Systems and methodologies are described that facilitate cycling across antennas for channel quality information (CQI) computation and data transmission in a multiple-input multiple-output (MIMO) wireless communication environment. Pilots can be obtained by a wireless terminal. Further, virtual antennas that can be supported by a channel can be identified based upon an analysis of the pilots. Moreover, CQI computations can be effectuated for each of the supported virtual antennas; thereafter, the CQI data can be sent to a base station for data transmission scheduling. Additionally, the base station can schedule transmission based upon the CQI data and/or fairness considerations. When scheduled, data transmission can occur by cycling across the supported virtual antennas.

Providing antenna diversity in a wireless communication system

This paper studies downlink resource reuse schemes for cellular networks with coexisting femtocells and macrocells We examine two reuse schemes, termed split reuse and shared reuse In this paper, we develop an analytical model of resource allocation based on random graphs In our model, arbitrarily chosen communication links interfere with each other with a certain probability, which depends upon whether the links belong to femtocell or macrocell users Using this model, we establish asymptotic bounds on the minimum number of resource blocks required to make an interference-free resource assignment for all the users in the network for large numbers of users We assess these bounds using a simple greedy resource allocation algorithm to demonstrate that the bounds are reasonable in finite networks of plausible size By applying the bounds, we establish the expected impact of femtocell networks on macrocell resource allocation under a wide variety of interference scenarios Further, we assess the efficiency loss associated with split reuse, as an aid to determining whether resource allocators should use the simpler split reuse scheme or attempt to tackle the complexity and overhead associated with shared reuse

/pdf/on-resource-reuse-for-cellular-networks-with-femto-and-7wpvv07qma.pdf

On Resource Reuse for Cellular Networks with Femto- and Macrocell Coexistence

Disclosed is a method for a femtocell to reduce interference with an overlapping macrocell. The femtocell determines soft-frequency-reuse (“SFR”) information of the macrocell. From that information, the femtocell determines which frequency sub-channels are assigned by the macrocell for its cell-center users and which frequency sub-channels are assigned for cell-edge users. (Cell-edge users are given a higher transmission power profile in order to overcome potential interference with neighboring macrocells.) Then, the femtocell selects from the cell-center user frequency sub-channels for transmission to the femtocell's users. By transmitting on the cell-center user frequency sub-channels, the femtocell reduces interference with the overlapping macrocell. The femtocell continues to update its knowledge of the macrocell's SFR information and re-assigns frequency sub-channels as the SFR changes. If the macrocell detects that one of its cell-center users is “close enough” to the femtocell, then the macrocell re-assigns the cell-center user as a cell-edge user to overcome interference.

In a radio network environment, reducing interference among overlapping cells

Intercell interference is the main issue limiting the capacity of modern orthogonal frequency-division multiple access based cellular networks. Recently, extensive research work has been carried out in this field, and intercell interference coordination techniques have been recognized as key enablers of current and future cellular technologies. In this article, i a comprehensive survey of the most representative contributions is provided together with ii a generic methodology to measure their actual merit. The performance of several interference avoidance strategies has been evaluated both from system and user point of view in the context of a Long Term Evolution LTE-based network considering not only synthetic cellular scenarios but also realistic deployments. Our literature review indicates that there is a need for adaptive/operator-customizable low-complex intercell interference coordination ICIC schemes suitable for realistic LTE deployments. Results obtained by means of a comprehensive set of simulations corroborate and support this premise. In this article, it is shown that simultaneous gains in terms of spectral/energy efficiency and fairness can be achieved through dynamic mechanisms with respect to both classic hard reuse schemes and static ICIC techniques. Besides numerical results, a novel merit assessment methodology based on several weighted performance metrics is proposed. Our findings show that dynamic schemes outperform static techniques by around 20-35% in realistic deployments. Copyright © 2012 John Wiley & Sons, Ltd.

On the need for dynamic downlink intercell interference coordination for realistic Long Term Evolution deployments

The method is a method of setting radio resources which a pico base station ( 100 ) and a macro base station ( 200 ) can use for wireless communication with a terminal, and includes obtaining loads the pico base station ( 100 ) and the macro base station ( 200 ), calculating a first delay index of the pico base station using the load of the pico base station ( 100 ), calculating using the load of the macro base station ( 200 ) a second delay index of the macro base station ( 200 ) in case where the macro base station ( 200 ) has set radio resources whose use is limited, and calculating a ratio of the radio resources whose use is limited by the macro base station ( 200 ) based on the first and second delay indices, and setting the radio resources whose use is limited in the second communication area using the ratio of the radio resources whose use is limited.

Radio resource setting method, base station, radio resource setting system, and non-transitory computer readable medium

In this paper, we present a dynamic resource allocation algorithm, termed Dynamic Major group Allocation (DMA), based on Soft Frequency Reuse (SFR) which is an efficient method to mitigate inter-cell interference (ICI) in Orthogonal Frequency Division Multiple Access (OFDMA) systems. DMA defines the method that Radio Network Controller (RNC) orthogonally assigns resource to Cell Edge Users (CEU) in neighboring cells (or sectors) firstly, and then each cell allocal.es its residual resource to Cell Center Users (CCU) according to PF scheduling. Simulation results demonstrate that the proposed DMA algorithm carries superior throughput performance of CEU over the traditional two-level resource allocation scheme (TLA) which simply combines SFR with PF.

A Dynamic Resource Allocation Scheme Based on Soft Frequency Reuse for OFDMA Systems

Group-based User Pairing for Virtual MIMO in LTE

In this paper, a downlink RRM (radio resource management) scheme is proposed for packet transmission in MIMO-OFDM (Multiple Input Multiple Output-Orthogonal Frequency-Division Multiplexing) wireless communication systems. Within this scheme, the useful OFDM subcarriers in each TTI (Transmission Time Interval) are divided into two groups: LRG (localized resource group) and DRG (distributed resource group). LRG is TF (time-frequency) continuous, and it is scheduled to low-speed users based on the slowly varying channel states to obtain better multi-user diversity. While DRG is composed of discrete TF hopping patterns, and it is allocated to high-speed users, in order to fully utilize time-frequency diversity against the rapid varying channels. Multi-antennas are adopted in spatial multiplexing mode. A two-step proportional fair scheduling is also proposed to work with the scheme. Simulation results show that the proposed scheme can achieve a higher system throughput than the scheme adopting chunk based scheduling only, and it can also guarantee fairness among users.

Downlink Resource Management for Packet Transmission in MIMO-OFDM Wireless Communication Systems

In this paper, an analysis framework to be used for WCDMA (Wideband Code Division Multiple Access) networks dimensioning is proposed. The work attempts to combine interference limitation with hardware limitation, also considering the multi-service dimension of a WCDMA cellular system. The effect of these two factors towards access capacities of mixed service is analyzed, and with the method provided in this paper, the number of channel cards needed for a certain distribution of traffic in a cell can be calculated, which is meaningful for dimensioning and building WCDMA networks to save the radio network capital expenditures efficiently while providing enough quality.

Analysis of Access Capacities for Mixed Services in WCDMA Networks

This paper represents a method based on generalizing Delbrouck's algorithm for calculating the access capacities of multi-service time division duplex-code division multiple access (TDD-CDMA) networks. The method models the system as a multi-service model with state dependent soft blocking probabilities, and it uses the soft capacity limit caused by TDD-CDMA system in calculating the call blocking rate of multi-services. The traffic models used in this method are insensitive to the service time distribution and thus the method is very robust for applications. So it is more accurate than multi-dimensional Erlang-B formula, which does not consider the soft capacity, and it is also simpler than resolving the complex linear system equations with soft capacity. The paper provides both analytical results and simulation results to support the method, and these results match. Thus the proposed method can be used in TDD-CDMA network dimensioning and optimizing.

Multi-Service Access Capacities Analysis of TDDCDMA System with Soft Blocking

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