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The performance of hard and soft convolutional channel coding techniques for optical spatial modulation (OSM) are analyzed in this paper. OSM is a recently proposed multiple-input multiple-output (MIMO) technique for indoor optical wireless (OW) communication. In OSM only one transmitter is active at a time and the others are turned off. The spatially separated transmit units are considered as spatial...
Layered Steered Space-Time Codes (LSSTC) is a recently proposed multiple-input multiple-output (MIMO) system that combines the benefits of vertical Bell Labs space-time (VBLAST) scheme, space-time block codes (STBC) and beamforming. We suggest a new downlink scheme employing LSSTC with optimal power allocation, by assuming that the user feeds the BS with the average SNR per VBLAST layer through the...
For multiple-input multiple-output (MIMO) wireless communication system with minimum mean square error (MMSE) detection, power allocation between pilot and data symbols is investigated under MMSE channel estimation in this paper. We first propose a novel soft-output MMSE MIMO detector by taking the channel estimation error into consideration. Then, by random matrix theorem, we propose an effective...
In this paper, we propose a double space-time transmit diversity (DSTTD)-based two-path relay system with power allocation and link combining methods. The two-path relaying protocol can restore spectral efficiency decreased due to the half-duplexing at the relay nodes and the DSTTD method can appropriately achieve the diversity gain from the two paths. To circumvent severe performance degradation...
Coordinated multipoint (CoMP) transmission is being considered in next-generation cellular systems to improve cell-edge throughput. In this paper, we consider open-loop CoMP with L base stations (BSs) where they cooperatively serve a cell-edge user. We first propose antenna selected space-time block code (STBC) to exploit diversity gain for serving the cell-edge user and also support the scenario...
In this paper, serial distributed detection under node failure for wireless sensor networks is studied. All previously suggested distributed detection algorithms for wireless sensor networks assume sensor nodes are completely functional. However, sensor nodes are vulnerable to failure for variety of reasons. Hence, node failure tolerant algorithm design is crucial to provide robustness to system under...
We develop a general model based on random coding bounds to explain and predict the coding performance of various type-I and type-II hybrid automatic repeat request (HARQ) schemes based on the bit-interleaved coded modulation (BICM) in 3GPP HSPA. We explore how the intrinsic properties of BICM interact with various transmitter-side (e.g., whether to use the same bit mapping for retransmission) and...
The IEEE has proposed a narrowband PHY for the IEEE standard of wireless body area network. To maintain small phase transition of the π/2-DBPSK modulated signal and ensure simple receiver design, repetition code is used where lower data rate is needed. In this paper, we suggest to replace the repetition code by Walsh code to improve the interference cancelation capability of the system. Spreading-before-modulation...
Interference problems in cochannel femtocell networks may cause significant performance degradation for certain femtocell/macrocell users. These problems and potential solutions are recently being investigated within the 3GPP. The goal of the present paper is to review the simulation framework for femtocell networks in 3GPP and briefly summarize some of the important inter-cell interference coordination...
We concentrate on the sum power minimization problem for the uplink of wireless cellular systems in this paper. Given a certain quality-of-service (QoS) constraint per mobile station (MS), the optimal power control and receiver beamforming are jointly considered with adaptive multi base station set (MBS) selection for joint reception. An iterative optimization algorithm is proposed accordingly. Although...
This paper presents a new cooperative ARQ with a distributed relay selection that exploits overhearing of inter-relay channels to achieve higher diversity during retransmission. The relays employ decode and forward (DF) to establish the link between the source and the destination. Upon reception from the source, the number of relays available to contend for transmission depends on the conditions of...
In this paper, a new space-frequency combination technique is proposed for Alamouti coded Orthogonal Frequency Division Multiplexing (OFDM) in the context of cooperative communications. Since cooperative antennas are distributed, there may exist multiple carrier frequency offsets (MCFOs) which cause problems for conventional space-frequency decoding. The proposed algorithm, taking cues from existing...
An effective joint radio-frequency (RF) and baseband (BB) hybrid beamforming (HBF) scheme is presented for two-user spatial division multiple access (SDMA) in 60GHz radio using planar antenna arrays (PAA). Taking into account the physical constraints of the phase shifters of PAA, we study the design of downlink HBF from two perspectives of conic optimization: transmit power minimization subject to...
In this paper we propose a novel hybrid multicarrier architecture for wireless LAN (WLAN) applications. We refer to this architecture as hybrid filtered multitone (HFMT). Depending on the experienced channel condition, H-FMT switches between short orthogonal FMT (SO-FMT) modulation, and adaptive orthogonal frequency division multiplexing (A-OFDM). Extensive numerical results show that H-FMT could...
A crucial parameter required for adaptive transmission in orthogonal frequency division multiplexing (OFDM) systems is the signal-to-noise ratio (SNR). In this paper, certain modifications to previously proposed preamble-based SNR estimator for wireless OFDM systems are suggested in order to improve estimation performance. Proposed modifications, related to DFT interpolation, are based on the adaptive...
In this paper, we analyze channel quality indicator (CQI) mismatch probabilities of multiuser orthogonal random beamforming (ORBF) systems. First, we derive the CQI mismatch probability of the ORBF system with M transmit antennas and K users equipped with one receive antenna. Using that result, we also derive the upper and lower bounds of the per user unitary and rate control (PU2RC) system with 2...
Multiple Input Multiple Output (MIMO) opens new challenges to be exploited in Cognitive Radio (CR) by simultaneously serving several users. The spatial domain that is added through MIMO is another system resource that has to be optimized, and shared when possible. In this paper, we present a spatial sharing approach that is carried out through Zero Forcing beamforming (ZFB). Statistical assessment...
Orthogonal frequency division multiplexing (OFDM) systems have enjoyed widespread adoption in high data rate wired and wireless networks, due to their ability to efficiently cope with slowly varying dispersive channels. This paper considers the information theoretic secrecy rates that are achievable by an OFDM transmitter/receiver pair in the presence of an eavesdropper that might either use an OFDM...
Cognitive wireless mesh networks have great potential to green communication. One of the critical challenges for realizing such networks is how to adaptively match transmit powers and allocate frequency resources among secondary users of the licensed frequency bands whilst maintaining the quality-of-service (QoS) requirement of the primary users, even in mutually entangled interferences environment...
Space-frequency block codes (SFBC) combined with frequency switched transmit diversity (FSTD) is used in the downlink of 3GPP LTE system, where all transmit antennas are collocated at eNodeBs. However, all transmit antennas serving a cell are distributed at the cell edge in edge-excited distributed antenna systems. The performance of SFBC is greatly affected by the different large scale fading from...
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