Fractional Frequency Reuse Research Articles

Power management in green FFR-based heterogeneous cellular networks

The growth of mobile devices and their traffic volume make it necessary for mobile network operators to provide higher capacity. As traditional macrocell-based cellular networks could not support a massive number of mobile users, Heterogeneous Networks (HetNets) are welcomed as a coexistence of macro-cells and small-cells in 5G mobile networks. The main challenge of 5G HetNets is the management of co-tier and cross-tier interference. Fractional Frequency Reuse (FFR) is a suitable technique to mitigate the interference along with improving spectrum efficiency. On the other side, energy consumption has attracted much attention in 5G green cellular networks. Efficient power allocation and cell zooming/cell switch-off techniques are of the most important research directions in this area. However, the impact of cell zooming/switch-off on FFR-based HetNets has not been attended adequately. In this paper, a solution is presented which exploits dynamic adjustment of cell-center radius and efficient power allocation in FFR-based HetNets when conducting a cell switch-off/cell zooming. A heuristic algorithm is presented for cell-center radius adjustment problem. Also, for efficient power allocation, a multi-objective optimization problem is formulated and solved using NSGA-II algorithm Simulation results show that the proposed method reduces energy consumption compared to the baseline method and diminishes the overall interference in the system.

Throughput Analysis of Small Cell Networks Under D-TDD and FFR

Dynamic time-division duplex (D-TDD) has emerged as an effective solution to accommodate the unaligned downlink and uplink traffic in small cell networks. However, the flexibility of traffic configuration also introduces additional inter-cell interference. In this letter, we study the effectiveness of applying fractional frequency reuse (FFR) as an interference coordination technique for D-TDD small cell networks. We derive the analytical expressions of downlink and uplink mean packet throughput (MPT), then study a network parameter optimization problem to maximize MPT while guaranteeing each user's throughput. Numerical results corroborate the benefits of the proposed FFR-based D-TDD in terms of improving throughput.

Estimates of Alpha/Beta (α/β) Ratios for Individual Late Rectal Toxicity Endpoints: An Analysis of the CHHiP Trial

PurposeChanges in fraction size of external beam radiation therapy exert nonlinear effects on subsequent toxicity. Commonly described by the linear-quadratic model, fraction size sensitivity of normal tissues is expressed by the α/β ratio. We sought to study individual α/β ratios for different late rectal effects after prostate external beam radiation therapy.Methods and MaterialsThe CHHiP trial (ISRCTN97182923) randomized men with nonmetastatic prostate cancer 1:1:1 to 74 Gy/37 fractions (Fr), 60 Gy/20 Fr, or 57 Gy/19 Fr. Patients in the study had full dosimetric data and zero baseline toxicity. Toxicity scales were amalgamated to 6 bowel endpoints: bleeding, diarrhea, pain, proctitis, sphincter control, and stricture. Lyman-Kutcher-Burman models with or without equivalent dose in 2 Gy/Fr correction were log-likelihood fitted by endpoint, estimating α/β ratios. The α/β ratio estimate sensitivity was assessed using sequential inclusion of dose modifying factors (DMFs): age, diabetes, hypertension, inflammatory bowel or diverticular disease (IBD/diverticular), and hemorrhoids. 95% confidence intervals (CIs) were bootstrapped. Likelihood ratio testing of 632 estimator log-likelihoods compared the models.ResultsLate rectal α/β ratio estimates (without DMF) ranged from bleeding (G1 + α/β = 1.6 Gy; 95% CI, 0.9-2.5 Gy) to sphincter control (G1 + α/β = 3.1 Gy; 95% CI, 1.4-9.1 Gy). Bowel pain modelled poorly (α/β, 3.6 Gy; 95% CI, 0.0-840 Gy). Inclusion of IBD/diverticular disease as a DMF significantly improved fits for stool frequency G2+ (P = .00041) and proctitis G1+ (P = .00046). However, the α/β ratios were similar in these no-DMF versus DMF models for both stool frequency G2+ (α/β 2.7 Gy vs 2.5 Gy) and proctitis G1+ (α/β 2.7 Gy vs 2.6 Gy). Frequency-weighted averaging of endpoint α/β ratios produced: G1 + α/β ratio = 2.4 Gy; G2 + α/β ratio = 2.3 Gy.ConclusionsWe estimated α/β ratios for several common late adverse effects of rectal radiation therapy. When comparing dose-fractionation schedules, we suggest using late a rectal α/β ratio ≤ 3 Gy.

LTE Network Analysis in Frequency Reuse Recycling Techniques

In recent years, several researchers have embraced fractional frequency (FF) reuse as a strategy for resolving the inter-cell and co-channel interferences of adjacent cells (ICI, CCI) as the number of wireless networks grows. This technique is focused on the cell division of two parts, the inner and the outer, which enables multiple frequency bands to be assigned. The frequency advantages can be completely used in each inner zone, since there is no inter-cell disturbance for consumers in inner regions. According to this effective usage of the frequency spectrum available, FF will reduce the interruption of the channel and improve device efficiency. This manuscript presents a comprehensive study of different mechanisms to select the optimal FF scheme based on the user throughput. The analysis was conducted in order to obtain the optimal internal and external range for the cells as well as the optimal frequency distribution between the areas of the FR, Fractional Frequency Reuse 1 (FFR1) and Fractional Frequency Reuse 2 (FFR2) and evaluating their outputs and their number of users. In detail the overall consumer efficiency through the configured frequency distribution is analyzed. The FFR is a resource allocation technique that can effectively mitigate inter-cell interference (ICI) in LTE based HetNets and it is a promising solution. The proposal also employs high number sectors in a cell, low interference and good frequency reuse. The processes are tested by way of multiple modeling simulations.

An Analytical Model for a Sectored Cellular Network with Embedded Small Cells

In order to handle the huge amounts of data transmitted through hot spots and to increase cell coverage in buildings, this paper proposes a sectored cellular network with small cells (SCNSC) embedded in each sector. Two region types, sectors and variable-radius small cells are classified in an SCNSC macro cell. Because the system capacity is enhanced by using fractional frequency reuse (FFR), the overall channel bandwidth is divided into two or three frequency bands depending on whether the number of sectors in a macro cell is even or odd. For the purpose of topological evaluation on the proposed SCNSC, we build an analytical model using Markov chain theory. The performance measures include new-call blocking and handoff-call dropping probabilities, average waiting times, and normalized throughputs in each sector and its embedded small cell by varying mobile stations’ moving speeds, the number of sectors, and the radius size of an embedded small cell. From the evaluation results, it is demonstrated that adjusting either the number of sectors or the coverage of an embedded cell can satisfy different service demands.

Multi-Tier Variable Height UAV Networks: User Coverage and Throughput Optimization

Unmanned aerial vehicles (UAVs) are increasingly considered to act as base stations (BSs) for the future wireless networks. Some of the crucial UAV-assisted network design challenges are the network coverage, throughput, and energy efficiency. Therefore, fast, low-complexity, and efficient UAV placement and resource allocation strategies are imperative. This paper presents a novel variable height multi-UAV deployment strategy to exploit the 3D flexibility of UAVs as BSs. We propose a multi-tier variable height UAV-based network deployment and compare its performance with the state-of-the-art equal height deployment. Height optimization is performed to deliver energy efficiency and throughput maximization for each cell. The results show that our proposed method is more energy-efficient in a multi-cell UAV network than the most widely used height optimization method in the literature. In UAV networks, users at the cell edges can receive very poor signal-to-interference-plus-noise ratio (SINR) levels due to interfering UAVs. To cope with this problem, we adopt a fractional frequency reuse (FFR) scheme to compensate low SINR levels. We optimize the SINR threshold corresponding to each cell to maximize their spectral efficiency (SE), thereby improving the network’s area spectral efficiency (ASE). The numerical results show that the proposed deployments provide significant gains in coverage density, SINR coverage probability, rate coverage, and ASE compared to equal height benchmark scheme. As the number of UAVs increases, the number of tiers need to increase to preserve the rate coverage of the network. Moreover, the performance of the proposed variable height model is expected to converge to that of equal height cellular design for a large number of UAVs.

On the True Fractions of Repeating and Nonrepeating Fast Radio Burst Sources

Abstract Observationally, fast radio bursts (FRBs) can be divided into repeating and apparently nonrepeating (one-off) ones. It is unclear whether all FRBs repeat and whether there are genuine nonrepeating FRBs. We attempt to address these questions using Monte Carlo simulations. We define a parameter T c at which the accumulated number of nonrepeating sources becomes comparable to the total number of repeating sources, which is a good proxy to denote the intrinsic repeater fraction among FRBs. Assuming that both types of sources exist and their burst energies follow power-law distributions, we investigate how the observed repeater fraction evolves with time for different parameters. If the lifetime of repeaters is sufficiently long that the evolutionary effect can be neglected within the observational time span, unless T c → ∞ (i.e., there is no genuine nonrepeating FRB source), the observed repeater fraction should increase with time first, reach a peak, and then decline. The peak time T p and peak fraction F r,obs,p depend on T c and other repeating rate parameters. With the current data, we pose a lower limit T c > 0.1 day for reasonable parameter values. We predict that future continuous monitoring of FRBs with CHIME or similar wide-field radio telescopes would obtain an F r,obs less than 0.04. The detection of a smaller peak value F r,obs,p < 0.04 in the near future would disfavor the ansatz that “all FRB sources repeat.”

Managing the Interference for Down-Link in LTE Using Fractional Frequency Reuse

Long Term Evolution has developed a new radio technology called femtocell or Femto Base station, which is well-suited to improve cellular network capacity and mobile coverage to indoor user's areas. Providing additional capacity and coverage expansion through FBSs could lead to large interference in a cellular radio communication network. In this paper, we proposed an efficient resource allocation scheme based on Fraction Frequency Reuse (FFR) for interference mitigation, where the entire spectrum is shared among network entities. FFR mechanism aims to reduce co-tier and cross-tier downlink interferences by allocating non-overlapping sets of bands to the user equipment at different geographic locations. The main purpose of this work is to compare two main types of FFR schemes, respectively, Strict FFR and Soft Frequency Reuse with the proposed scheme. The three types of FFR schemes were explained and evaluated with Monte-Carlo simulation based on some performance metrics, namely, sum-rate, spectral efficiency, and outage probability. Simulation results showed that the impacts of the proposed scheme are significantly high in comparison with two other methods. The proposed scheme proved to enhance spectral efficiency, reduced the outage probability, and increased the sum rate for all the users.

Fractional Frequency Reuse with Enhanced Scheduling Strategies

Heterogeneous networks are used to meet both capacity and coverage demands in a cellular network. As the frequencies are reused due to the limited spectrum availability, there exists co-channel interference (CCI) between the high power and low power nodes in such networks apart from the CCI between high power nodes. Inter cell interference coordination (ICIC) is a big challenge towards heterogeneous network deployments since users located at the cell range expansion (CRE) area are more vulnerable to stronger interference caused by the signals from the high power nodes. To enhance capacity, achieve good user experience and improve spectral efficiency interference management techniques like fractional frequency reuse (FFR) with enhanced scheduling strategies and ICIC using expectation maximization algorithm are proposed to mitigate the effects of the CCI. The resource allocation in FFR is done for the users in the cell center (full reuse) and CRE (partial reuse) regions based on the optimum post processing signal to interference plus noise ratio threshold with different schedulers in the two regions. It is shown that a particular combination shows the best throughput performance for the proposed enhanced FFR scheme.

Outcomes after Normal Tissue-Adopted 5 Fraction (Fr) Stereotactic Body Radiotherapy (SBRT) for Extra-Cranial Oligometastases - A Prospective Study

Outcomes after Normal Tissue-Adopted 5 Fraction (Fr) Stereotactic Body Radiotherapy (SBRT) for Extra-Cranial Oligometastases - A Prospective Study

Hypofractionated sequential radiotherapy boost: a promising strategy in inoperable locally advanced pancreatic cancer patients.

To investigate the potential benefits of a hypofractionated radiotherapy boost (HRB) after chemotherapy (CT) and concomitant chemoradiotherapy (CRT) in locally advanced pancreatic cancer (LAPC) patients. Primary endpoints were early and late toxicity, local control (LC) and pain-free progression (PFP) assessment. Two-years overall survival (OS), metastasis-free survival (MFS) and disease-free survival (DFS) were secondary endpoints. Patients (pts) affected by unresectable non-metastatic LAPC, previously treated with CT and CRT in upfront or sandwich setting, were selected for sequential HRB. Total prescribed dose was 30Gy in 5 fractions (fr) to pancreatic primary lesion. Dose de-escalation was allowed in case of failure in respecting organs at risk constraints. Early and late toxicity were assessed according to CTCAE v.4.0 classification. The Kersh-Hazra scale was used for pain assessment. Local Control, PFP, MFS and DFS were calculated from the date of HRB to the date of relapse or the date of the last follow-up. Thirty-one pts affected by unresectable, non-metastatic LAPC were consecutively enrolled from November 2004 to October 2019. All pts completed the planned HRB. Total delivered dose varied according to duodenal dose constraint: 20Gy in 5 fr (N: 6; 19.4%), 20Gy in 4 fr (N: 5; 16.2%), 25Gy in 5 fr (N: 18; 58.0%) and 30Gy in 6 fr (N: 2; 6.4%). Early and late toxicity were assessed in all pts: no Grade 3 or 4 acute gastrointestinal toxicity and no late gastrointestinal complications occurred. Median LC was 19months (range 1-156) and 1- and 2-year PFP were 85% and 62.7%, respectively (median 28months; range 2-139). According to the Kersh-Hazra scale, four pts had a Grade 3 and four pts had a Grade 1 abdominal pain before HRB. At the last follow-up only 3/31 pts had residual Grade 1 abdominal pain.Median MFS was 18months (range 1-139). The 2-year OS after HRB was 57.4%, while 2-year OS from diagnosis was 77.3%. Treatment intensification with hypofractionated radiotherapy boost is well tolerated in pts affected by unresectable LAPC previously treated with CT/CRT. Its rates of local and pain control are encouraging, supporting its introduction in clinical practice. Timing, schedule and dose of HRB need to be further investigated to personalize therapy and optimize clinical advantages.

Interference Management for Different 5G Cellular Network Constructions

Due to the technology growth in the fifth Generation (5G) in the modern era, there is an urgent need for Ultra-Reliable Communications (URC). It is considered one of the novel features for 5G. The most obvious limitation that faces the URC is the interference which is severe at the cell edges. Hence, the use of the Interference Management (IM) techniques such as Fractional Frequency Reuse (FFR) and Soft Frequency Reuse (SFR) is most important to overcome the interference and make good use of URC. The previous studies focused on the analysis of FFR and SFR for either the regular (hexagonal) cellular network only or irregular (voronoi) cellular network. This paper introduces the FFR and SFR analysis for hybrid cellular network which is defined as a mixture that combines both of the regular and irregular cellular networks. So, in this paper, the FFR and SFR performance analysis would be carried out and compared for each of the regular, irregular and hybrid cellular networks in both downlink and uplink scenarios.

RAPTAP: a socio-inspired approach to resource allocation and interference management in dense small cells

Femto Cells offer higher data rates to users within closed spaces. Dense deployment of small cells is a characteristic of pre-5G/LTE-Advanced Pro (LTE-A Pro) networks and is a precursor to the future 5G cellular networks. Combined with a Frequency Reuse Factor (FRF) of one, the dense small cell systems result in high co-tier interference which is undesirable. High interference Optimized scheduling decisions and interference management techniques are required to guarantee certain minimum data rates to the users at the cell-edge and increase the overall throughput of the system. This work presents a centralized scheduling approach that mitigates the detrimental impact of interference, thereby maximizing the overall throughput of the system. In doing so, we make use of concepts from Social theory and incorporate these ideas in the solution design. The centralized approach uses optimized scheduling algorithm (RAPTA) which takes feedback from the indoor users of all Femtos as the input and formulates a Mixed Integer Non-Linear Programming (MINLP) problem. Thereafter, the MINLP problem is relaxed and its solution carries out the Resource Block allocation and ensures optimal power transmission for every allocated resource block in all Femtos. We implement the proposed OPT algorithm on top of Proportional Fair (PF) in the Vienna Simulator. Since the RAPTA is NP-Hard and takes a considerably long time to solve the MINLP problem, we derive from it a polynomial time Heuristic algorithm (RAPTAP) which performs Resource Block allocation and sub-optimal Power transmission quite close to the RAPTA algorithm in terms of performance. RAPTAP is a two-stage approach each of which is inspired by ideas from two different strands of Sociological theory. We demonstrate through experiments that the proposed RAPTA + PF achieves 60.67% improvement in the services offered to the mobile users when compared to the classic PF algorithm with Soft Fractional Frequency Reuse (SFFR) interference management technique in the built environment. The Socio-inspired RAPTAP performs almost as well as the RAPTA + PF algorithm, with only a marginal 4% drop in the overall system throughput as compared to the latter. Further, we evaluate the RAPTAP heuristic in scenarios involving mobile users and demonstrate 14.52% improvement when compared to classic PF algorithm with Fractional Frequency Reuse-Full Isolation (FFR-FI) interference management. Finally, we compare the proposed Socio-inspired RAPTAP + PF with two state-of-the-art algorithms, viz., a Genetic Algorithm approach to resource allocation (NSGA-UDN) and a recent work on LTE-Unlicensed (LTE-U) + PF. Proposed Socio-inspired solution outperforms the LTE-U + PF and NSGA-UDN by 28.26% and 31.41%, respectively, in terms of throughput.

Drumming Motor Sequence Training Induces Apparent Myelin Remodelling in Huntington's Disease: A Longitudinal Diffusion MRI and Quantitative Magnetization Transfer Study.

Background:Impaired myelination may contribute to Huntington’s disease (HD) pathogenesis.Objective:This study assessed differences in white matter (WM) microstructure between HD patients and controls, and tested whether drumming training stimulates WM remodelling in HD. Furthermore, it examined whether training-induced microstructural changes are related to improvements in motor and cognitive function.Methods:Participants undertook two months of drumming exercises. Working memory and executive function were assessed before and post-training. Changes in WM microstructure were investigated with diffusion tensor magnetic resonance imaging (DT-MRI)-based metrics, the restricted diffusion signal fraction (Fr) from the composite hindered and restricted model of diffusion (CHARMED) and the macromolecular proton fraction (MPF) from quantitative magnetization transfer (qMT) imaging. WM pathways linking putamen and supplementary motor areas (SMA-Putamen), and three segments of the corpus callosum (CCI, CCII, CCIII) were studied using deterministic tractography. Baseline MPF differences between patients and controls were assessed with tract-based spatial statistics.Results:MPF was reduced in the mid-section of the CC in HD subjects at baseline, while a significantly greater change in MPF was detected in HD patients relative to controls in the CCII, CCIII, and the right SMA-putamen post-training. Further, although patients improved their drumming and executive function performance, such improvements did not correlate with microstructural changes. Increased MPF suggests training-induced myelin changes in HD.Conclusion:Though only preliminary and based on a small sample size, these results suggest that tailored behavioural stimulation may lead to neural benefits in early HD, that could be exploited for delaying disease progression.

The role of palliative radiation therapy in treating pleural or peritoneal disseminated tumors: 22 cases and a review of the literature.

Local radiation therapy (RT) can provide pain relief and reduce bleeding resulting from pleural or peritoneal dissemination of primary tumors. However, the optimal RT exposure dose for such tumors is unclear and the response rate is unknown. In this study, we examined the effectiveness of palliative RT for pleural or peritoneal disseminated tumors to determine the optimal dose in these patients. The data of 22 patients with pleural- or peritoneal-disseminated tumors who were treated with local RT at our institution between 2011 and 2019 were retrospectively reviewed. Among these patients, 9 (40.9%) had pleural tumors, 13 (59.1%) had peritoneal tumors and 2 had tumors in the peritoneum and umbilicus. The most common primary tumors were lung (22.8%) and pancreatic cancer (18.2%). RT was mainly administered for pain alleviation (72.7%). Three patients (13.6%) received RT for hemostasis. Thirteen patients (59.1%) received a regimen of 30 Gy/10 fractions (fr), with the total dosage for all patients ranging from 27 to 56 Gy. No grade 2 or higher RT-related adverse events occurred. Three and four patients obtained complete and partial responses, respectively. The timing of the measurement of response to pain relief ranged from 0 to 232 (median, 21) days upon completion of RT. Overall response to pain relief occurred in nine of 16 patients (56.3%) with pain before RT. Hemostasis was confirmed in 2 of the 3 patients (66.7%) with bleeding before RT. Twelve of 20 (60%) patients with symptoms before RT responded to RT. Disease-specific survival (DSS) time after RT ranged from 1 to 656 (median, 106) days. Prompt palliative administration of RT to patients with advanced disease to alleviate pain from disseminated tumors may achieve therapeutic efficacy.

Combination of the W boson polarization measurements in top quark decays using ATLAS and CMS data at sqrt{s} = 8 TeV

The combination of measurements of the W boson polarization in top quark decays performed by the ATLAS and CMS collaborations is presented. The measurements are based on proton-proton collision data produced at the LHC at a centre-of-mass energy of 8 TeV, and corresponding to an integrated luminosity of about 20 fb−1 for each experiment. The measurements used events containing one lepton and having different jet multiplicities in the final state. The results are quoted as fractions of W bosons with longitudinal (F0), left-handed (FL), or right-handed (FR) polarizations. The resulting combined measurements of the polarization fractions are F0 = 0.693 ± 0.014 and FL = 0.315 ± 0.011. The fraction FR is calculated from the unitarity constraint to be FR = −0.008 ± 0.007. These results are in agreement with the standard model predictions at next-to-next-to-leading order in perturbative quantum chromodynamics and represent an improvement in precision of 25 (29)% for F0 (FL) with respect to the most precise single measurement. A limit on anomalous right-handed vector (VR), and left- and right-handed tensor (gL, gR) tWb couplings is set while fixing all others to their standard model values. The allowed regions are [−0.11, 0.16] for VR, [−0.08, 0.05] for gL, and [−0.04, 0.02] for gR, at 95% confidence level. Limits on the corresponding Wilson coefficients are also derived.

Enhanced fractional frequency reuse approach for interference mitigation in femtocell networks

Small cell networks are expected to heavily be deployed in wireless communication networks due to it ability to enhance signals quality and spectrum utilisation. However, interference is posing a major threat to wireless communication especially cellular femtocell networks whereby its performance is degraded in dense deployment areas. For this reason, an enhanced fractional frequency reuse approach is proposed in this paper to mitigate the interference in femtocell networks. This is achieved by dividing the service area and frequency into three regions and three sets whereby each set is allocated different frequency set. The femtocell location is later obtained and assigned frequency in accordance to the region. The proposed approach helps in reducing the interference, boost the signal to interference plus noise (SINR), and enhance the throughput.

An improved water-filling algorithm based on power allocation in network MIMO

Inter-Cell Interference (ICI) could affect the performance of the LTE-Advanced (LTE-A) system and can be evaluated according to the user’s Signal to Interference and Noise Ratio (SINR). Owing to this, the power and frequency allocation schemes can be utilized in order to attain an optimum trade-off within the obtained SINR and the resulting interference. In this study, power allocation was integrated into the Dynamic Fractional Frequency Reuse (DFFR) scheme and Network MIMO (NetMIMO) to reduce ICI and enhance the performance of LTE-A downlink. Moreover, this study focuses on the design and development of a novel power allocation algorithm, which is an extension to the previous Improved Water-Filling algorithm (IWF), namely, Low-Complexity Improved Water-Filling algorithm (LC-IWF). Results indicated a reduction in computations and enhancement in interference rejection performance in comparison to the existing algorithms by removing the Lagrange multiplier and water level. Moreover, simulation results revealed that the proposed algorithm enhances the throughput and fairness of up to 20% and 25%, respectively. Furthermore, the power consumption was reduced by 41% and the running time was 5–10 times faster than the IWF algorithm while attaining the best solution. The proposed power allocation algorithm provided a significant improvement in the performance of the NetMIMO LTE-A system, which can be extended for future 5G networks.

Dose Intensified Chemoradiation and Intraluminal Brachytherapy Improve Outcomes in Middle Third Carcinoma Esophagus: Experience from a Regional Cancer Center

Introduction Esophageal cancer is known for its poor outcome despite multimodality treatment. In this study, we report our experience with concurrent capecitabine-based chemoradiotherapy followed by intraluminal brachytherapy (ILBT) for middle third esophageal cancer. Materials and Methods Twenty patients of histology-proven middle third esophageal cancer were treated with 45 Gray (Gy)/25 fraction (fr) of external beam radiation on telecobalt using two-dimensional technique with concurrent cisplatin 40 mg/m2 weekly with five such cycles along with tablet capecitabine 825 mg/m2 twice daily for the first 2 weeks and last 2 weeks of radiotherapy. This was followed by ILBT of 4 Gy × 3 fr placed 1 week apart from a total biologically effective dose of 60 Gy. Patients were followed up with clinical examination and serial barium swallow to assess response and toxicity. Results Out of 20 patients, disease-free survival at 2 years was 60%. At 5 years, the actuarial survival was 47% with five patients alive and two patients lost to follow-up at 3 years. One patient had grade 3 toxicity in the form of tracheoesophageal fistula (5%). Two patients had distal failure. Two patients had second primary tumor in the upper aerodigestive tract at the end of 7 years. Conclusion A combination of chemotherapy with cisplatin and capecitabine given concurrently with radical radiation therapy followed by ILBT boost is a safe and feasible protocol in the treatment of carcinoma esophagus involving middle third of esophagus. The local control and survival are comparable to historical studies with minimal toxicity.

Fractional frequency reuse based frequency allocation for 5G HetNet using master–slave algorithm

Frequency allocation in small cell-based green heterogeneous mobile networks is a demanding research domain nowadays. Femtocells are the essential components of small cell networks. In this paper, we propose a low power micro-femtocell network using the master–slave algorithm. In the master–slave algorithm, the master node allocates work to the slave nodes. When a slave ends its task given by a master node, it informs the master node, and it is being assigned a new workload. Slave nodes do not communicate with each other. In our approach, the microcell is divided into three sectors, and each sector is further categorized into three regions: inner region, outer region, and most-outer region. Femtocells are allocated in these three regions. According to the duty cycle, several femtocells are chosen as master femtocells. The rest of the femtocells are assigned under the supervision of the master femtocells. These femtocells are referred to as slave femtocells. The master femtocells communicate with the microcell, and the slave femtocells communicate with the corresponding master femtocell. Frequency allocation for this micro-femtocell network is proposed based on Fractional Frequency Reuse (FFR). The power consumption, signal-to-interference-plus-noise ratio (SINR), and spectral efficiency for the proposed network are calculated. The simulation results exemplify that the proposed scheme reduces the power consumption of the network by approximately 44%–80% than the conventional heterogeneous network. The simulation results also demonstrate that the proposed network has better SINR and spectral efficiency than the existing micro-femtocell network. For experimental analysis, vector signal generator (VSG) and vector signal analyzer (VSA) are used. The experimental results also show that the proposed network is greener compared to the existing micro-femtocell network.