Coordinated Multi-Point (CoMP) systems appear as advanced promising strategies to improve user throughputs, especially in interference limited regions, at cell edge. Whether CoMP consists in jointly processing data from multiple transmission points, or in smartly coordinating the allocation of resources, CoMP implementation requires significant computation effort, signaling exchange that may impact the bandwidth limited back-hauling resources. To alleviate signaling and computation cost, the solution consists in partitioning the cells into coordinating sets. The study proposes a novel approach to cluster the cells into coordinated sets and to dynamically update it, based on data collected from the field. Clustering algorithm is based on spectral clustering and aims at grouping cells with high `similarity' between them. In the context of Dynamic Point Selection, users are dynamically switched from one cell to another one from the coordinating set, to take profit from macro diversity or load balancing gains. Similarity then captures the likelikood of switching, through a combined distance metric based on geometrical distance and Handover frequency. Analysis is carried out from data mining tools, with input data from the field, in the dense wireless network of Manhattan, in New York. Geographical Information System application completes the interpretation of clustering results, by displaying cluster maps, and proves the capability of clustering thanks to this approach.

As cellular networks like 4G LTE networks get more and more sophisticated, mobiles also measure and send enormous amount of mobile measurement data (in TBs/week/metropolitan) during every call and session. The mobile measurement records are saved in data center for further analysis and mining, however, these measurement records are not geo-tagged because the measurement procedures are implemented in mobile LTE stack. Geo-tagging (or localizing) the stored measurement record is a fundamental building block towards network analytics and troubleshooting since the measurement records contain rich information on call quality, latency, throughput, signal quality, error codes etc. In this work, our goal is to localize these mobile measurement records. Precisely, we answer the following question: what was the location of the mobile when it sent a given measurement record? We design and implement novel machine learning based algorithms to infer whether a mobile was outdoor and if so, it infers the latitude-longitude associated with the measurement record. The key technical challenge comes from the fact that measurement records do not contain sufficient information required for triangulation or RF fingerprinting based techniques to work by themselves. Experiments performed with real data sets from an operational 4G network in a major metropolitan show that, the median accuracy of our proposed solution is around 20 m for outdoor mobiles and outdoor classification accuracy is more than 98%.

LTE's uplink (UL) efficiency critically depends on how the interference across different cells is controlled. The unique characteristics of LTE's modulation and UL resource assignment poses considerable challenges in achieving this goal because most LTE deployments have 1:1 frequency reuse, and the uplink interference can vary considerably across successive time-slots. In this paper, we propose LeAP, a measurement data-driven machine learning paradigm for power control to manage uplink interference in LTE. The data-driven approach has the inherent advantage that the solution adapts based on network traffic, propagation, and network topology, which is increasingly heterogeneous with multiple cell-overlays. LeAP system design consists of the following components: 1) design of user equipment (UE) measurement statistics that are succinct, yet expressive enough to capture the network dynamics, and 2) design of two learning-based algorithms that use the reported measurements to set the power control parameters and optimize the network performance. LeAP is standards-compliant and can be implemented in a centralized self-organized networking (SON) server resource (cloud). We perform extensive evaluations using radio network plans from a real LTE network operational in a major metro area in the US. Our results show that, compared to existing approaches, LeAP provides$4.9\times$gain in the 20th percentile of user data rate,$3.25\times$gain in median data rate.

The success of LTE heterogeneous networks (HetNets) with macrocells and picocells critically depends on efficient spectrum sharing between high-power macros and low-power picos. Two important challenges in this context are: 1) determining the amount of radio resources that macrocells should offer to picocells, and 2) determining the association rules that decide which user equipments (UEs) should associate with picos. In this paper, we develop a novel algorithm to solve these two coupled problems in a joint manner. Our algorithm has provable guarantee, and furthermore, it accounts for network topology, traffic load, and macro-pico interference map. Our solution is standard compliant and can be implemented using the notion of Almost Blank Subframes (ABS) and Cell Selection Bias (CSB) proposed by LTE standards. We also show extensive evaluations using RF plan from a real network and discuss self-optimized networking (SON)-based enhanced inter-cell interference coordination (eICIC) implementation.

A novel hybrid OFDMA/CDMA multiple access system for uplink communications in evolving 4G wireless systems is developed. Specifically, a DFT-precoded CDMA technique is proposed for the CDMA part of the multiple access. We elaborate on different configurations of precoded CDMA operation, and develop advanced receiver techniques, using frequency-domain interference cancellation. Detailed simulation results showing the performance of this multiple access approach is presented. Finally, we describe how the proposed approach has been incorporated in the currently developing Ultra Mobile Broadband (UMB) system, which is an evolution from the cdma2000 evolution standards family.

We propose a promising multi-antenna scheme specifically suitable for hybrid code and time division multiplexed (CTDM) high speed shared channels commonly employed in 3GPP and 3GPP2 standards, such as HS-DPA, 1xEVDO (HDR), and 1xEVDV. The scheme is called phase sweep transmit diversity (PSTD) and was originally proposed for power controlled dedicated voice channels. PSTD is shown to provide the benefits of beamforming without the requirement for channel or weight information feedback from the receiver to the transmitter. We evaluate the benefits of PSTD for two antenna configurations: (a) the so-called BF-2V configuration that encompasses two closely-spaced (/spl lambda//2) vertically polarized antenna columns: (b) the so-called DIV-2V antenna configurations, in which the two antenna columns are widely-spaced (10-20 /spl lambda/). When compared to selection transmit diversity (STD) and the baseline case of a single antenna transmission, PSTD offers significant gains for low-tier mobility users. In addition, the closely spaced antenna configuration produces consistently higher sector throughput as compared to the widely spaced configuration.

The transition from second- to third-generation mobile systems and the evolution paths of the relevant radio/network configurations are driven by technical and market considerations. In fact, these are affecting the standardization and research process ongoing at the regional level (ETSI, ACTS Program, US Joint Technical Committee, Japanese ARIB) as well as the global level (ITU). The related discussion is becoming more and more meaningful for operators and manufacturers who are perceiving, on the one hand, the new perspectives associated with service, features, and bandwidth management evolution, and on the other hand, the great impact that such an evolution could have on the existing market scenario and system development plans. In addition, due to the widespread usage of GSM worldwide, this system should also be considered within the evolution scenarios toward third generation. This paper analyzes the situation emerging from the standards context, identifies some key characteristics associated with current proposals, and tries to define a possible third-generation systems architecture based on the most encouraging propositions, e.g., the separation of radio-dependent and independent functions and the integration with B-ISDN. The paper rationale and the identified solutions reflect the research activities within the ACTS project RAINBOW (radio access independent broad band on wireless), addressing architectural solutions for UMTS (universal mobile telecommunications system), the European developing standard for third-generation systems.

This paper presents an access-independent network architecture for supporting UMTS service capabilities. The approach is based on an enhanced B-ISDN core network with personal and terminal mobility provided by intelligent network techniques. A physical realization is presented, and the protocols corresponding to the physical interfaces are identified. Protocols are proposed for UMTS mobility and service support, and the impact on the B-UNI and IN interfaces is considered. Reflecting the vision of the ETSI global multimedia mobility (GMM) standardization framework, UMTS service support through non-UMTS access is considered. Consideration of DECT as a UMTS access technology leads to an interworking proposal that presents each DECT terminal to the core network in terms of UMTS functional entities. Access-independent usage of UMTS terminal applications motivates additional interworking in the terminal to encapsulate the access network. The desirability of an access-independent UMTS application programming interface in the terminal is indicated.