Temporal and spatial combining for 5G mmWave small cells

This chapter proposes the combination of temporal processing through Rake combining based on direct sequence-spread spectrum (DS-SS), and multiple antenna beamforming or antenna spatial diversity as a possible physical layer access technique for fifth generation (5G) small cell base stations (SBS) operating in the millimetre wave (mmWave) frequencies. Unlike earlier works in the literature aimed at previous generation wireless, the use of the beamforming is presented as operating in the radio frequency (RF) domain, rather than the baseband domain, to minimise power expenditure as a more suitable method for 5G small cells. Some potential limitations associated with massive multiple input-multiple output (MIMO) for small cells are discussed relating to the likely limitation on available antennas and resultant beamwidth. Rather than relying, solely, on expensive and potentially power hungry massive MIMO (which in the case of a SBS for indoor use will be limited by a physically small form factor) the use of a limited number of antennas, complimented with Rake combining, or antenna diversity is given consideration for short distance indoor communications for both the SBS) and user equipment (UE). The proposal’s aim is twofold: to solve eroded path loss due to the effective antenna aperture reduction and to satisfy sensitivity to blockages and multipath dispersion in indoor, small coverage area base stations. Two candidate architectures are proposed. With higher data rates, more rigorous analysis of circuit power and its effect on energy efficiency (EE) is provided. A detailed investigation is provided into the likely design and signal processing requirements. Finally, the proposed architectures are compared to current fourth generation long term evolution (LTE) MIMO technologies for their anticipated power consumption and EE

Power consumption modeling in integrated optical-wireless access network

The access segments of both optical and wireless networks are well known for their domination over the network’s total power consumption. Therefore, the study on energy consumption particularly in integrated optical-wireless access networks is crucial as energy consumption issue is increasingly vital nowadays. Existing works to date largely addressed the physical characteristics of integrated devices and algorithms for layer 2 and layer 3, where the study in power consumption modeling was often ignored. Hence, this thesis focuses on developing a power consumption model for integrated optical-wireless access networks and investigates the energy efficiency of such networks. Gigabit Passive Optical Network (GPON) as the optical backhaul and Worldwide Interoperability Microwave Access (WiMAX) and Long-Term Evolution (LTE) with femtocell application for the wireless network are considered. First, the power consumption model of the integrated network involving Optical Line Terminal (OLT) and integration between Optical Network Unit (ONU) and Base Station (BS) known as Integrated ONU-BS (IOB) are developed. Then, the power consumption behavior of ONU under different traffic loads has been investigated to model the total power consumption of integrated access networks. An empirical approach has been proposed to characterize the power consumption of the ONU by using real GPON testbed and to develop the power consumption model of ONU based on experimental results. This is followed by the extensive analyses that have been conducted to investigate the impact of various parameters such as split ratio, Femtocell Base Station (FBS) cell range, broadcast factor, and modulation and coding scheme into the total network power consumption and energy efficiency. It has been observed that GPONLTE has the worst energy efficiency performance when compared to GPON-WiMAX, even though it offers the highest data rates. The study has been further extended by including energy saving aspects where sleep mode techniques have been applied (i.e. power shedding for the ONU and idle mode procedure for FBS) based on the user behavior from the traffic profile pattern in Cyberjaya municipal broadband access networks. The implementation of energy saving techniques have shown further significant improvement of 15% lower energy consumption for the integrated access network

A multi-criteria BS switching-off algorithm for 5G heterogeneous cellular networks with hybrid energy sources

International audienceIn this paper, we study Base Station (BS) switching-off and offloading for next generation 5G heterogeneous (macro/femto) networks supplied with hybrid energy sources. This type of network will form the basis of the high-data rate energy- efficient cellular networks in the years to come. A novel generalized multimetric algorithm is presented. Our proposal is conceived to operate in highly heterogeneous Radio Access Network (RAN) environments, as expected for 5G, where BSs with different characteristics of coverage, radio resources and power consumption coexist. The approach uses a set of metrics with a modifiable priority hierarchy in order to filter, sort and select the BS neighbors, which receive traffic during redistribution and offloading of the BSs to be put into sleep mode. In our analysis, we study the impact of BS power model trends for active, idle and sleep modes on the BS switching-off. We highlight how the continuous evolution of BS components and the introduction of renewable energy technologies play a significant role to be considered in the decision making. The multimetric approach proposed makes it possible to define and accomplish defined network performance goals by adding specific emphasis on aspects like QoS, energy savings or green equipment utilization

Temporal and spatial combining for 5G mmWave small cells

This chapter proposes the combination of temporal processing through Rake combining based on direct sequence-spread spectrum (DS-SS), and multiple antenna beamforming or antenna spatial diversity as a possible physical layer access technique for fifth generation (5G) small cell base stations (SBS) operating in the millimetre wave (mmWave) frequencies. Unlike earlier works in the literature aimed at previous generation wireless, the use of the beamforming is presented as operating in the radio frequency (RF) domain, rather than the baseband domain, to minimise power expenditure as a more suitable method for 5G small cells. Some potential limitations associated with massive multiple input-multiple output (MIMO) for small cells are discussed relating to the likely limitation on available antennas and resultant beamwidth. Rather than relying, solely, on expensive and potentially power hungry massive MIMO (which in the case of a SBS for indoor use will be limited by a physically small form factor) the use of a limited number of antennas, complimented with Rake combining, or antenna diversity is given consideration for short distance indoor communications for both the SBS) and user equipment (UE). The proposal’s aim is twofold: to solve eroded path loss due to the effective antenna aperture reduction and to satisfy sensitivity to blockages and multipath dispersion in indoor, small coverage area base stations. Two candidate architectures are proposed. With higher data rates, more rigorous analysis of circuit power and its effect on energy efficiency (EE) is provided. A detailed investigation is provided into the likely design and signal processing requirements. Finally, the proposed architectures are compared to current fourth generation long term evolution (LTE) MIMO technologies for their anticipated power consumption and EE

Fast Power and Energy Efficiency Analysis of FPGA-based Wireless Base-band Processing

Nowadays, demands for high performance keep on increasing in the wireless communication domain. This leads to a consistent rise of the complexity and designing such systems has become a challenging task. In this context, energy efficiency is considered as a key topic, especially for embedded systems in which design space is often very constrained. In this paper, a fast and accurate power estimation approach for FPGA-based hardware systems is applied to a typical wireless communication system. It aims at providing power estimates of complete systems prior to their implementations. This is made possible by using a dedicated library of high-level models that are representative of hardware IPs. Based on high-level simulations, design space exploration is made a lot faster and easier. The definition of a scenario and the monitoring of IP's time-activities facilitate the comparison of several domain-specific systems. The proposed approach and its benefits are demonstrated through a typical use case in the wireless communication domain.Comment: Presented at HIP3ES, 201