BACKGROUND: The treatment and prognosis of lung adenocarcinoma (LUAD) remains a challenge. The study aimed to conduct a systematic analysis of the predictive capacity of N6-methyladenosine (m6A)-related long non-coding RNAs (lncRNAs) in the prognosis of LUAD. METHODS: 594 samples were totally selected from a dataset from The Cancer Genome Atlas. The identification of prognostic m6A-related lncRNAs were performed by Pearson correlation analysis and Cox regression analysis. Systematic analyses, including cluster analysis, survival analysis, and immuno-correlated analysis, were conducted. A prognosis model was built from the optimized subset of m6A-related lncRNAs. The assessment of model was performed by survival analysis, and receiver operating characteristic (ROC) curve. Finally, the risk score of patients with LUAD calculated by the prognosis model was implemented by the analysis of Cox regression. Differential analysis was for further evaluation of the cuproptosis-related genes in two risk sets. RESULTS: These patients were grouped into two clusters according to the expression levels of 22 prognostic m6A-related lncRNAs. The patients with LUAD in cluster 2 was significantly worse in the overall survival (OS) (P = 0.006). Three scores calculated by the ESTIMATE methods in cluster 2 were significantly lower. After the least absolute shrinkage and selection operator algorithm, 10 prognostic m6A-related lncRNAs were totally selected to construct the final model to obtain the risk score. Then the area under the ROC curve of the prognosis model for 1, 3, and 5-year OS was 0.767, 0.709, and 0.736 in the training set, and 0.707, 0.691, and 0.675 in the test set. The OS of the low-risk cohort was significantly higher than that of the high-risk cohort in both the training set (P < 0.001) and test set (P < 0.001). After the analysis of Cox regression, the risk score [Hazard ratio (HR) = 5.792; P < 0.001] and stage (HR = 1.576; P < 0.001) were both considered as independent indicators of prognosis for LUAD. The expression levels of five cuproptosis-related genes were significantly different in two risk sets. CONCLUSIONS: The study constructed a predictive model for the OS of patients with LUAD and these OS-related m6A-lncRNAs might have potential roles in LUAD progression.

This paper derives closed-form asymptotic symbol error rates (ASERs) for MPSK and MQAM signals with selection combining (SC) over Nakagami-m fading channels. It also presents a closed-form expression for the power loss of SC compared to maximal ratio combining (MRC) over a Nakagami- m fading channel. It is found that this power gap is a function of only the number (L) of independent Nakagami-m channels and the fading parameter m. For a fixed m, the gap monotonically increases with L. For a fixed L, the gap monotonically increases with m and approaches 10 log10L dB (the asymptotic gap between MRC and SC in an AWGN channel) as m ¿ ¿. In addition, numerical results show the accuracy of the ASERs obtained from closed-form expressions for both MRC and SC with MPSK and MQAM signals for large SNRs. They also show that the SNR gap is identical to that predicted by the analysis for arbitrary L and m.

Reference introduced optimum selection combining (OSC) for binary phase shift keyed signals which selects the diversity branch having the maximum a posteriori probability. It performs much closer to maximal ratio combining (MRC) than the conventional selection combining (CSC) which selects the diversity branch having the maximal instantaneous signal power. It is known that these combining techniques have the same diversity order (DO), i.e., the same performance slope (log error probability versus signal-to-noise ratio (SNR) in dB)-the performance variation is the SNR difference (gap) between any two techniques to achieve the same bit error rate (BER). This paper derives closed-form expressions for the SNR gaps among these three combining schemes. The paper also analyzes the asymptotic BER for these three combining schemes as a function of DO for a fixed SNR.

This paper derives closed-form asymptotic symbol error rates (ASERs) for MPSK and MQAM signals with selection combining (SC) over Nakagami-m fading channels. It also presents a closed-form expression for the power loss of SC compared to maximal ratio combining (MRC) over a Nakagami-m fading channel. It is found that this power gap is a function of only the number (X) of independent Nakagami-m channels and the fading parameter m. For a fixed m, the gap monotonically increases with L. For a fixed L, the gap monotonically increases with m and approaches10log10L dn (the asymptotic gap between MRC and SC in an AWGN channel) as m rarr infin . In addition, numerical results show the accuracy of the ASERs obtained from closed-form expressions for both MRC and SC with MPSK and MQAM signals for large SNRs. They also show that the SNR gap is identical to that predicted by the analysis for arbitrary L and m.

This paper presents a simple way to obtain the asymptotic performance of various digital communications systems operating over fading channels. The resulting expression for performance contains only the inverse average SNR raised to the system's diversity order, by averaging the conditional error probability (conditioned on the fading) with the dominant term in the fading density function. The proposed approach often renders simple closed-form asymptotic error probabilities (ASEPs), even when the corresponding closed-form actual error probabilities (ACEPs) are too difficult to find, such as those in generalized selection combining, denoted by GSC (m,L), where the strongest m branches from L (1lesmlesL) total branches are selected and combined Using the proposed approach, the paper derives simple closed-form ASEPs for GSC (m,L) which show its diversity order and SNR gaps among different m, over both iid and non-iid Rayleigh fading channels for both MPSK and QAM. It is found that the SNR gaps of GSC (m,L) are not a function of modulation type or orders. In addition, the paper also presents simple closed-form ASEPs for a Nakagami-m fading channel with both MPSK and QAM in conjunction with maximal ratio combining (MRC).

This letter presents a new optimum interference mitigating combining (OIMC) scheme for the code-division multiple-access downlink RAKE receiver. The OIMC scheme optimizes the RAKE weights and maximizes the signal-to-interference-plus-noise ratio (SINR) at the RAKE combiner output. Unlike other interference mitigation schemes, the new scheme does not need to estimate the interference or data correlation matrix (and its inverse) of the received signal to render a reliable and low complexity receiver. The OIMC scheme mitigates interference by inversely proportionately weighting the finger output by its associated interference power, while simultaneously mitigating multipath fading. The interference power is found to be directly related to the finger's associated multipath channel gain, rendering the OIMC scheme with the same order of complexity as a maximal ratio combining (MRC) scheme. Under realistic channel conditions, simulation results show that the proposed OIMC scheme always outperforms MRC with a gain of up to more than 1 dB.

This paper presents a new optimum combining scheme for a CDMA wireless mobile receiver. The new combining scheme, compared to conventional maximal ratio combining (MRC), not only combats multi-path fading, but also mitigates interference by further scaling the finger output inversely proportional to its total average interference power. This interference power is found to be mutually uncorrelated among fingers and its average power is proportional to its instantaneous gain. The reason being that the interference power varies at the chip rate (MHz) while channel gain varies at the fading rate (hundreds of Hz). It is also found that the interference caused by non-orthogonality due to multi-path delays is same for all the fingers. This makes the optimum weights depend only on the channel impulse response and renders an easy way to obtain the optimum weights without actually measuring or estimating the interference power. In this paper, we show how the proportional scaling finger outputs can be performed based on a finger's own instantaneous channel gain. Therefore the new combining RAKE receiver is simply an MRC RAKE receiver with each finger's weight further scaled proportionally to the instantaneous channel gain. Compared with other optimum combining schemes, such as DMI or LMS the new scheme has much lower cost, does not have sample support problems and converges to MRC when there is no interference or the multi-paths have equal average power. Simulation results show that the proposed optimum combining RAKE receiver has a 0.3 dB to 2.5 dB gain over the MRC RAKE receiver.

A generalized optimum selection combiner selects an arbitrary number (m 2/spl les/m/spl les/L) of diversity branches with the largest signal-to-interference-plus-noise ratio (SINR) from a total of L available branches in the presence of co-channel interference (CCI), it weights and combines the selected branches to maximize the SINR for the desired user. A generalized optimum selection combiner is studied as opposed to the conventional optimum combiner, which combines all the available branches in order to achieve the best trade-off between the receiver performance and complexity in the presence of CCI. This paper presents a closed-form expression for the average SINR of this generalized optimum selection combiner for non-identical independent (non-i.i.d.) Rayleigh fading channels in the presence of one co-channel interferer. The presented SINR expression reduces to the average signal-to-noise (SNR) of a generalized diversity selection combiner with a diversity order of m when there is no co-channel interference. When the interference increases it asymptotically reduces to the average SNR of a generalized diversity selection combiner with a diversity order of m-1 as if there was no interference. The paper also derives for the multiple co-channel interferers, the trade-off between the interference cancellation and diversity gain improvement. Using a subspace approach, the paper shows that optimally combining m branches from available L branches in the presence of n co-channel interferers can eliminate n (n

A closed-form expression for the average signal-to-noise-ratio (SNR) of generalized diversity selection combining, using the m largest (in instantaneous SNR) diversity signals, for arbitrary m, assuming that the Rayleigh fading statistics on each diversity branch are identically, independently distributed (i.i.d.), already exists in the literature. In this paper, a similar closed-form expression, but for nonidentically distributed statistics, is derived, This expression specializes to known results, such as the average SNRs of maximal-ratio combining with either i.i.d. or non-i.i.d. diversity statistics and that of conventional selection combining (CSC) with i.i.d. diversity statistics. In addition, it provides, for the first time, a simple closed-form solution to the combined SNR of CSC with non-i.i.d. diversity statistics. Further, the closed-form solution for the SNR of selecting the m, largest diversity signals has negligible computational complexity.

In Kong and Milstein (1998) a simple closed form expression for the average signal-to-noise-ratio (SNR) of combining the m largest (in instantaneous SNR) diversity signals, for arbitrary m, assuming that the Rayleigh fading statistics on each diversity branch were identically independently distributed (iid), was found. In this paper, a similar closed form expression, but for non-identically distributed statistics, is derived. This expression not only specializes to the known results, such as the average SNRs of maximal ratio combining (MRC) with either iid or non-iid diversity statistics and that of conventional selection combining (CSC) with iid diversity statistics (Jakes 1974), but also provides, for the first time, a simple closed form solution to the combined SNR of the conventional selection combining with non-iid diversity statistics. Further, the closed form solution for the SNR of selecting the m largest diversity signals has negligible computational complexity.

It is well known that power control is critical in CDMA mobile systems. In this paper, the error probability of a multicell CDMA system, operating with imperfect power control over a frequency selective multipath fading channel, is derived. Asymptotic expressions (for high signal-to-interference-plus-noise ratios) of the error probability show that the use of diversity combining exacerbates the effect of the power control error (PCE), since the power control is identical on each diversity channel; also, the error probability increases exponentially with PCE, while (asymptotically) increasing linearly with the number of users and decreasing inverse linearly with the processing gain. In addition to the asymptotic results mentioned above, both Chernoff bounds on, and approximations to, the error probability are found. Numerical results reveal the tightness of the Chernoff bounds, and show that the approximations are actually much tighter than the bounds, at least for PCE standard deviations of 1.5 dB or less.

The average signal-to-noise-ratio (SNR) of a generalized selection combining (GSC) scheme, in which the m diversity branches (m/spl les/L, where L is the total number of diversity branches available) with the largest instantaneous SNRs are selected and coherently combined, is derived. A Rayleigh fading channel is assumed, and a simple closed-form expression for the SNR is found which is upper bounded by the average SNR of maximal ratio combining, and lower bounded by average SNR of conventional selection combining.

Based on the observation of Kim, Kwon, Hong and Whang (see ibid., vol.46, no.9, p.1109-10, 1998), we discovered that in our derivation (see ibid., vol.44, p.1117-29, 1996), a factor of one-half in the exponent of one of three exponentials was inadvertently dropped and this, in turn, affected two other equations.

Several methods of diversity combining for a Rayleigh-faded channel are evaluated and compared. The methods considered are, for coherent reception, maximal ratio combining (MRC), selection combining (SC), and a generalization of SC, whereby the two (three) signals with the two (three) largest amplitudes are coherently combined. We will call this method second (third) order SC, and denote it SC2 (SC3). Similar techniques are also investigated for noncoherent reception, with equal gain combining (EGC) replacing MRC, and noncoherent versions of SC2 and SC3. Numerical results indicate that SC2 and SC3 significantly enhances the bit-error rate (BER) performance relative to that achievable with SC, and under certain conditions approaches the performance achieved by MRC or EGG. The performance enhancement of SC2 and SC3 is especially noticable for noncoherent reception, where EGC is seen to provide the best performance only for low BER values. In fact, when the BER is 10/sup -3/ or greater, SC2 and SC3 performed comparably to EGG, and in some cases performed better than EGC.