Future LTE Research Articles

Deep Learning-Based Prediction of Resource Block Usage Rate for Spectrum Saturation Diagnosis

Strict restrictions on spectrum utilization and the rapid increases in mobile users have brought fundamental challenges for mobile network operators in securing sufficient spectrum resources. In designing reliable cellular networks, it is essential to predict spectrum saturation events in the future by analyzing the past behavior of base stations, especially their frequency resource block (RB) utilization states. This paper investigates a deep learning-based forecasting strategy of the future RB usage rate (RBUR) status of hundreds of LTE base stations deployed in Seoul, South Korea. The dataset consists of real measurement RBUR samples with a randomly varying number of base stations at each measurement time. This poses a difficulty in handling variable-length RBUR data vectors, which is not trivial for state-of-the-art deep learning estimation models, e.g., recurrent neural networks (RNNs), developed for handling fixed-length inputs. To this end, we propose a two-step RBUR estimation approach. In the first step, we extract a useful feature of the RBUR dataset that accurately approximates the behavior of the top quantile base stations. The feature parameters are carefully designed to be fixed-length vectors regardless of the dimensions of the raw RBUR samples. The fixed-length feature parameter vectors are readily exploited as the training dataset of RNN-based prediction models. Thus, in the second step, we propose a feature estimation strategy where the RNN is trained to predict the future RBUR from the input feature parameter sequences. With the estimated RBUR at hand, we can easily predict the spectrum saturation of the future LTE systems by examining the resource utilization states of the top quantile base stations. Numerical results demonstrate the performance of the proposed RBUR estimation methods with the real measurement dataset.

Quantitative Comparison of the Efficiency and Scalability of the Current and Future LTE Network Architectures

The core architecture of current mobile networks does not scale well to cope with future traffic demands owing to its highly centralized composition. Typically, it is believed that decentralization of the network architecture would be a sustainable approach to deal with ever growing amount of mobile data traffic. Nevertheless, the decentralization strategy of network architecture has not been properly examined through quantitative performance studies. Given that LTE will be the leading mobile networking technology in the coming 5–10 years, we conduct a hybrid study model to compare performance of current and future (decentralized) LTE network architectures. Particularly, our analysis presents numerical results quantifying impact of the number of attached nodes on the load at network routers and links, on the latency, and on the processing cost of the user’s data and control planes. Analytical results demonstrate that decentralization of the LTE network architecture achieves higher performance compared to the current architecture and improves the latency and cost of data packet delivery more than 10 and 6 times, respectively. Furthermore, it is also observed that GTP outperforms PMIP for all studied performance metrics in the decentralized architecture and provides about twofold better latency and cost for data packet delivery and roughly 6 times lower data traffic load on the network routers.

A Multi-Service Oriented Multiple Access Scheme for M2M Support in Future LTE

We propose a novel multiple access technique to overcome the shortcomings of the current proposals for the future releases of LTE. We provide a unified radio access system that efficiently and flexibly integrates both traditional cellular services and M2M connections arising from IoT applications. The proposed solution, referred to as MOMA, is based on establishing separate classes of users using relevant criteria that go beyond the simple handheld-IoT device split; service-dependent hierarchical spreading of the data signals; and a mix of multiuser and single-user detection schemes at the receiver. Signal spreading in MOMA allows densely connected devices with different QoS profiles to be handled, and at the same time its flexible receiver structure allows the receiver computational resources to be allocated to the connections that need them most. This yields scalable and efficient use of the available radio resources and better service integration. While providing significant advantages for key future communications scenarios, MOMA can be incorporated into LTE with a limited impact on the protocol structure and the signaling overhead.

Parameterized indoor propagation model for mobile communication links

ABSTRACTIn this letter, a path loss indoor propagation model is parameterized. This model is suitable for application in 4G and wireless networks and maybe applied in both LTE and LTE‐A system level simulators. Measurements were conducted at the most popular frequencies for future LTE networks of 1800 and 2600 MHz. In addition, path loss has been examined in terms of various antenna aspects such as polarization and directivity. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:823–826, 2016

Dynamic spectrum access in LTE-advanced networks

As early as 2014, mobile network operators’ spectral capacity will be overwhelmed by the demand brought on by new devices and applications. To augment capacity and meet this demand, operators may choose to deploy a Dynamic Spectrum Access (DSA) overlay. The signaling and functionality required by such an overlay have not yet been fully considered in the architecture of the planned Long Term Evolution Advanced (LTE+) networks. This paper presents a Spectrum Accountability framework to be integrated into LTE+ architectures, defining specific element functionality, protocol interfaces, and signaling flow diagrams required to enforce the rights and responsibilities of primary and secondary users. We also quantify, through integer programs, the benefits of using DSA channels to augment capacity under a scenario in which the LTE+ network can opportunistically use TV and GSM spectra. The framework proposed here may serve as a guide in the development of future LTE+ network standards that account for DSA.

LTE Femtocells: System Design and Performance Analysis

In this paper we consider a heterogeneous LTE network where femto cells are randomly deployed in a macro network. Femto cells are modeled as closed cells, namely only group member UEs can be associated with the femto cells. We demonstrate that inter-cell interference may prevent reliable operations for non-member UEs that are in proximity of a closed cell, which thus experience outage. We show how some of the novel features introduced in the Rel-10 specifications of the LTE standard can be leveraged by a suitable inter-cell interference coordination scheme (ICIC), which relies upon resource partitioning among different nodes to reduce the inter-cell interference problem. Additional significant improvements can be achieved when the proposed ICIC scheme is associated to a simple yet effective autonomous power control algorithm, described in detail in the paper, and further gains are demonstrated for UEs employing interference cancellation of broadcast interfering signals. We finally propose an enhanced ICIC method, based on a tighter coordination between macro and femto nodes, whose significant performance improvements advocate for suitable updates to the future LTE specifications.

Radio Interface Technologies for Cooperative Transmission in 3GPP LTE-Advanced

This paper presents an overview of radio interface technologies for cooperative transmission in 3GPP LTE-Advanced, i.e., coordinated multi-point (CoMP) transmission, enhanced inter-cell interference coordination (eICIC) for heterogeneous deployments, and relay transmission techniques. This paper covers not only the technical components in the 3GPP specifications that have already been released, but also those that were discussed in the Study Item phase of LTE-Advanced, and those that are currently being discussed in 3GPP for potential specification in future LTE releases.

Evaluation of an Interference-Coordination Algorithm Based on Self-Organizing Techniques on a Real LTE Deployment Scenario

An implementation of an inter-cell interference control algorithm in a LTE network is presented. The proposed procedure takes advantage of collaborative self-organizing functions among neighbouring cells to improve the performance of conventional ICIC (Inter-Cell Interference Coordination) algorithms. In particular, the sharing of resource occupation information between adjacent cells is exploited to coordinate resource allocation for users. The proposed algorithm has been tested on a link-level simulator using a physical layer abstraction based on data from a real network scenario. Both deployment and traffic data is used, so the technique is tested beyond canonical implementations and results can be considered as more realistic. Results show an enhancement in Signal-to-Interference ratio (SINR) and throughput for cell-edge users compared to similar procedures not based on self-organizing techniques. In addition, a decrease in the blocking probability for those users far away from base station has been observed. Finally, the quality of service for users close to cell centre remains unchanged, and in some cases, becomes improved. These effects are more notorious in medium-loaded situations, especially in unb//alancedtraffic cases. These results support the feasibility of the implementation of this procedure for future LTE deployments.