0000000000433381
AUTHOR
Ilmari Repo
showing 8 related works from this author
Analysis of VoIP over HSDPA Performance with Discontinuous Reception Cycles
2009
The aim of this paper is to evaluate how Discontinuous Reception (DRX) cycles and related timers take effect to Voice over IP (VoIP) performance when High Speed Downlink Packet Access (HSDPA) networks are in question. DRX cycles limit the scheduling freedom of users and increase battery saving opportunities in the User Equipment (UE) by allowing it to turn its receiver circuitry off for some periods of time. Prior work has concentrated mainly on optimizing the usage of radio resources when small bit rate delay critical services, like VoIP, are considered. However, the battery life of small handheld devices might become a limiting factor in providing satisfactory user experience. Thus, this …
Cognitive self-healing system for future mobile networks
2015
This paper introduces a framework and implementation of a cognitive self-healing system for fault detection and compensation in future mobile networks. Performance monitoring for failure identification is based on anomaly analysis, which is a combination of the nearest neighbor anomaly scoring and statistical profiling. Case-based reasoning algorithm is used for cognitive self-healing of the detected faulty cells. Validation environment is Long Term Evolution (LTE) mobile system simulated with Network Simulator 3 (ns-3) [1, 2]. Results demonstrate that cognitive approach is efficient for compensation of cell outages and is capable to improve network coverage. Anomaly analysis can be used fo…
Benchmarking of VoIP over HSDPA and LTE performance with realistic network data
2010
The purpose of this paper is benchmark the performance of voice over IP in high speed downlink packet access and in long term evolution networks. Benchmarking is conducted in homogeneous and heterogeneous scenario layouts assuming realistic propagation data generated over Tokyo map. Tools used in this paper are two fully dynamic time driven system simulators which have been used to support 3GPP standardization work. This benchmarking study provides insights to what e.g. different radio access technologies, scheduling mechanisms and receivers do for the performance of voice over IP. This paper indicated in various scenarios that long term evolution can offer higher performance for voice over…
Non-regular network performance comparison between HSDPA and LTE
2010
In this paper we study and benchmark the performance of 3rd Generation Partnership Project (3GPP) High Speed Downlink Packet Access (HSDPA) and 3GPP Long Term Evolution (LTE) Downlink with constant bit rate type traffic. In addition a non-regular simulation scenario is considered using realistic propagation data and base station positions related to Tokyo city downtown area. HSDPA was introduced in 3GPP Release 5 and in further releases the technology has been improved with e.g. receive and transmit diversity technologies and support for higher order modulation schemes. LTE was introduced in 3GPP Release 8 with completely new physical layer and improved Radio Resource Management (RRM) funct…
Enhancing HSUPA system level performance with dual carrier capability
2010
The purpose of this paper is to analyze how dual carrier capability can enhance High Speed Uplink Packet Access performance in comparison to using only single carrier. Dual carrier operation gives the User Equipment the possibility to transmit simultaneously using two 5 MHz bands, theoretically doubling the peak data rates and user throughput. The analysis is conducted with a system level simulation tool. This paper first indicates with single carrier simulations that, especially in small cells, terminals have spare power available for dual carrier operation. These observations are verified with dual carrier simulations by showing that the burst throughput can be practically doubled. In the…
Analysis of RRM limitations and restricted transmission periods for VoIP over HSDPA
2009
This paper studies how the performance of Voice over IP (VoIP) over High Speed Downlink Packet Access (HS-DPA) networks is affected if transmission to a User Equipment (UE) is stopped for specific amount of time during handover procedure. This paper also addresses the situation when it might be necessary to limit the number of UEs in a cell. The study showed that parameter settings for Radio Resource Management (RRM) algorithms can have an effect to the VoIP capacity: If handover lasts long enough for VoIP packets to be lost, or severe congestion occurs in a cell, VoIP capacity may be degraded.
Extended HSUPA coverage and enhanced battery saving opportunities with multiple TTI lengths
2010
3GPP has specified that terminals can be configured to use either 2 or 10 ms transmission time interval in high speed uplink packet access systems. The purpose of this paper is to evaluate the benefit of exploiting a mixture of both of the transmissions time intervals within a cell instead of only one. The study is quantified by means of studying the achievable coverage of voice over IP and possible battery saving benefits. The analysis is conducted with a system level simulator modeling network and terminal behavior in detail. The paper indicates that utilizing a mixture of both transmission time intervals can extend coverage whilst providing enhanced battery saving opportunities.
On Serving Cell Change Reliability in HSDPA Network
2009
In Wideband Code Division Multiple Access (WCDMA) networks the Signaling Radio Bearer (SRB) is transmitted downlink to inform the user i.a. when it needs to make a handover. When transmitting e.g. Voice over IP (VoIP) on High Speed Downlink Packet Access (HSDPA) SRB is mapped on HSDPA user data channel, High-Speed Downlink Shared Channel (HS-DSCH) in order to maximize voice capacity. The lack of support for soft handover (SHO) of HS-DSCH may compromise the reception of SRB and thus also a possible incoming serving HSDPA cell change command especially at the cell borders. This can lead to serious VoIP service degradation due to prolonged camping on a poor cell and in the worst case even to c…