This paper studies a hybrid automatic repeat and request (HARQ) mechanism for multicast/broadcast services in 5G New Radio (NR) systems. HARQ is widely used in unicast transmission to improve reliability and resource ...
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ISBN:
(纸本)9781728112206
This paper studies a hybrid automatic repeat and request (HARQ) mechanism for multicast/broadcast services in 5G New Radio (NR) systems. HARQ is widely used in unicast transmission to improve reliability and resource efficiency under the fading channel. However, for multicast/broadcast, it is difficult to apply conventional HARQ technology because the probability of retransmission becomes high as the number of receiver increases. In this paper, we propose a novel and efficient retransmission scheme, called outer code-based HARQ. After the initial transmission of a given data packet for multicast/broadcast, each receiver sends feedback information on how many code blocks (CBs) are broken instead of which CBs are broken. Then, for retransmission of the data, the transmitter generates parity CBs by using outer code such as Reed-Solomon (RS) or Raptor code and transmits the parity CBs after applying inner code such as low density parity check (LDPC) code. Numerical results show that the proposed scheme outperforms the conventional HARQ schemes, reducing more than 50% of retransmissions.
In this paper, a robust error control coding scheme ispresented. The scheme is a cascaded FEC scheme supported by parityretransmissionsfor furthererrorcorrection in the erroneous data words.The error performance and t...
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In this paper, a robust error control coding scheme is
presented. The scheme is a cascaded FEC scheme supported by parity
retransmissionsfor furthererrorcorrection in the erroneous data words.
The error performance and throughput efficiency of the scheme are
analyzed. Two specific schemes are studied. We show that both schemes
provide high reliability and throughput efficiency even for high channel
bitsrror rates in the range of 10 -*. The schemes are suitable for high
data rate file transfer.
The performanceof two concatenated coding systems usinga K = 3, r = 1/2 convolutional inner code and a Reed-Solomon (15,9)or (15, 7) outer code was measured over a 5.76 km long atmosphericdirect detection optical comm...
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The performanceof two concatenated coding systems using
a K = 3, r = 1/2 convolutional inner code and a Reed-Solomon (15,9)
or (15, 7) outer code was measured over a 5.76 km long atmospheric
direct detection optical communicationchannel. Inner code interleaving
of 100 ps combined with outer code interleaving of 240 bits (60RS
symbols)was found to be sufficientto obtain a decodedBER of less than
under conditions of moderate channel turbulence(U; = 0.6) and
~
an average of 6-10 detected photons per channel bit.
A serial concatenation scheme consisting of a Bose-Chaudhuri-Hocquenghem (BCH) outer code and a Turbo inner code is proposed. We first establish that only a small number of bit positions at the Turbo decoder output ar...
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A serial concatenation scheme consisting of a Bose-Chaudhuri-Hocquenghem (BCH) outer code and a Turbo inner code is proposed. We first establish that only a small number of bit positions at the Turbo decoder output are likely to be in error at high signal-to-noise ratios. A double-error correcting BCH outer code is used to protect these particular error prone bits. Simulation results for an additive white Gaussian noise (AWGN) channel show that the bit-error rate (BER) floor of the Turbo code can be lowered by using this serial concatenation scheme. The proposed technique offers higher throughput efficiency and lower complexity than other serial concatenation schemes.
Average performance bounds based on uniform interleaving are considered for a serial concatenation consisting of an outer code, an interleaver and an inner coded modulation system. The exact input-output weight spectr...
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Average performance bounds based on uniform interleaving are considered for a serial concatenation consisting of an outer code, an interleaver and an inner coded modulation system. The exact input-output weight spectrum is derived for the case when only the outer code has the uniform error property. Thereby, an upper bound to the bit error probability under maximum likelihood detection is obtained. However, numerous examples for serially concatenated continuous phase modulation show that neglecting the non-uniform error property of the inner system gives an accurate and less complex approximation. Other inner coded modulations may behave differently.
This paper considers a hybrid automatic repeat and request (HARQ) scheme of groupcast data transmission for industrial Internet-of-Things (IoT) in 5G New Radio (NR) system. HARQ has been widely used for unicast transm...
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ISBN:
(纸本)9781728109602
This paper considers a hybrid automatic repeat and request (HARQ) scheme of groupcast data transmission for industrial Internet-of-Things (IoT) in 5G New Radio (NR) system. HARQ has been widely used for unicast transmission to improve reliability and resource efficiency. However, it becomes inefficient in industrial loT scenarios that have a lot of target receivers in groupcast data transmission since each receiver may have different part failed to correctly decode. In this paper, a novel and efficient groupcast retransmission scheme for industrial loT services by adopting a concatenated code structure with inner and outer codes is proposed. The amount of retransmitted data is minimized by only transmitting parity code blocks generated by the outer code, e.g., Reed-Solomon (RS) or Raptor code. In addition, the receivers send HARQ feedback information by utilizing the common resources, which can offer the improvement of uplink feedback coverage for IoT devices. Numerical results show that the proposed scheme outperforms the conventional HARQ schemes, reducing more than 50% of retransmissions.
In frequency division multiplexed (FDM) systems, spectral efficiency can be increased by reducing the spacing between two adjacent channels, thus increasing the relevant interference and possibly accounting for it at ...
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ISBN:
(纸本)9781424468331
In frequency division multiplexed (FDM) systems, spectral efficiency can be increased by reducing the spacing between two adjacent channels, thus increasing the relevant interference and possibly accounting for it at the receiver. In this paper, we consider a FDM system where each user employs a continuous phase modulation (CPM), serially concatenated with an outer code through an interleaver, and iterative detection/ decoding. We show that, by taking into account the increased interference using properly designed multiuser detection and synchronization schemes, it is possible to implement transmission schemes with unprecedented spectral efficiency at a price of a limited complexity increase with respect to a classical single-user receiver which neglects the interference.
GPS ephemeris error is a limiting factor in GPS position solution precision. The newly introduced GPS Civil Navigation (CNAV) broadcast message, an upgraded version of the legacy NAV message on the GPS Li signal, is d...
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ISBN:
(纸本)9781632660800
GPS ephemeris error is a limiting factor in GPS position solution precision. The newly introduced GPS Civil Navigation (CNAV) broadcast message, an upgraded version of the legacy NAV message on the GPS Li signal, is designed to provide users with more precise satellite orbit and timing parameters in GPS ephemeris. A CNAV message broadcast test was conducted from June 15th to 29th, 2013 on the L2C and L5 bands Baseband civil GPS signals on Li, L2, and L5 were recorded during the test using wideband software radio front ends. The signals were acquired and tracked, and the navigation messages were decoded by the conventional Viterbi method and a more computationally efficient matrixbased method. GPS ephemerides were extracted from the CNAV messages to compute satellite orbit solutions. In this paper, the orbit solution accuracy is compared with that computed from Legacy NAV messages during the same time period to demonstrate the improvements in the CNAV ephemeris precision.
5G systems are supposed to support coexistence of multiple services such as ultra reliable low latency communications (URLLC) and enhanced mobile broadband (eMBB) communications. The target of eMBB communications is t...
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ISBN:
(数字)9781510616042
ISBN:
(纸本)9781510616042
5G systems are supposed to support coexistence of multiple services such as ultra reliable low latency communications (URLLC) and enhanced mobile broadband (eMBB) communications. The target of eMBB communications is to meet the high-throughput requirement while URLLC are used for some high priority services. Due to the sporadic nature and low latency requirement, URLLC transmission may pre-empt the resource of eMBB transmission. Our work is to analyze the URLLC impact on eMBB transmission in mobile front-haul. Then, some solutions are proposed to guarantee the reliability/latency requirements for URLLC services and minimize the impact to eMBB services at the same time.
Part I of a two-part series investigates product accumulate codes, a special class of differentially-encoded low density parity check (DE-LDPC) codes with high performance and low complexity, on flat Rayleigh fading c...
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Part I of a two-part series investigates product accumulate codes, a special class of differentially-encoded low density parity check (DE-LDPC) codes with high performance and low complexity, on flat Rayleigh fading channels. In the coherent detection case, Divsalar's simple bounds and iterative thresholds using density evolution are computed to quantify the code performance at finite and infinite lengths, respectively. In the noncoherent detection case, a simple iterative differential detection and decoding (IDDD) receiver is proposed and shown to be robust for different Doppler shifts. Extrinsic information transfer (EXIT) charts reveal that, with pilot symbol assisted differential detection, the widespread practice of inserting pilot symbols to terminate the trellis actually incurs a loss in capacity, and a more efficient way is to separate pilots from the trellis. Through analysis and simulations, it is shown that PA codes perform very well with both coherent and noncoherent detections. The more general case of DE-LDPC codes, where the LDPC part may take arbitrary degree profiles, is studied in Part II Li 2008. Copyright (C) 2008 Jing Li (Tiffany).
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