Byung Chang Chung

Mobile Data Offloading With Almost Blank Subframe in LTE-LAA and Wi-Fi Coexisting Networks Based on Coalition Game

The problem of spectrum scarcity has raised the prospect of coexisting network. For example, long-term evolution-licensed-assisted access (LTE-LAA & Wi-Fi) can operate in the same frequency band. However, interference between the two different radio access technologies can severely reduce the performances of both networks. To mitigate this interference, the concept of an almost blank subframe (ABS) has been proposed. However, because the LTE-LAA macrocell must remain silent, this provides no incentive for its throughput enhancement. In this letter, we propose a transaction between LTE-LAA and Wi-Fi using ABS together with offloading. We model a time-resource utility model by jointly considering the resource consumed for ABS and offloading, and then formulate a coalition game. To achieve the solution of a coalition game, we consider two fairness concepts: min-max and Shapley fairness. We then verify the performance of the proposed game using simulations. It is shown that the proposed game model can improve resource utilization through the joint use of ABS and offloading.

Alignment-free sequence comparison using joint frequency and position information of k-words

This paper proposes a novel alignment-free sequence comparison method to identify the genetic relationships of organisms with a high resolution. For an accurate comparison, both frequency and position information of k-words are obtained from genome sequences in the proposed alignment-free sequence comparison method. Using principal component analysis (PCA) and phylogeny analysis, we identify the classification performance of proposed method. Then, the phylogenetic trees of proposed and conventional schemes are compared with reliable reference tree.This paper proposes a novel alignment-free sequence comparison method to identify the genetic relationships of organisms with a high resolution. For an accurate comparison, both frequency and position information of k-words are obtained from genome sequences in the proposed alignment-free sequence comparison method. Using principal component analysis (PCA) and phylogeny analysis, we identify the classification performance of proposed method. Then, the phylogenetic trees of proposed and conventional schemes are compared with reliable reference tree.

Resource Partitioning in Heterogeneous Networks Based on Bargaining Theory

In heterogeneous networks, interference management is a crucial issue. Resource partitioning is one of the solution of enhanced intercell interference coordination (eICIC) in LTE-A. In this paper, we propose a bargaining-based resource partitioning. We model a net profit model considering service profit as well as operating expense, and analyze the Nash bargaining solution (NBS). For solving the NBS, we consider two algorithms: concurrent and sequential bargaining. In sequential bargaining, the NBS is dominated by a bargaining order. To mitigate this effect, we further study a bargaining power adaptation scheme. We verify the performance of the NBS and the bargaining power adaptation scheme by means of simulations. It is shown that proposed NBS can maintain fairness with little throughput degradation. Our results can be applied as a guideline for fair resource partitioning with economic efficiency.

Genome-based microorganism classification using coalition formulation game.

Genome-based microorganism classification is the one of interesting issues in microorganism taxonomy. However, the advance in sequencing technology requires a low-complex algorithm to process a great amount of bio sequence data. In this paper, we suggest a coalition formation game for microorganism classification, which can be implemented in distributed manner. We extract word frequency feature from microorganism sequences and formulate the coalition game model that considers the distance among word frequency features. Then, we propose a coalition formation algorithm for clustering microorganisms with feature similarity. The performance of proposed algorithm is compared with that of conventional schemes by means of an experiment. According to the result, we showed that the correctness of proposed distributed algorithm is similar to that of conventional centralized schemes.

A novel fault recovery scheme for reliability of femtocell networks

Femtocell network is widely used for providing high data rate. However, there are some doubts about the reliability of femto base stations (BSs). When a fault occurs in a femto BS, MSs belonging to the faulted femto BS should handover to other BSs. Handover to inappropriate BS may decrease network efficiency. To make a smooth handover procedure, the usage of a candidate BS list is suggested. The candidate BS list consists of the recommended BSs based on received signal strength and cell load. By using the candidate BS list, MSs in the faulted femto BS can minimize the damage of failure.