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Next-generation wireless networks such as LTE and WiMax can achieve throughputs of several Mbps with TCP. These higher throughputs, however, can easily be destroyed by frequent handoffs, which occur in urban environments due to shadowing. A primary reason for the throughput drop during handoffs is the out of order arrival of packets at the receiver. As a result, in this paper, we model the precise...
Near-live P2P video streaming is already popular among consumers, but typically this type of application is bound to fixed Internet access, as streaming requires a sustained bitrate over time and is less tolerant to environments with volatile throughput rates. For users moving at speeds larger than walking speed, P2P video streaming is hardly possible, as the achievable throughput for a single peer...
This paper presents a methodology for evaluating the quality of service (QoS) provided by a Universal Mobile Telecommunications System (UMTS) network for data services that use HTTP. Data collected from drive testing were used as the means to evaluate different drive routes of varying quality. The methodology presented in this paper can be easily modified to work with different networks.
In this paper, we present results from a study on the impact of antenna separation on LTE system performance. By means of system simulations we evaluate under which conditions a small or large antenna separation is preferable. We also provide empirical support to the simulation results by comparing with results from a measurement campaign.
This paper describes the implementation of a flexible Turbo and LDPC outer modem engine which is capable of supporting the WiFi(802.11n), WiMax(802.16e) and 3GPPLTE standard on the same hardware resources. The chip is implemented in a 65 nm CMOS technology and occupies 10.37 mm2. The decoder flexibility is offered by means of an application-specific instruction-set processor (ASIP), with full datapath...
This paper presents an efficient method for calculating the Precoding Matrix Indicator (PMI), Rank Indicator (RI) and Channel Quality Indicator (CQI) at a Long Term Evolution (LTE) User Equipment (UE). The indicators are required for spatial preprocessing and link adaption in the downlink of a 3GPP UMTS/LTE system. To reduce the computational burden for the UE, our method decomposes the problem into...
This paper presents a comparison between CDMA and SC-FDMA for reverse link (RL) cellular voice and data communications. The comparison is based on CDMA2000 1x (circuit-switched voice), CDMA2000 1xEV-DO (packet data) and 3GPP LTE Release 8 (SC-FDMA based packet voice and data). We illustrate various modes of LTE system operation and associated trade-offs. For the comparison of data communications we...
This paper evaluates the performance of highly loaded High Speed Uplink Packet Access (HSUPA) network with and without network wide static Interference Coordination (IC). IC alternates the priorities for user transmission periods throughout the network to achieve reduced interference levels and higher performance. A large variety of combinations including, e.g., different schedulers, cell center/edge...
In this paper, a novel interference coordination scheme based on Dynamic Resource Allocation (DRA) for mitigating inter-cell interference in Long Term Evolution (LTE) cellular systems is presented. In both OFDMA and SC-FDMA systems, inter-cell interference is the most important interference source. Inter-cell interference coordination is considered to improve coverage and increase date rate at cell...
The 3GPP LTE standard for mobile broadband includes multi-antenna transmission modes that improve performance, both in terms of coverage, spectral efficiency and peak throughput. The antenna system design, both at the eNB and at the UE is critical to a well performing system; it should be designed with the intended performance profile in mind. Field trials were performed in order to investigate the...
We consider the downlink of an Orthogonal Frequency Division Multiple Access (OFDMA) network. OFDMA transmission technology will be used in the next generation of wireless networks such as the LTE (Long Term Evolution) and WiMAX wireless standards. In such a channel, multiple User Equipments (UE) may each be allocated multiple Resource Blocks (RBs) in each frame. A RB is a collection of subcarriers...
The interference situation in the uplink of cellular networks, such as the 3GPP UTRAN Long Term Evolution (LTE), is usually highly volatile since from one transmission time interval to the other different users might be scheduled in nearby cells, thus often causing completely different levels of interference. This unstable behavior of the interference generally has a negative impact on the performance...
UMTS LTE system can support flexible bandwidth configuration up to 20 MHz. Currently, system enhancements are being considered to provide substantial improvements to LTE and allow it to meet or exceed IMT-Advanced requirements. One key enhancement feature is bandwidth extension via carrier aggregation to support deployment bandwidth up to 100 MHz. This will allow peak target data rates in excess of...
This paper studies the impact of HSPA equipments and devices evolution, from 3GPP R5 to R7 ones, on the capacity of a real macro-cell network. A simulation method has been developed. It combines drive test measurements, link-level simulations, and a statistical capacity model, which provides a reliable estimate of the network radio capacity. Different receiver schemes are simulated: linear receivers...
Higher Order Modulation (HOM, 64-QAM) and Multiple Input Multiple Output (MIMO) transmissions are two key features introduced in the Release 7 (HSPA+) WCDMA systems to improve downlink performance. This paper focuses on the performance analysis of 64-QAM and MIMO in the WCDMA system. We describe the equalizer design for supporting these features as well as the simulation results demonstrating the...
We evaluate the performance of the uplink of a 3GPP UTRAN Long Term Evolution (LTE) system with intra-site cooperation, where different sectors belonging to the same site may cooperate with each other in order to improve the system performance. This represents an intermediate step towards general coordinated multipoint (CoMP) systems as currently under discussion for LTE-Advanced, where a cooperation...
Coordinated Multi-Point transmission and reception (CoMP) technique has been adopted in LTE-Advanced as one of the promising techniques because it can significantly increase the throughput of the cell edge user and the total sector throughput for both downlink and uplink transmission. Compared with conventional cellular system, CoMP can reduce inter-cell interference (ICI) significantly. On the other...
The newly standardized Dual-Carrier HSDPA offers two-carrier aggregation on the downlink. In this paper, we investigate the performance gains from the dual-carrier operations with both full buffer and bursty traffic models. With full buffer traffic, dual-carrier offers dynamic load balancing and increase in user data rate, system capacity and spectral efficiency. All the users throughout the system...
This paper studies the different ways of extending wireless coverage for high data rates and improving the data capacity in a building. The solutions considered include deployments of single or multiple small base stations, i.e. Picocell or Femtocell, and distributed antenna system, operated on the same frequency as the macro cellular network. We look at the radio performance of each solution in a...
3rd Generation Partnership Project (3GPP) responsible of the standardization of 3G systems selected dual stream Transmit Antenna Array (D-TxAA) as the Multiple Input - Multiple Output (MIMO) scheme for High Speed Downlink Packet Access (HSDPA) in 3GPP specification Release 7. MIMO doubles the theoretical peak data rate of HSDPA from 14.4 Mbps to 28.8 Mbps. However, successful reception of dual stream...
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