gap for single-carrier differentially encoded phase shift keying with interleaving and convolutional encoding, Peleg et al. proposed a joint and iterative multi-symbol...
In this work we study encoding/decoding schemes for the transmission of a discrete time analog Gaussian source over a Gaussian wiretap channel. The intended receiver is assumed to have a certain minimum signal to noise ratio (SNR) and the eavesdropper is assumed to have a strictly lower SNR compared to the intended receiver. For a fixed information leakage rate (Iϵ) to the eavesdropper, we are interested...
The bidirectional broadcast channel denotes a broadcast channel with two receivers where each receiver knows the message intended for the other. Exponentially decreasing upper bounds on the average error probability using maximum likelihood decoders are derived based on Gallager's results for the point-to-point channel. The bounds are coupled by the common input distribution and provide an alternative...
First, the Han-Kobayashi (HK) rate region for general interference channel (IC) is partially improved allowing the input random variables to be correlated. Second, considering a general input distribution and using a combination of the HK jointly decoding strategy, Marton like coding and binning scheme, we obtain a new achievable rate region for the cognitive radio channel (CRC) and show that this...
We consider a variety of memoryless discrete-time noisy communication channels where the noise is modeled as an additive white Gaussian noise process, and where the input of the channel is distorted according to a deterministic function f(X) of the form i) f(X) = αXn ii) f(X) = α|X|n iii) f(X) = α|X|1/q iv) f(X) = αsgn(X)|X|1/q, for all α ϵ R*, n ϵ N*\{1}. Subject to an average power constraint, we...
In this paper, we investigate the outage performance of Decode-and-Forward with partial selection relaying in dual-hop cooperative Nakagami-m fading links. The source, based on the unique knowledge of local first hop channel state information, selects the best relay to increase the chances of successful decoding and hence the possibility of cooperation when the direct link is also available. After...
We consider a multiple access primary network with N transmitters. A secondary link of one transmitter and a corresponding receiver causes interference to the primary network. An achievable rate region for the primary network and the secondary link is obtained given the following mode of operation. The secondary transmitter employs rate-splitting so that the primary receiver can decode part of the...
Motivated by the GSM system, we consider communication systems which employ the encoding-encryption paradigm of first encoding the data before encrypting it for transmission. We add one level of security to the existing system designs by introducing a wiretap encoder. We analyze the security from an information theoretical point of view, and prove the enhanced security of the proposed scheme, focusing...
Many papers reporting microelectronic chaos based applications have appeared in recent years. The focus of cryptology has been mainly on the algorithm implementation rather than on the chaotic system choice. In this paper, a novel method is proposed which aims at properly selecting a chaotic system to be used with encryption algorithms. The properties directly related to the algorithm strength and...
In this paper, a novel Bitplane-LVQ technique to compress subbands bitplane coefficients is proposed for multiple description coding (MDC) system. The MDC system utilizes three descriptions with one central decoder and three side decoders. The significant bitplanes subband coefficients are encoded using lattice D2 which the number of bitplanes (k) ties with the amount of compression ratio. The residual...
This paper addresses the problem of efficient data gathering in wireless sensor networks with a complexity constrained data gathering node. A particular scenario of interest is a cluster of sensor nodes among which one is selected as the cluster head. Distributed source coding allows for exploiting the dependency between the nodes observations and reducing the required rate of communications. We consider...
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.