For optical transmission at 100 Gb/s and beyond, we propose using coded modulation based on non-binary quasi-cyclic LDPC codes. We show that the proposed schemes offer better performance than their counterparts based ...
详细信息
For optical transmission at 100 Gb/s and beyond, we propose using coded modulation based on non-binary quasi-cyclic LDPC codes. We show that the proposed schemes offer better performance than their counterparts based on bit-interleaved LDPC-coded modulation.
We will present the realization of an envelope tracking (ET) transmitter supporting multi-standard applications. The AB biased harmonic-tuned class-F (class-AB/F) power amplifier with the novel envelope shaping method...
详细信息
We will present the realization of an envelope tracking (ET) transmitter supporting multi-standard applications. The AB biased harmonic-tuned class-F (class-AB/F) power amplifier with the novel envelope shaping method linearly amplifies the input signal with high efficiency. The hybrid switching supply modulator with programmable hysteretic comparator enables the multi-mode operation, whatever the envelope signal characteristics such as the peak-to-average power ratio (PAPR) and the bandwidth are. The designed ET transmitter is fabricated with CMOS 0.13 μm technology and InGaP/GaAs 2 μm HBT process for the supply modulator and the power amplifier, respectively. For IEEE 802.16e m-WiMax signal, it shows a power-added efficiency (PAE), an average output power (Pout), and a gain of 34.3%, 23.9 dBm, 27.9 dB, respectively. At those power levels, without any pre-distortion techniques, it satisfies the overall spectrum emission mask specifications. The relative constellation error (RCE) and the error vector magnitude (EVM) for m-WiMax signal are -30.5 dB and 2.98%, respectively. For a WCDMA signal, it presents a PAE, a Pout, and a gain of 46%, 29 dBm, and 27.8 dB, respectively. For EDGE signal, it delivers a PAE of 45.3% at a Pout of 27.8 dBm with a gain of 29.4 dB. This is the first demonstration of the truly multimode operation of a PA.
In this paper we reduce the feedback overhead in two-stream MIMO with per stream link adaptation and codebook based precoding. The amount of feedback may be reduced by indicating the CQI of one stream in a differentia...
详细信息
In this paper we reduce the feedback overhead in two-stream MIMO with per stream link adaptation and codebook based precoding. The amount of feedback may be reduced by indicating the CQI of one stream in a differential manner. The performance of the system depends on how the differential feedback is designed. We optimize the differential feedback for the weaker data stream by considering an optimum differential quantization between the streams. The off-set CQI values for the weaker stream are found by maximizing the throughput on the weaker data stream using the distribution of the difference between the post processing SINR values of the streams. The SINR difference distribution is found in semi-analytic form for 2 times 2 MIMO with codebook based precoding and a linear receiver. The offset values are calculated for both i.i.d. and correlated flat Rayleigh fading channels for a given number of relative feedback bits.
Irregular Variable Length coding Design for serial concatenated and iteratively decoded Time-Hopping (TH) Pulse Position modulation (PPM) UltraWideBand (UWB) Spread-Spectrum (SS) Impulse radio system is considered. Th...
详细信息
Irregular Variable Length coding Design for serial concatenated and iteratively decoded Time-Hopping (TH) Pulse Position modulation (PPM) UltraWideBand (UWB) Spread-Spectrum (SS) Impulse radio system is considered. The proposed design is capable of low Signal-to-Noise Ratio (SNR) operation in Nakagami-m fading channel amalgamated with joint source and channel coding schemes. A number of component Variable Length coding (VLC) codebooks with different coding rates are being utilized by IVLC scheme for encoding specific fractions of the input source symbol stream. The EXtrinsic Information Transfer (EXIT) charts are used to select these fractions in order to shape inverted EXIT curve of IVLC according to EXIT curve of the inner decoder match. The proposed scheme can achieve near-zero bit error ratio at low SNR values. This IVLC based scheme provides a gain of up to 0.45 dB over the identical-rate single class VLC based scheme.
Irregular LDPC codes can have capacity-approaching performance with an iterative BP decoder under AWGN channel with BPSK modulation. Generally in BPSK modulation, every bit within the block has the same power. In this...
详细信息
Irregular LDPC codes can have capacity-approaching performance with an iterative BP decoder under AWGN channel with BPSK modulation. Generally in BPSK modulation, every bit within the block has the same power. In this paper, we investigate unequal power allocation (UPA) using BPSK modulation for irregular binary LDPC codes. We show that constant power modulation need not lead to the best performance. With UPA we see gains of up to 0.25 dB, with larger gains possible if the receiver knows the details of the UPA scheme. Optimal power allocation is shown to depend strongly on the codes in use. Our work demonstrates the promise of the UPA scheme for some irregular LDPC codes.
Performances of BICM-ID systems strongly depend on the matching between mapping rule and code structure. This paper proposes a combined use of extended mapping (EM) and simple repetition code. Even with such a simple ...
详细信息
Performances of BICM-ID systems strongly depend on the matching between mapping rule and code structure. This paper proposes a combined use of extended mapping (EM) and simple repetition code. Even with such a simple structure, turbo cliff happens at a value range of signal-to-noise power ratio (SNR) 1~2 dB to the Shannon limit. This paper then introduces check node as well as irregular node degree allocation to the proposed structure described above, so that we can flexibly change the shape of the decoder EXIT curve. It is shown that EXIT analysis and chain simulation results exactly match each other.
We address the problem of designing coset codes for use over slow block fading MIMO channels. We consider as inner code different codes built over cyclic algebras (in particular for different number of antennas), and ...
详细信息
We address the problem of designing coset codes for use over slow block fading MIMO channels. We consider as inner code different codes built over cyclic algebras (in particular for different number of antennas), and show that two alternative approaches for the outer code are either codes on cyclic algebras over finite fields, or error correcting codes over finite fields.
Constellation constrained (CC) capacity regions of a two-user Gaussian multiple access channel (GMAC) have been recently reported. For such a channel, code pairs based on trellis coded modulation are proposed in this ...
详细信息
ISBN:
(纸本)9781424443123
Constellation constrained (CC) capacity regions of a two-user Gaussian multiple access channel (GMAC) have been recently reported. For such a channel, code pairs based on trellis coded modulation are proposed in this paper with M-PSK and M-PAM alphabet pairs, for arbitrary values of M; to achieve sum rates close to the CC sum capacity of the GMAC. In particular, the structure of the sum alphabets of M-PSK and M-PAM alphabet pairs are exploited to prove that, for certain angles of rotation between the alphabets, Ungerboeck labelling on the trellis of each user maximizes the guaranteed squared Euclidean distance of the sum trellis. Hence, such a labelling scheme can be used systematically to construct trellis code pairs to achieve sum rates close to the CC sum capacity. More importantly, it is shown for the first time that ML decoding complexity at the destination is significantly reduced when M-PAM alphabet pairs are employed with almost no loss in the sum capacity.
In this paper, we introduce robust cyclic space- frequency (CSF) filtering for systems combining bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). The proposed robust CSF f...
详细信息
In this paper, we introduce robust cyclic space- frequency (CSF) filtering for systems combining bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). The proposed robust CSF filtering scheme exploits outdated channel state information at the transmitter (CSIT) and takes into account the reliability of the CSIT via a Bayesian model. Based on an upper bound on the worst-case pairwise error probability we formulate the optimization problem for the robust CSF filters which can be solved exactly for certain special cases. For the general case, we obtain an approximate solution by solving a related problem with additional constraints. This approximate solution can be further improved with a gradient algorithm for the original problem. Simulation results confirm the excellent performance of BICM-OFDM with robust CSF filtering.
Quasi-synchronous CDMA systems, which can remove co-channel interference by means of synchronization control and use of a ZCZ code, are useful for Short-Range Wireless communications. This paper proposes a BFSK-ZCZ-CD...
详细信息
Quasi-synchronous CDMA systems, which can remove co-channel interference by means of synchronization control and use of a ZCZ code, are useful for Short-Range Wireless communications. This paper proposes a BFSK-ZCZ-CDMA modulation system which appears more advantageous in bit-error-rate performance over multi-path fading channels than ASK or PSK modulation scheme. In this system, a balanced ZCZ code and a quasi-coherent detection with IQ separation are used. The bit-error-rate performances over AWGN and fading channels are simulated.
暂无评论