Positioning in LTE

When a mobile operator migrates its network from the third generation (3G) system to Long Term Evolution (LTE), both 3G and LTE will coexist for a period of time. Since the 3G circuit-switched (CS) voice mechanism is more mature and available than that for the LTE Voice over Internet Protocol (VoIP), the operator may consider CS fallback (CSFB) as a solution for providing reliable voice calls. According to the 3G Partnership Project (3GPP) CSFB procedure, when a mobile user in the LTE network has an incoming or an outgoing call, the user equipment (UE) falls back from LTE to Universal Mobile Telecommunications System (UMTS). When the call is complete and released, the UE immediately returns to LTE. If the next activity for the UE is another voice call, immediately switching from UMTS to LTE may not be efficient. In this case, the UE has to perform another CSFB. To resolve this issue, we suggest delaying the returns to avoid unnecessary CSFBs, which is called delayed return (DR). Based on the measurements from the real UMTS and LTE networks, we develop an analytic model for investigating the performance of the CSFB with DR. This paper indicates that the DR scheme can effectively reduce the CSFB costs by up to 60%.

The recent wireless communication networks rely on the new technology named Long Term Evolution (LTE) to offer high data rate real-time (RT) traffic with better Quality of Service (QoS) for the increasing demand of customer requirement. LTE provide low latency for real-time services with high throughput, with the help of two-level packet retransmission. Hybrid Automatic Repeat Request (HARQ) retransmission at the Medium Access Control (MAC) layer of LTE networks achieves error-free data transmission. The performance of the LTE networks mainly depends on how effectively this HARQ adopted in the latest communication standard, Universal Mobile Telecommunication System (UMTS). The major challenge in LTE is to balance QoS and fairness among the users. Hence, it is very essential to design a down link scheduling scheme to get the expected service quality to the customers and to utilize the system resources efficiently. This paper provides a comprehensive literature review of LTE MAC layer and six types of QoS/Channel-aware downlink scheduling algorithms designed for this purpose. The contributions of this paper are to identify the gap of knowledge in the downlink scheduling procedure and to point out the future research direction. Based on the comparative study of algorithms taken for the review, this paper is concluded that the EXP Rule scheduler is most suited for LTE networks due to its characteristics of less Packet Loss Ratio (PLR), less Packet Delay (PD), high throughput, fairness and spectral efficiency.

This paper discusses about feasibility of common wireless communication services recognition concept for three different standards, i.e. global system for mobile communications (GSM), universal mobile telecommunications system (UMTS) or wideband code division multiple access (WCDMA), and long term evolution (LTE). They are in mobile telecommunication field also known well as 2G, 3G, and 3.9G respectively. In the term of cognitive system to recognize these three standard services, we investigate the initialization procedure and downlink signal structure as an important keys. As a result, there is big possibility to develop a common wireless communication services recognition for GSM, UMTS and LTE through a concept of synchronization channel detection.

Wireless Local Area Network (WLAN) offloading is an important approach to address the data traffic challenge faced by Long Term Evolution (LTE) network. Legacy offloading solutions based on the core network suffer from the limitations of load unbalance and user experience degradation. To solve this problem, 3GPP has recently proposed a radio access network (RAN) assisted WLAN offloading scheme. In this article, we thoroughly analyze the performance of this new scheme, with emphasis on the RAN auxiliary parameters and control rules defined in it. Furthermore, two kinds of offloading algorithms based on this scheme are proposed and compared with the traditional solutions by simulation. Results show that the RAN-assisted offloading scheme can increase average user throughput and leverage resources available in both LTE and WLAN systems.

Future Long Term Evolution (LTE) Radio Access Network (RAN) will benefit from a significant degree of self-organization. Autonomic Load Balancing (ALB) is considered as an important self-organizing function in LTE RAN. In this work, distributed ALB is achieved by Autonomic Network Management (ANM). Load conditions of eNBs (E-UTRAN NodeB) can be detected. Sizes and shapes of cellular coverage can be adjusted automatically according to load conditions, so as to balance load. Simulation results demonstrated that by the use of ALB, the system capacity can be improved significantly.

Commoditization and virtualization of wireless networks are changing the economics of mobile networks to help network providers, e.g. Mobile Network Operators (MNOs), Mobile Virtual Network Operator (MVNO), move from proprietary and bespoke hardware and software platforms to an open, cost-efficient and flexible cellular ecosystem. In addition, rich and innovation local services can be efficiently materialized through cloudification by leveraging the existing infrastructure. The future communication architecture for mobile cloud services - Mobile Cloud Networking (MCN) is a EU FP7 large-scale integrating project (IP) funded by the European Commission that is focusing on how cloud computing and network function virtualization concepts are applied to achieve virtualization of cellular networks. It aims at the development of a fully cloud-based mobile communication and application platform, or more specifically, it aims to investigate, implement and evaluate the technological foundations for the mobile communication system of long-term evolution (LTE), based on mobile network with decentralized computing and smart storage offered as one atomic service: on-demand, elastic and pay-as-you-go. MCN will investigate, implement and evaluate the technological foundations for that system to meet real-time performance and support efficient and elastic use and sharing of radio access and mobile core network resources between operators. Mobile network functionalities-such as baseband unit processing, mobility management and quality of service (QoS) control-will run on the enhanced mobile cloud platform leveraging commodity hardware, which requires extensions toward higher decentralization and enhancing them to elastically scale up and down based on load. The end-to-end control and management orchestrates infrastructure and services across several technological domains: wireless, mobile core and data centres, providing guaranteed multiple end-to-end service, mobility through the Follow-Me Cloud concept. In this chapter, we present three enabling components of such a future MCN architecture: Radio Access Network as a Service (RANaaS), Information-Centric Networking as a Service (ICNaaS) and Mobility Prediction as a Service (MOBaaS).

In the current environment of burgeoning demand for mobile broadband, Long Term Evolution (LTE) is the most preferred wireless technology for the mobile operators. Considering the legacy multi-technology networks, operators need to strategically work upon maximizing their revenue while minimizing their cost and satisfying the subscriber’s requirements as well. Operators have a choice between 2 network strategies- LTE overlay and single radio access network (SRAN). A survey carried out proved SRAN to be the optimum LTE deployment strategy considering the total cost of ownership (TCO). This paper discusses the effect on the system performance due to the up gradation of network from second generation (2G) to third generation (3G) to long term evolution (LTE) systems using Nokia Siemens Network Flexi multi-radio base stations. Measurements of RSRP (Reference Signal Received Power), SINR (Signal to Interference plus Noise Ratio) and throughput were carried out by a drive test within 2Km of the deployed site area which indicated that all the 3 parameters were affected as the user equipment moved away from the site area and towards the cell edges. This problem can be addressed by deployment of low power relay nodes, one of the promising techniques, for increasing the coverage of LTE advanced networks (the future of LTE systems).

Long Term Evolution (LTE) is the new upgrade path for carrier with both GSM/UMTS networks and CDMA2000 networks. The LTE is targeting to become the first global mobile phone standard regardless of the different LTE frequencies and bands use in other countries barrier. Adaptive Modulation and Coding (AMC) is used to increase the network capacity or downlink data rates. Various modulation types are discussed such as Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM). Spatial multiplexing techniques for 4×4 MIMO antenna configuration is studied. With channel station information feedback from the mobile receiver to the base station transmitter, adaptive modulation and coding can be applied to adapt to the mobile wireless channels condition to increase spectral efficiencies without increasing bit error rate in noisy channels. In High-Speed Downlink Packet Access (HSDPA) in Universal Mobile Telecommunications System (UMTS), AMC can be used to choose modulation types and forward error correction (FEC) coding rate.

The rapid evolution of 3G technology demands an adaptive, robust network management system. In the 3G UMTS (Universal Mobile Telecommunications System) system, a new radio access network (RAN) called UTRAN (UMTS terrestrial radio access network) is introduced based on W-CDMA (instead of TDMA/FDMA) air interface transmission. The normal network management functionality needs to be supported that is, fault configuration, accounting, performance and security management (FCAPS). The network resource model for UMTS is defined by 3GPP [1] and is object oriented Output data for bulk configuration has a standard XML format defined by the 3GPP. By applying standard software engineering techniques for exporting XML from a relational database we demonstrate that using a relational database for storing management data can achieve very good performance for bulk configuration management export.

Long Term Evolution (LTE) of UMTS Terrestrial Radio Access and Radio Access Network is a Fourth Generation wireless broadband technology which is capable of providing backward compatibility with 2G (Second Generation) and 3G (Third Generation) technologies. LTE is able to deliver high data rate and low latency with reduced cost. It uses the frame structure as Time Division Duplexing (TDD) Land Frequency Division Duplexing (FDD). The broadcast channel in LTE is Physical Broadcast Channel (PBCH) information is divided into two categories one is Master Information Block (MIB) consists of a limited number of the most frequently transmitted parameters essential for initial access to the cell, and is carried on the PBCH and the other System Information Blocks (SIB) at the physical layer are multiplexed together with unicast data transmitted. The main objective of this paper is the realization of receiver architectures for PBCH in LTE considering Single Input Single Output (SISO), Multiple Input Single Output (MISO), Single Input Multi Output (SIMO), and Multiple Input Multiple Output (MIMO). The Receiver processing steps involves as channel de-estimation, demodulation, minimum mean square error (MMSE) and among the received data minimum value is calculated using the comparator at receiver side. By applying the following VLSI DSP methods folding to reduce the number of resource elements required and another method consider to reduce the delay is Super scalar processing method and the results are compared between the direct method, folding method and super scalar method. Based on simulation and implementation, results are discussed in terms of Register Transfer Level (RTL) design, Field Programmable Gate Arrays (FPGA) editor, power estimation and resource estimation. To simulate all the modules of all PBCH channel Verilog code, Modelsim is used. For synthesis and implementation of the above architecture PlanAhead 13.4 tool on Virtex-5, xc5vlx50tff1136-1 device board is used.

This paper presents an automatic approach for the detection of high interference and low coverage scenarios (overshooting and pilot pollution) in Universal Mobile Telecommunications System (UMTS) /Long Term Evolution (LTE) networks. These algorithms, based on periodically extracted Drive Test (DT) measurements (or network trace information), identify the problematic cluster locations for each evaluated cell and compute harshness metrics, at cluster and cell level, quantifying the extent of the problem. The cluster based detection associated with an auto-correlation distance for shadow fading, enables to detect prevailing under performance areas and mitigate detections caused by the radio channel variability. Future work is in motion by adding self-optimization capabilities to the algorithms, which will automatically suggest physical and parameter optimization actions. The proposed algorithms were validated for a live network in both rural and urban scenarios. A total of 173 4\(^{th}\) Generation (4G) cells were self-diagnosed and performance metrics were computed. The most negative sub-performance scenarios concern high interference control in urban environment and low coverage in rural environment.

The power consumption of wireless access networks will become an important issue in the coming years. In this study, the power consumption of base stations for mobile WiMAX (Worldwide Interoperability for Microwave Access), fixed WiMAX, UMTS (Universal Mobile Telecommunications System), HSPA (High-Speed Packet Access) and LTE (Long-Term Evolution) is modelled and related to the coverage. A new metric, the power consumption per covered area PC(area), is introduced, to compare the energy efficiency of the considered technologies for a basic reference configuration and a future extended configuration, which makes use of novel Multiple Input Multiple Output (MIMO) technology. The introduction of MIMO has a positive influence on the energy efficiency: for example, for a 4 x 4 MIMO system, PC(area) decreases with 63% for mobile WiMAX and with 50% for HSPA and LTE, compared to a Single Input Single Ouptut (SISO) system. However, a higher MIMO array size (i.e. a higher number of transmitting and receiving antennas) does not always result in a higher energy efficiency gain.

Radar interference into LTE base stations in the 3.5 GHz band

The fifth-generation (5G) mobile network is facing severe challenges of the traffic demand surge and spectrum scarcity. To improve the network capacity and data rate, the deployment of Long Term Evolution (LTE) cellular system on unlicensed band is considered as one of the promising solutions. But the interference problem among LTE and WiFi system on the same unlicensed band hinders the deployment process, which is a critical issue unsolved for network operators. Therefore, a novel channel access scheme integrating the energy detection scheme and back-off mechanism in LTE system has been proposed in this paper, to minimize the interference to WiFi system. The throughput of both LTE and WiFi systems and the optimal sensing time and back-off time are theoretically analyzed with proofs. Furthermore, an efficient adaptive reconfiguration strategy of access parameters is proposed based on the channel occupancy cognition results. Simulation results verify that the proposed channel access scheme with optimal back-off time can double the throughput of WiFi system when coexisting with LTE system on unlicensed band.

The number of connected devices and the amount of data traffic exchanged through mobile networks is expected to double in the near future. Long Term Evolution (LTE) and fifth generation (5G) technologies are evolving to support the increased volume, variety and velocity of data and new interfaces the Internet of Things demands. 5G goes beyond increasing data throughput, providing broader coverage and reliable ultra-low latency channels to support challenging future applications. However, this comes with a cost. As such, the architectural design of radio access network requires due consideration. This chapter explains why the radio access network is critical to 5G success and how novel trends on edge computing, network slicing and network virtualisation perform a critical role in optimising resources on emerging 5G infrastructures.