Thomas Chapman

Spatially dependent ACLR modelling

In a multi-antenna transmitter system, the effective combined signal in the air will consist of a combination of signals. These signals will for example experience different path loss and then be combined at the receiver location. This results in a combined signal that may be different than a conducted signal at the antenna port. This model was used to investigate by how much the over the air signal and conducted signal differ at various points in space. This paper describes the work done using measurements and modelling to compare conducted measurements and over the air measurements. The investigations, and results discussed in this paper are primarily focused on Adjacent Channel Leakage power Ratio and emissions.

From 3G to 4G: background and motivation of 3G evolution

This introductory chapter provides an overview of the research and standardization background behind today’s HSPA technologies. A review of WCDMA development and standardization is provided in order for the reader to understand the framework upon which the 3G specifications have been built. This is followed by an insight into the workings of the standardization organizations that relate to WCDMA and HSPA, in particular 3GPP and ITU. The motivations and constraints behind the continuing evolution of HSPA are reviewed. This provides the reader with a framework with which to understand the drivers and processes behind the evolution features described in Part III of the book. In addition, a brief insight into the spectrum allocations and availability for HSPA is given.

Overview of release 99 WCDMA

This chapter provides a brief overview of WCDMA release 99 to serve as a background to subsequent chapters. WCDMA is a versatile and highly flexible radio interface that can be configured to meet the requirements from a large number of services, but the focus for the description is the functionality commonly used to support packet-data transmissions. The goal of this description is to provide sufficient background to the underlying release 99 WCDMA specifications such that HSPA and the HSPA enhancements that are described in subsequent chapters can be seen in context.

Chapter 18 – HSPA system performance

The performance of HSPA is driven by a complex mix of aspects such as, among other things, traffic behaviors, connectivity states, user population and positions, propagation environment effects, algorithmic effects, operator policies, intercell and inter-UE interference, signaling error levels, reporting accuracies, and user behavior. These factors interact in a nontrivial manner. A proportion of the factors relate to human behavior. Thus, the performance of an HSPA deployment is never analytically predictable. Nonetheless, statistical analysis and simulation of system behavior is needed for understanding performance drivers and benchmarking improvements. To properly characterize HSPA performance in terms of capacity and user experience, it is necessary to model system behavior to some extent. In this context, the term “system” refers to the interaction of all factors that impact capacity and user experience. This chapter reviews the principles behind modeling HSPA performance, the factors that drive performance, and the performance observed when modeling typical deployments.

Chapter 8 – High-speed downlink packet access

The introduction of High-Speed Downlink Packet Access (HSDPA) in release 5 implied a major extension of the WCDMA radio interface, significantly enhancing the WCDMA downlink packet-data performance and capabilities in terms of higher peak data rate, reduced latency, and increased capacity. The enhancements were achieved through the introduction of several techniques, including higher-order modulation , rate control , channel-dependent scheduling , and hybrid-ARQ with soft combining . Some of the responsibility for managing radio resources was moved from the RNC to the Node B, in order to enable decisions relating to the air interface to be made closer to the interface and faster. HSDPA is the fundamental downlink building block of the subsequent HSPA evolution. Release 5 HSDPA is described in detail in this chapter, whereas enhancements that have followed in later releases are described in subsequent chapters.

Higher-order modulation

The digital modulation scheme determines how bits are mapped to the phase and amplitude of transmitted signals. Higher-order modulation, meaning that the modulation alphabet is extended to include additional signaling alternatives, allows more information bits to be conveyed per modulation symbol, thereby increasing the spectral efficiency and peak rate. The WCDMA/HSPA standard supports a variety of modulation schemes, both in uplink and downlink, facilitating a flexible and large dynamic range of possible transport block sizes and offering a good complement to spatial-multiplexing multiantenna techniques for increasing the peak rate. Modulation schemes have been added in different stages during the evolution from release 5 to release 11. This chapter provides a detailed overview of the modulation schemes themselves and associated support features, such as pilot boosting and constellation rearrangement.

Chapter 19 – Release 12 and Beyond

The 3GPP WCDMA standard has undergone continuous development since its beginning. Today, WCDMA/HSPA is a best-in-class voice solution with exceptional voice accessibility and retainability. In addition, HSPA provides an excellent access technology for mobile broadband, as it delivers high data rates and high cell-edge throughput—all of which enable good user experience across the entire network. HSPA continues to evolve and will do so for many years to come. HSPA evolution aims to increase network flexibility and capacity to meet growing smartphone traffic and secure voice and application coverage. This chapter provides an overview of features standardized during 3GPP release 12 and also describes areas considered for release 13.

Multi-flow transmission

Multi-flow transmission , also referred to as HSDPA multi-flow data transmission , was introduced in WCDMA release 11. It enables improved user experience for cell-edge UEs located in the soft or softer handover coverage region of two cells on the same carrier frequency by allowing HS-PDSCH to be scheduled from both cells. Such operation allows more scheduling opportunities for the network, aids system load balancing, and improves cell-edge throughputs. Multi-flow operation relies on simultaneous reception of up to four HS-DSCH transport channels in the CELL_DCH state on up to two frequencies, of which a maximum of two HS-DSCH transport channels may reside at the same frequency and belong either to same or different Node Bs. This chapter describes in detail the release 11 Multi-flow feature.

High-speed uplink packet access

High-Speed Uplink Packet Access (HSUPA), also known as Enhanced Uplink , was introduced in WCDMA release 6. It provides improvements in WCDMA uplink capabilities and performance in terms of higher data rates, reduced latency, and improved system capacity and is therefore a natural complement to HSDPA. Together, the two are commonly referred to as High-Speed Packet Access (HSPA). This chapter describes in detail release 6 HSUPA since HSUPA is the fundamental uplink building block of the subsequent HSPA evolution. Subsequent chapters then elaborate on the enhancements to the release 6 HSUPA framework that were introduced in later releases.

CDMA transmission principles

HSPA is built upon release 99 Wideband CDMA, which is a technology based on the concept of spread spectrum transmission. The spread spectrum technique emerged out of military research as a basis for communications that aim to flexibly multiplex multiple users and services and to provide robustness against external interference. This chapter reviews some of the basics of spread spectrum techniques and building blocks that are required for a successful communications link and develops a baseband transmitter model. Impacts of multipath radio propagation effects on spread spectrum signals are examined, together with a short overview of receiver equalization strategies.