Heat advection and forced convection in a lattice code–Implementation and geothermal applications

A three-dimensional thermo-hydro-mechanical numerical model has recently been enhanced with thermal capabilities to study the response of geothermal reservoirs to stimulation and production.In this paper,we present an effort to consider three relevant thermal mechanisms in an existing lattice code initially designed for hydraulic fracturing:a)thermal advection in the fluid;b)heat transfer by forced convection from the rock to the fluid;and c)accurate thermal conduction in the rock matrix considering the thermal boundary layer effect.A numerical implementation of the new coupled advection-forced convection logic as well as the coupling with the existing conduction logic in the commercial code XSite is summarized.The numerical solution is compared to analytical solutions for simple simulation cases.The new simulation capability is applied in a large-scale geothermal example to illustrate its performance.

Evaluation of Codebook Design Using SCMA Scheme Based on A_(n) and D_(n) Lattices

The sparse code multiple access(SCMA)scheme is a Non-Orthogonal Multiple Access(NOMA)type of scheme that is used to handle the uplink com-ponent of mobile communication in the current generation.A need of the 5G mobile network is the ability to handle more users.To accommodate this,the SCMA allows each user to deploy a variety of sub-carrier broadcasts,and several consumers may contribute to the same frequency using superposition coding.The SCMA approach,together with codebook design for each user,is used to improve channel efficiency through better management of the available spectrum.How-ever,developing a codebook with a greater number of value sets is still another challenge.With enhanced techniques of encoding and decoding for 5G networks,mapping the multidimensional constellations in the SCMA system plays a signif-icant role in improving the system performance and enhancing the overall system performance.The creation of a codebook utilizing the SCMA approach in con-junction with the lattice theory is suggested in this study.The prototype is shaped using a popular lattice,such as A n and D n,as the basis.Afterward,from the primary lattice constellation,the multidimensional complex mother constellation with the most noticeable variance in power is discovered.The lattice-based cod-ing is generated by combining the codebooks with the mother constellation,and the codes in the matrices are mapped by rotating the constellations in this context.The suggested technique,in conjunction with the investigation of novel SCMA codebook sets,provides improved performance in terms of Bit Error Rate(BER)and complexity with regard to Signal to Noise Ratio(SNR).Finally,the bit error rate is reduced for various SNRs during transmission in the channel.