On Superposition Coding for Wireless Broadcast Channels (original) (raw)
Related papers
Superposition Coding Strategies: Design and Experimental Evaluation
IEEE Transactions on Wireless Communications, 2000
We design and implement a software-radio system for Superposition Coding (SC), a multiuser transmission scheme that deliberately introduces interference among user signals at the transmitter, using a library of off-the-shelf point-to-point channel codes. We experimentally determine the set of ratepairs achieved by this transmission scheme under a packet-error constraint. Our results suggest that SC can provide substantial gains in spectral efficiencies over those achieved by orthogonal schemes such as Time Division Multiplexing. Our findings also question the practical utility of the Gaussian approximation for the inter-user interference in Superposition-Coded systems.
Implementation and experimental results of superposition coding on software radio
2010
In theory, multi-user techniques such as superposition coding (SPC) are known to improve throughput in wireless networks. However, in order to understand their practical limitations, it is imperative to actually implement and experiment with such techniques in a realistic setting. In this paper, we present the design of a software radio-based implementation of SPC using the GNU Radio architecture. We describe software and hardware issues associated with SPC implementation on a Universal Software Radio Peripheral (USRP) board. We then experimentally evaluate the performance of this SPC system and demonstrate how it compares to a time-division multiplexing (TDM) system.
Performance analysis of superposition coded modulation
Physical Communication, 2010
This paper presents a comprehensive analysis of superposition coded modulation (SCM). Two types of SCM schemes, i.e., the single-code SCM (SC-SCM) and multi-code SCM (MC-SCM), are analyzed. The basic features of SCM are described, followed by the information-theoretic analysis. Different encoding/decoding strategies are compared from the capacity point of view. A semi-analytical evolution technique is proposed to track the convergence
Application of Superposition Coding for Subcarrier and Bit Allocation in Downlink OFDM Systems
International Journal of Information and Electronics Engineering, 2012
Orthogonal frequency division multiplexing (OFDM) is well known for multicarrier modulation technique in which a high data rate stream is divided into different parallel lower data stream. In this paper, we study the margin adaptive-superposition coding (MA-SC) algorithm and rate adaptive-superposition coding (RA-SC) algorithm, where at most two user can share each subcarrier as compared to MA and RA algorithm, where each subcarrier is shared by only single user without SC scheme. We apply SC scheme over MA and RA to achieve maximum system throughput with separate power constraint for real and non real time users, ensuring that QoS requirement for real time and proportional fairness among non real time users is satisfied. The overall computational complexity of proposed modified RA-SC algorithm is same as RA algorithm. In the modified proposed MA-SC, complexity increases in some of the steps due to addition of SC scheme over MA algorithm, but overall complexity remains the same. Monte-Carlo simulations are being carried out to show that the proposed algorithm improves the performance in terms of power required and throughput.
A Plotkin-Alamouti Superposition Coding Scheme for Cooperative Broadcasting in Wireless Networks
2009
This paper deals with superposition coding for cooperative broadcasting in the case of two coordinated source nodes, as introduced in the seminal work of Bergmans and Cover in 1974. A scheme is introduced for two classes of destination (or relay) nodes: Close nodes and far nodes, as ranked by their spatial distances to the pair of transmitting nodes. Two linear codes are combined using the |u|u + v|-construction devised by Plotkin to construct two-level linear unequal error protection (LUEP) codes. However, instead of binary addition of subcode codewords in the source encoder, here modulated subcode sequences are combined at the destination (or relay) nodes antennae. Bergmans and Cover referred to this as over-the-air mixing. In the case of Rayleigh fading, additional diversity order as well as robustness to channel estimation errors are obtained when source nodes transmit pairs of coded sequences in accordance to Alamouti's transmit diversity scheme. We refer to this combination as a Plotkin-Alamouti scheme and study its performance over AWGN and Rayleigh fading channels with a properly partitioned QPSK constellation.
Analysis of the Benefits of Superposition Coding in Random Wireless Networks
2010 Ieee International Symposium on Information Theory, 2010
Network-wide adoption of a multipacket transmission scheme such as Superposition Coding (SC) for local "oneto-many" communication results in mutually interfering "broadcast" clusters. We analyze the benefits of SC and traditional Frequency Division (FD) with this interference via a utility function that measures the rate of information transfer per unit area. In particular, we study transmitters forming a Poisson point process and using ALOHA for medium access. For a fixed bandwidth allocation, FD allows spatial reuse to be independently optimized for each frequency band. On the other hand, with SC for a fixed power allocation, the optimal spatial reuse depends on the relative contribution of each link to the utility function. Since optimal spatial reuse is a function of the network geometry, the gains provided by SC depend on the geometry of the receiver node placement.
Scheduling using Superposition Coding: Design and Software Radio Implementation
2011 Ieee Radio and Wireless Symposium (Rws), 2011
Cellular base stations typically orthogonalize downlink transmissions, although this approach is not always throughput-optimal. Indeed, it can be shown that removing the orthogonality constraint (as in Superposition Coding) can provide significant benefits in some scenarios. Based on this principle, we propose a scheduling algorithm for a two-user downlink that leverages the disparity in their respective channel qualities. By a judicious reallocation of the transmit power and bandwidth, this algorithm improves the throughput to both users vis-à-vis an orthogonal scheme. We design a softwaredefined radio platform to implement the scheduler and experimentally verify the gains promised by theory.
Superposition coded modulation
2009
Coded modulation (CM) is an eective high-rate transmission technique that has attracted tremendous attention. The revolutionary trellis coded modulation (TCM) scheme can achieve high spectrum-and power-eciencies based on the joint design of coding and modulation. However, it requires a specially-tailored code for each particular transmission rate. This issue can be tackled by multi-level codes (MLC) and bit-interleaved coded modulation (BICM) where the on-shelf binary codes can be directly applied. All these CM schemes can yield signicant coding gains. However, they still suer from capacity loss, high decoding and design complexities. Superposition coded modulation (SCM) is an alternative CM scheme recently proposed. Compared with conventional schemes which usually employ non-linear bit-to-symbol mapping, SCM produces transmit signals by superimposing independent binary coded sequences (each referred to as a layer). By properly choosing the weighting factors, the same binary component code can be used at all layers. This greatly simplies the search of good component codes. Furthermore, thanks to the linearity involved, a successive-interference cancelation (SIC)-type receiver
ArXiv, 2020
A general inner bound is given for the discrete memoryless broadcast channel with an arbitrary number of users and general message sets, a setting that accounts for the most general form of concurrent groupcasting, with messages intended for any set of subsets of receivers. Achievability is based on superposition coding and rate-splitting without and with binning, where each receiver jointly decodes both its desired messages as well as the partial interference assigned to it via rate-splitting. The proof of achievability builds on the techniques for the description and analysis of superposition coding recently developed by the authors for the multiple-access channel with general messages as well as a new recursive mutual covering lemma for the analysis of the more general achievable scheme with binning.