Wideband TDD

Chitrapu, P.R.

doi:10.1002/0470861118

Cited by 10 publications

(4 citation statements)

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“…To analyze coexistence issues, this paper focuses on adjacent channel interference from an aggressor system (WiMax or TD-LTE) to a victim system (TD-LTE) in macrocellular scenarios. The adjacent channel interference (ACI) is the total interference from adjacent channels and mainly related to the amount of signal leakage from a transmitter, the amount of signal loss between two transceivers (i.e., coupling loss), and the ability of a receiver to suppress out of band interference [ 10 ]. The adjacent channel leakage is measured in terms of adjacent channel leakage ratio (ACLR), which is defined as the ratio of the desired signal power in its channel to the power measured in an adjacent channel.…”

Section: Uplink Scheduling and Adjacent-channel Coupling Loss Analmentioning

confidence: 99%

“…It is generally assumed that two TDD systems in adjacent bands are perfectly synchronized, but it is necessary to analyze the unsynchronized network for considering the worst-case scenarios. The interference between a BS and a UE operating in adjacent bands is not significant because the CL between the BS and the UE is high [ 10 ]. In the unsynchronized network, TDD can give rise to two more interference mechanisms, between two BSs (BS-to-BS) or two UEs (UE-to-UE).…”

Section: Uplink Scheduling and Adjacent-channel Coupling Loss Analmentioning

confidence: 99%

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Uplink Scheduling and Adjacent-Channel Coupling Loss Analysis for TD-LTE Deployment

Yeo

Moon²,

Kim

2014

The Scientific World Journal

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TD-LTE, one of the two duplexing modes in LTE, operates in unpaired spectrum and has the advantages of TDD-based technologies. It is expected that TD-LTE will be more rapidly deployed in near future and most of WiMax operators will upgrade their networks to TD-LTE gradually. Before completely upgrading to TD-LTE, WiMax may coexist with TD-LTE in an adjacent frequency band. In addition, multiple TD-LTE operators may deploy their networks in adjacent bands. When more than one TDD network operates in adjacent frequency bands, severe interference may happen due to adjacent channel interference (ACI) and unsynchronized operations. In this paper, coexistence issues between TD-LTE and other systems are analyzed and coexistence requirements are provided. This paper has three research objectives. First, frame synchronization between TD-LTE and WiMax is discussed by investigating possible combinations of TD-LTE and WiMax configurations. Second, an uplink scheduling algorithm is proposed to utilize a leakage pattern of ACI in synchronized operations. Third, minimum requirements for coexistence in unsynchronized operations are analyzed by introducing a concept of adjacent-channel coupling loss. From the analysis and simulation results, we can see that coexistence of TD-LTE with other TDD systems is feasible if the two networks are synchronized. For the unsynchronized case, some special cell-site engineering techniques may be required to reduce the ACI.

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Section: Uplink Scheduling and Adjacent-channel Coupling Loss Analmentioning

confidence: 99%

Section: Uplink Scheduling and Adjacent-channel Coupling Loss Analmentioning

confidence: 99%

Uplink Scheduling and Adjacent-Channel Coupling Loss Analysis for TD-LTE Deployment

Yeo

Moon²,

Kim

2014

The Scientific World Journal

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“…In general, the interference in CDMA systems is of the intra-cell and inter-cell type (Chitrapu, 2004). Due to the TDD nature of the air interface, interference is limited since fewer transmissions are simultaneously active on a time slot.…”

Section: Resource Allocation Constraintsmentioning

confidence: 99%

“…Referring to the strength-based power control, we consider that a given transmission power (depending on the traffic class) is employed for all the users scheduled on a slot, so that a minimum link budget is assured for the user among them at the greatest distance from the base station (such distance is lower than or equal to the cell radius, here denoted with R max ) (Chitrapu, 2004). For the sake of simplicity we assume that on each slot there is always at least one user at the maximum distance R max (conservative assumption).…”

Section: Resource Allocation Constraintsmentioning

confidence: 99%

Packet scheduling in third-generation mobile systems with UTRA-TDD air interface

et al. 2007

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UTRA-TDD is one of the adopted air interfaces for third-generation mobile communication systems (UMTS). In UTRA-TDD, information packets are transmitted organized into radio frames. A radio frame is divided into a fixed number of time slots and different packets can be sent on the same time slot by means of the Code Division Multiple Access technique. Packets belong to different traffic classes and have different formats and Quality of Service (QoS) requirements in terms of delay, transmission error probability and priority level. In this paper, we address the problem of scheduling packets for downlink transmissions in the time slots of a frame, in such a way that QoS requirements are fulfilled. In particular, exact pseudo-polynomial and heuristic scheduling algorithms are compared in terms of typical performance parameters. Computational results for three traffic classes show that the proposed algorithms are suitable for UTRA-TDD implementation, both for solution quality and computational time.

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Singular Value Decomposition Rank-Deficient-Based Estimators in TD-SCDMA Systems

Marzook

Ismail

Ali

et al. 2012

Circuits Syst Signal Process

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This paper presents a new joint channel estimation method for Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) systems based on a Singular Value Decomposition (SVD) reduced-rank technique. The system capacity is increased by increasing the highest number of users in one time slot. The additional channel estimation processing required for the increasing number of users is solved by adopting the reduced-rank technique, which estimates a limited number of parameters that are needed to describe the channel matrix and reduce the dimensionality of this matrix. Simulation results prove the validity of the proposed reduced-rank technique for channel estimation accuracy enhancing. Additionally, it is shown that the detectors based on the reduced-rank estimators outperform traditional channel estimators, contributing to 7.8 and 6.9 dB BER performance improvements for indoor and vehicular channels, respectively.

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Wideband TDD

Cited by 10 publications

References 0 publications

Uplink Scheduling and Adjacent-Channel Coupling Loss Analysis for TD-LTE Deployment

Uplink Scheduling and Adjacent-Channel Coupling Loss Analysis for TD-LTE Deployment

Packet scheduling in third-generation mobile systems with UTRA-TDD air interface

Singular Value Decomposition Rank-Deficient-Based Estimators in TD-SCDMA Systems

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