Claes Tidestav

Downtilted Base Station Antennas - A Simulation Model Proposal and Impact on HSPA and LTE Performance

This paper proposes a low-complexity model for vertical antenna radiation patterns, e.g. for inclusion in system- level simulations. They can be seen as extensions to the horizontal radiation pattern model used in 3GPP simulation scenarios. The model is verified against and compared to predicted and measured data from real networks. The impact on system-level performance is also investigated. It is seen that using the proposed model, simulated geometry distributions and soft handover statistics closely matching those of real networks may be achieved. The analysis also concludes that many real networks have better cell isolation than what is modeled by the 3GPP antenna model. As a consequence, the horizontal radiation pattern model significantly under-estimates the system level performance in such networks. Furthermore, the proposed model is used to assess the LTE and HSPA system-level performance for realistic scenarios.

Energy Performance of 5G-NX Wireless Access Utilizing Massive Beamforming and an Ultra-Lean System Design

This paper presents the energy performance of a new radio access technology (RAT) component in 5G, here denoted as 5G-NX. The 5G-NX RAT encompasses massive beamforming and an ultra-lean design as two of its key technology components. The user throughput, resource utilization of the cells and daily average area power consumption are evaluated by means of system level simulations in an Asian city scenario, and the results are compared with a traditional LTE deployment using the same network layout. The simulation results indicate that the new 5G-NX system provides much better energy performance compared to LTE and this is primarily due to the ultra-lean design and the high beamforming gain that provides both longer and more efficient component sleep in the network. At expected traffic levels beyond 2020, 5G-NX is shown to decrease the network energy consumption by more than 50% while providing around 10 times more capacity.

Providing extreme mobile broadband using higher frequency bands, beamforming, and carrier aggregation

To meet future demands on user experience and traffic volumes, mobile networks need to evolve towards providing higher capacities and data rates. In this paper we investigate the feasibility of incorporating higher frequency bands (15 GHz) and beamforming to support this evolution. We see that using user-specific beamforming, the challenging propagation conditions at higher frequencies are mitigated and outdoor-in coverage is often possible. In places where 15 GHz coverage is not satisfactory, swift fallback to a lower frequency band is essential. This is seamlessly provided by carrier aggregation with a 2.6 GHz band. Together these components provide a ten-fold increase in capacity over a reference system operating only at 2.6 GHz.

System overview and performance evaluation of GERAN-the GSM/EDGE Radio Access Network

With the now finalized standardization of the first phase of the EDGE concept and its introduction of 8PSK modulation to support higher data rates, GPRS has evolved into a third generation (3G) mobile communication system. Within its second phase, EDGE will evolve further into being capable of supporting real-time packet data and thereby providing the full range of 3G services. By adopting the UMTS quality of service (QoS) concept, together with the development of new radio bearers, support of real-time packet data is accomplished and the GSM/EDGE Radio Access Network (GERAN) is created. This paper describes and evaluates GERAN with the focus on IP multimedia and the alignment with the UMTS QoS model.

Enhanced WCDMA Fingerprinting Localization Using OTDOA Positioning Measurements from LTE

The focus of this paper is on the convergence of positioning technology between the WCDMA and the LTE cellular systems. The emerging possibility to use multi-RAT positioning nodes can be exploited to mitigate the lack of a high-precision indoor OTDOA positioning method in WCDMA, which today limits the coverage of self-learning databases for fingerprinting positioning in this cellular system. The problem at hand is solved by use of measured high precision OTDOA positions of opportunity from LTE.

Uplink CoMP for HSPA

Uplink co-ordinated multipoint reception (UL CoMP) has received attention recently, especially for LTE Advanced, due to its promise of increasing spectral efficiency. In this paper, UL CoMP for HSPA networks is considered. UL CoMP for HSPA may be deployed without changes to the standard, and may be applied also for legacy UEs. Comparisons and contrasts of CoMP with conventional soft/soft handover are discussed as well as practical receiver structures incorporating antenna selection within the pool of antennas available in a CoMP cell. Radio resource management issues are discussed including mobility, power control, load control, and scheduling. It is concluded that UL CoMP requires only minimal changes to these algorithms. In a practical scenario, gains in cell-edge throughput of at least 118% and 144% are demonstrated for CoMP-3 and CoMP-6, respectively, for the case of full buffer traffic. The gains are even larger for the case of short files uploads where the conventional network suffers from the inability to exploit soft/softer handover due to latencies involved in updating a UEs active set.

Performance evaluation of activity-based uplink load estimates in WCDMA

Activity-based uplink load estimation is considered for WCDMA. By taking the user activity explicitly into account, the method is suitable for a scenario where services with very different activity levels use the same RAB. Scenarios with different mixes of email and MMS (multimedia messaging service) traffic are considered. Simulations indicate that the method provides good accuracy in situations where methods without activity estimation may overestimate the uplink load with about 3 dB.

Low rate voice bearers in the GSM/EDGE radio access network

With the use of the 8PSK modulation available in the GSM/EDGE radio access network (GERAN), adaptive multirate (AMR) voice can be supported with good speech quality using half-rate (HR) or even quarter-rate (QR) bearers. In this paper channel coding schemes for 8PSK HR are evaluated in terms of quality and capacity. System level simulations show that a capacity gain of 20% can be obtained with HR bearers as compared to the default full-rate bearers in a 1/3 reuse deployment. It is also shown that the introduction of QR bearers, together with an ideal adaptation mechanism, could lead to a capacity gain of up to about 90% in a 4/12 reuse pattern. However, dynamic system level simulations indicate that both measurement periods and intra-cell handover will limit the capacity gains estimated from the static system level simulations. The simulations also indicate that the maximum system capacity can not be increased by HR/QR adaptation.

On automatic establishment of relations in 5G radio networks

One of the first key self-organizing features introduced in LTE was Automatic Neighbor Relations (ANR), a function for automatically generating relations between radio network entities that is needed for many features such as active-mode mobility, load balancing and dual connectivity. Given the benefits of ANR in LTE, we foresee that procedures for relations establishment will be an important integrated part of 5G systems as well. Moreover, the new emerging technology components of 5G such as massive beamforming expand the scope of relations beyond the neighbor relations of LTE. In this paper, we give an overview of key 5G radio access components, discuss the need for different types of identifiers and relations, and comment on the impact from the ultra-lean design principle of 5G. The paper also discusses some possible procedures for automatic relation establishment in consideration of the specific 5G aspects.