Open Loop and Closed Loop Power Control Analysis on LTE

LTE downlink is using Orthogonal Frequency Division Multiple Access (OFDMA) multiple access system which have high invulnerability from multipath problem. One of the weakness of OFDM system is the high level from Peak to Average Power Ratio (PAPR) that requires higher level transmit power for maintaining the Bit Error Rate (BER) requirement. Using uplink scheme with Single Carrier FDMA (SC-FDMA) which is OFDMA modification, will be offered better level of PAPR than its conventional OFDM. The main problem of using OFDMA is the high level of PAPR, while using SC-FDMA the problem is intra-cell interference. Intra-cell or inter-cell interference is the common problem that can reduce the LTE performance. Minimizing received power for each users (UE) which is still at acceptable tolerance parameter, can be used for reducing the interference problem to another UE. Power control is the appropriate solution for minimizing the interference level. In this paper will be analyzed the power control using open loop and closed loop scheme at LTE network. The simulation result shows that without power control schemes, the transmit power of UE was 23 dBm. While, after applying power control scheme, the transmit power was 18.8 dBm at α=0.4 of open loop condition and 9.05 dBm at closed loop condition. Using this transmit power value as the UE power can improve the SINR performance. The SINR average value without power control scheme was only 20.38 dB which is lower than using open loop scheme was achieved 22.44 dB, and 24.02 dB at closed loop scheme.LTE downlink is using Orthogonal Frequency Division Multiple Access (OFDMA) multiple access system which have high invulnerability from multipath problem. One of the weakness of OFDM system is the high level from Peak to Average Power Ratio (PAPR) that requires higher level transmit power for maintaining the Bit Error Rate (BER) requirement. Using uplink scheme with Single Carrier FDMA (SC-FDMA) which is OFDMA modification, will be offered better level of PAPR than its conventional OFDM. The main problem of using OFDMA is the high level of PAPR, while using SC-FDMA the problem is intra-cell interference. Intra-cell or inter-cell interference is the common problem that can reduce the LTE performance. Minimizing received power for each users (UE) which is still at acceptable tolerance parameter, can be used for reducing the interference problem to another UE. Power control is the appropriate solution for minimizing the interference level. In this paper will be analyzed the power control using open loop and closed loop scheme at LTE network. The simulation result shows that without power control schemes, the transmit power of UE was 23 dBm. While, after applying power control scheme, the transmit power was 18.8 dBm at α=0.4 of open loop condition and 9.05 dBm at closed loop condition. Using this transmit power value as the UE power can improve the SINR performance. The SINR average value without power control scheme was only 20.38 dB which is lower than using open loop scheme was achieved 22.44 dB, and 24.02 dB at closed loop scheme

Studies on 6-sector-site deployment in downlink LTE

Mobile data traffic is expected to increase massively in the following years. Consequently, service operators are induced to increase the capacity of their networks continually to attract more subscribers and maximize their revenues. At the same time, they want to minimize operational costs and capital expenditures. Among the alternatives that aim to increase the network capacity, higher order sectorization, and in particular a six sectorized configuration, is nowadays attracting a lot of attention for LTE macro-cell deployments since a higher number of sectors per site results in improved site capacity and coverage. A six sectorized configuration is attractive for both roll-out phase and growth phase of the network. In the roll-out phase, the radio access network is planned with 6-sector sites instead of 3-sector sites with the advantage that less sites are needed for the same capacity and coverage requirements. In the growth phase, the six sectorized configuration can be used to upgrade existing 3-sector sites where the traffic grows beyond the current sites' capabilities. Therefore, no additional expensive and time consuming contracts need to be signed for the locations of the new sites, while the existing sites are used more efficiently. However, although potentially a 6-sector site can offer a double capacity than a 3-sector site, several factors prevent the capacity from growing proportionately to the number of sectors. Consequently, there is an uncertainty on whether the capacity gain is high enough to justify the extra costs of the additional equipment and, more specifically, whether the 6-sector-site deployment is more economically attractive than a 3-sector-site deployment. The aim of this report is to solve this uncertainty. First, we present the main factors that affect the capacity gain. Next, we quantify the impact of these factors on the capacity gain in downlink LTE with the use of a system level simulator. Finally, we use the results of the simulation study as inputs for an economic study to access the reasons for a possible deployment of 6-sector sites instead of 3-sector sites for LTE

Comparison of 3GPP LTE and 3GPP2 UMB

In the last years, technology evolution in mobile communications is mainly motivated by three relevant agents: (1) the market globalization and liberalization and the increasing competence among vendors and operators coming from this new framework, (2) the popularization of IEEE 802 wireless technologies within the mobile communications sector and, finally, (3) the exponential increase in the demand for advanced telecommunication services. Concerning the last item, the envisaged applications to be supported by current and future cellular systems include Voice over IP (VoIP), videoconference, push-to-talk over cellular (PoC), multimedia messaging, multiplayer games, audio and video streaming, content download of ring tones, video clips, Virtual Private Network (VPN) connections, web browsing, email access, File Transfer Protocol (FTP). Thus, the race towards IMT-Advanced was officially started in March 2008, when a Circular Letter was distributed asking for the submission of new technology proposals. Previous to this official call, the 3rd Partnership Project (3GPP) established the Long Term Evolution (LTE) and the 3rd Partnership Project 2 (3GPP2) established the Ultra Mobile Broadband. In this paper we have conducted a comparative study between UMB and 3GPP LTE by focusing on their first layers, i.e. Physical layer. The comparison specifically includes system architecture, radio aspects of the air interface such as radio access modes, multiple access technologies, multiple antenna technologies, modulation and mobility

Macro Diversity Combining Optimization in HSPA flat architecture

This thesis, Macro Diversity Combining Optimization in High Speed Packet Access (HSPA) flat architecture, concentrates on analyzing implementation alternatives of Marco Diversity Combining (MDC) in fiat architecture. When centralized elements, like Radio Network Controller (RNC), are removed from the architecture, centralized functionalities need to be implemented differently. One of the most important centralized functionality is Macro Diversity Combining which collects traffic from multiple base stations and improves radio performance like bit rate and coverage area. When this functionality is implemented inside base station traffic needs to be sent between base stations. Traffic between base stations creates new requirements for transport network and potentially also increases operator transport cost. In short, if MDC is fully implemented, traffic between base stations is maximized and opposite, if MDC is left out, radio performance is reduced. The thesis starts with the overview introduction of Universal Mobile Telecommunication System (UMTS) network. Here we discuss the architecture of the UMTS packets switched network, and the main functionalities of the Radio Resource Management (RRM): power control and handover control. A deeper look is taken into evolution of 3GPP packet access namely High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Data Access (HSUPA) plus the relevant HSDPA cell change and HSUPA handovers are covered. A short glance is also taken into the gains introduced by MDC. In this thesis four proposals presented in 3GPP to improve the MDC with regards to utilization of transport network, implementation complexity, radio performance, latency and amount of additions to existing 3GPP specifications are evaluated. Finally, an implementation alternative for MDC optimization in flat architecture is presented based on the proposals in 3GPP