Showing papers by "NTT DoCoMo published in 2014"

User terminal, radio base station and radio communication method

Abstract: The present invention is designed to provide a user terminal, a radio base station and a radio communication method of novel structures that can achieve a good communication environment. A radio base station non-orthogonal-multiplexes downlink signals for a plurality of user terminals over a given radio resource, a user terminal having received the downlink signals for the plurality of user terminals decodes downlink signal for another user terminal, judges whether or not the downlink signal for the other user terminal has been successfully received, based on the decoding result of the downlink signal, reports a judgement result as to whether or not the downlink signal for the other user terminal has been successfully received and a judgement result as to whether or not a downlink signal for the user terminal has been successfully received, to the radio base station, and then the radio base station executes retransmission control of downlink signals based on reports from the user terminal.

Design considerations for a 5G network architecture

Abstract: This article presents an architecture vision to address the challenges placed on 5G mobile networks. A two-layer architecture is proposed, consisting of a radio network and a network cloud, integrating various enablers such as small cells, massive MIMO, control/user plane split, NFV, and SDN. Three main concepts are integrated: ultra-dense small cell deployments on licensed and unlicensed spectrum, under control/user plane split architecture, to address capacity and data rate challenges; NFV and SDN to provide flexible network deployment and operation; and intelligent use of network data to facilitate optimal use of network resources for QoE provisioning and planning. An initial proof of concept evaluation is presented to demonstrate the potential of the proposal. Finally, other issues that must be addressed to realize a complete 5G architecture vision are discussed.

Radio base station, user terminal, and radio communication method

Abstract: The present invention is designed to improve spectral efficiency in a radio communication system which can use non-orthogonal multiple access (NOMA). Steps are provided in which a radio base station configures one of a plurality of transmission mode including a first transmission mode, which groups a plurality of transmission methods including a transmission method to employ non-orthogonal multiple access (NOMA) and multiple-user multiple-input and multiple-output (MU-MIMO), and a second transmission mode, which groups a plurality of transmission methods including a transmission method to employ this NOMA and open-loop transmit diversity, and transmits a downlink signal for this user terminal based on the configured transmission mode.

User terminal and radio communication method

Abstract: The present invention is designed to enable adequate transmission power control when inter-base station CA is employed. When inter-base station CA is employed, radio base stations detect when a user terminal's transmission power reaches the maximum transmission power, and execute control to cancel this. For example, a user terminal has a transmission section that transmits an uplink physical channel to each component carrier, a power headroom generating section that generates power headroom, which is extra transmission power of the subject terminal, and a control section that, when the value of the power headroom becomes 0 or less, executes control so that the power headroom is triggered and reported to the radio base stations.

Scalable Synchronization and Reciprocity Calibration for Distributed Multiuser MIMO

Abstract: Large-scale distributed Multiuser MIMO (MU-MIMO) is a promising wireless network architecture that combines the advantages of "massive MIMO" and "small cells." It consists of several Access Points (APs) connected to a central server via a wired backhaul network and acting as a large distributed antenna system. We focus on the downlink, which is both more demanding in terms of traffic and more challenging in terms of implementation than the uplink. In order to enable multiuser joint precoding of the downlink signals, channel state information at the transmitter side is required. We consider Time Division Duplex (TDD), where the downlink channels can be learned from the user uplink pilot signals, thanks to channel reciprocity. Furthermore, coherent multiuser joint precoding is possible only if the APs maintain a sufficiently accurate relative timing and phase synchronization. AP synchronization and TDD reciprocity calibration are two key problems to be solved in order to enable distributed MU-MIMO downlink. In this paper, we propose novel over-the-air synchronization and calibration protocols that scale well with the network size. The proposed schemes can be applied to networks formed by a large number of APs, each of which is driven by an inexpensive 802.11-grade clock and has a standard RF front-end, not explicitly designed to be reciprocal. Our protocols can incorporate, as a building block, any suitable timing and frequency estimator. Here we revisit the problem of joint ML timing and frequency estimation and use the corresponding Cramer-Rao bound to evaluate the performance of the synchronization protocol. Overall, the proposed synchronization and calibration schemes are shown to achieve sufficient accuracy for satisfactory distributed MU-MIMO performance.

DialBetics: A Novel Smartphone-based Self-management Support System for Type 2 Diabetes Patients

Abstract: Numerous diabetes-management systems and programs for improving glycemic control to meet guideline targets have been proposed, using IT technology. But all of them allow only limited—or no—real-time interaction between patients and the system in terms of system response to patient input; few studies have effectively assessed the systems’ usability and feasibility to determine how well patients understand and can adopt the technology involved. DialBetics is composed of 4 modules: (1) data transmission module, (2) evaluation module, (3) communication module, and (4) dietary evaluation module. A 3-month randomized study was designed to assess the safety and usability of a remote health-data monitoring system, and especially its impact on modifying patient lifestyles to improve diabetes self-management and, thus, clinical outcomes. Fifty-four type 2 diabetes patients were randomly divided into 2 groups, 27 in the DialBetics group and 27 in the non-DialBetics control group. HbA1c and fasting blood sugar (FBS) values declined significantly in the DialBetics group: HbA1c decreased an average of 0.4% (from 7.1 ± 1.0% to 6.7 ± 0.7%) compared with an average increase of 0.1% in the non-DialBetics group (from 7.0 ± 0.9% to 7.1 ± 1.1%) (P = .015); The DialBetics group FBS decreased an average of 5.5 mg/dl compared with a non-DialBetics group average increase of 16.9 mg/dl (P = .019). BMI improvement—although not statistically significant because of the small sample size—was greater in the DialBetics group. DialBetics was shown to be a feasible and an effective tool for improving HbA1c by providing patients with real-time support based on their measurements and inputs.

A new control plane for 5G network architecture with a case study on unified handoff, mobility, and routing management

Abstract: The tremendous growth in wireless Internet use is showing no signs of slowing down. Existing cellular networks are starting to be insufficient in meeting this demand, in part due to their inflexible and expensive equipment as well as complex and non-agile control plane. Software-defined networking is emerging as a natural solution for next generation cellular networks as it enables further network function virtualization opportunities and network programmability. In this article, we advocate an all-SDN network architecture with hierarchical network control capabilities to allow for different grades of performance and complexity in offering core network services and provide service differentiation for 5G systems. As a showcase of this architecture, we introduce a unified approach to mobility, handoff, and routing management and offer connectivity management as a service (CMaaS). CMaaS is offered to application developers and over-the-top service providers to provide a range of options in protecting their flows against subscriber mobility at different price levels.

Minimizing Base Station Power Consumption

Abstract: We propose a new radio resource management algorithm which aims at minimizing the base station supply power consumption for multi-user MIMO-OFDM. Given a base station power model that establishes a relation between the RF transmit power and the supply power consumption, the algorithm optimizes the trade-off between three basic power-saving mechanisms: antenna adaptation, power control and discontinuous transmission. The algorithm comprises two steps: a) the first step estimates sleep mode duration, resource shares and antenna configuration based on average channel conditions and b) the second step exploits instantaneous channel knowledge at the transmitter for frequency selective time-variant channels. The proposed algorithm finds the number of transmit antennas, the RF transmission power per resource unit and spatial channel, the number of discontinuous transmission time slots, and the multi-user resource allocation, such that supply power consumption is minimized. Simulation results indicate that the proposed algorithm is capable of reducing the supply power consumption by between 25% and 40%, dependend on the system load.

Channel modelling for the fifth generation mobile communications

Abstract: The main objective of this paper is to present major challenges regarding the fifth generation (5G) mobile communications propagation modelling work in the European 7 th framework project METIS (Mobile and wireless communications Enablers for the Twenty-twenty Information Society). The goal of the propagation work in METIS is to provide adequate propagation models for 5G. For this purpose corresponding deficiencies of present commonly used models are identified. Further, the lack of available channel models for several propagation scenarios has been assessed. Based on this assessment the framework of 5G channel modelling is sketched. As propagation measurement campaigns are a crucial part of this work they are illustrated with a few examples.

Multi-User Proportional Fair Scheduling for Uplink Non-Orthogonal Multiple Access (NOMA)

Abstract: Non-orthogonal multiple access (NOMA) is a promising radio access technique for LTE release 13 and beyond. In this paper, we focus on the investigation of the system performance for uplink NOMA with an advanced successive interference cancellation (SIC) receiver applied in the base station side. In NOMA, more than one user can be multiplexed simultaneously in the same frequency bandwidth, which demands multi-user scheduling. In our study, we propose an enhanced proportional fair (PF) based scheduling scheme for non-orthogonal multiplexed users with contiguous resource allocation to retain the SC-FDM property. In order to reduce the scheduling complexity for non-orthogonal multiple access, a greedy consecutive resource allocation method is adopted. Moreover, since the interference condition becomes more complicated in NOMA, we consider the application of fractional frequency reuse (FFR) to NOMA to further enhance the performance of cell-edge users. In simulation results, the system performance of NOMA by using the proposed PF-based scheduling algorithm is evaluated. The results show that NOMA significantly enhances the uplink system performance compared to the conventional orthogonal multiple access.

When Queueing Meets Coding: Optimal-Latency Data Retrieving Scheme in Storage Clouds

Abstract: In this paper, we study the problem of reducing the delay of downloading data from cloud storage systems by leveraging multiple parallel threads, assuming that the data has been encoded and stored in the clouds using fixed rate forward error correction (FEC) codes with parameters (n, k). That is, each file is divided into k equal-sized chunks, which are then expanded into n chunks such that any k chunks out of the n are sufficient to successfully restore the original file. The model can be depicted as a multiple-server queue with arrivals of data retrieving requests and a server corresponding to a thread. However, this is not a typical queueing model because a server can terminate its operation, depending on when other servers complete their service (due to the redundancy that is spread across the threads). Hence, to the best of our knowledge, the analysis of this queueing model remains quite uncharted. Recent traces from Amazon S3 show that the time to retrieve a fixed size chunk is random and can be approximated as a constant delay plus an i.i.d. exponentially distributed random variable. For the tractability of the theoretical analysis, we assume that the chunk downloading time is i.i.d. exponentially distributed. Under this assumption, we show that any work-conserving scheme is delay-optimal among all on-line scheduling schemes when k = 1. When k > 1, we find that a simple greedy scheme, which allocates all available threads to the head of line request, is delay optimal among all on-line scheduling schemes. We also provide some numerical results that point to the limitations of the exponential assumption, and suggest further research directions.

Wireless base station, user terminal, and wireless communication method

Abstract: The purpose of the present invention is to effectively utilize frequency resources, even in cases when a mixture of a plurality of user terminals having different capabilities is present. A wireless base station which uses a plurality of component carriers to communicate with user terminals is provided with: a setting unit which sets, in the component carriers, first carrier-type subframes capable of being received respectively by a plurality of user terminals having different capabilities, and second carrier-type subframes capable of being received by a portion of the plurality of user terminals; and a transmitting unit which uses the first carrier type and the second carrier type to transmit downlink signals to the user terminals. The setting unit sets at least one of the plurality of component carriers so as to cause the first carrier-type subframes and the second carrier-type subframes therein to dynamically change.

User association and load balancing for cellular massive MIMO

Abstract: Massive MIMO is expected to play a key role in coping with the predicted mobile-data traffic explosion. Indeed, in combination with small cells and TDD operation, it promises large throughputs per unit area with low latency. In this paper we focus on the problem of balancing the load across networks with massive MIMO base-stations (BSs). The need for load balancing arises from variations in the user population density and is more pronounced in small cells due to the large variability in coverage area. We consider methods for load balancing over networks with small and large massive MIMO BSs. As we show, the distinct operation and properties of massive MIMO enable practical resource-efficient load-balancing methods with near-optimal performance.

TOFEC: Achieving Optimal Throughput-Delay Trade-off of Cloud Storage Using Erasure Codes

Abstract: Our paper presents solutions using erasure coding, parallel connections to storage cloud and limited chunking (i.e., dividing the object into a few smaller segments) together to significantly improve the delay performance of uploading and downloading data in and out of cloud storage. TOFEC is a strategy that helps front-end proxy adapt to level of workload by treating scalable cloud storage (e.g. Amazon S3) as a shared resource requiring admission control. Under light workloads, TOFEC creates more smaller chunks and uses more parallel connections per file, minimizing service delay. Under heavy workloads, TOFEC automatically reduces the level of chunking (fewer chunks with increased size) and uses fewer parallel connections to reduce overhead, resulting in higher throughput and preventing queueing delay. Our trace-driven simulation results show that TOFEC's adaptation mechanism converges to an appropriate code that provides the optimal delay-throughput trade-off without reducing system capacity. Compared to a non-adaptive strategy optimized for throughput, TOFEC delivers 2.5× lower latency under light workloads; compared to a non-adaptive strategy optimized for latency, TOFEC can scale to support over 3× as many requests. Index Terms—FEC, Cloud storage, Queueing, Delay

Fast cloud: pushing the envelope on delay performance of cloud storage with coding

Abstract: Our paper presents solutions that can significantly improve the delay performance of putting and retrieving data in and out of cloud storage. We first focus on measuring the delay performance of a very popular cloud storage service Amazon S3. We establish that there is significant randomness in service times for reading and writing small and medium size objects when assigned distinct keys. We further demonstrate that using erasure coding, parallel connections to storage cloud and limited chunking (i.e., dividing the object into a few smaller objects) together pushes the envelope on service time distributions significantly (e.g., 76%, 80%, and 85% reductions in mean, 90th, and 99th percentiles for 2-MB files) at the expense of additional storage (e.g., 1.75x). However, chunking and erasure coding increase the load and hence the queuing delays while reducing the supportable rate region in number of requests per second per node. Thus, in the second part of our paper, we focus on analyzing the delay performance when chunking, forward error correction (FEC), and parallel connections are used together. Based on this analysis, we develop load-adaptive algorithms that can pick the best code rate on a per-request basis by using offline computed queue backlog thresholds. The solutions work with homogeneous services with fixed object sizes, chunk sizes, operation type (e.g., read or write) as well as heterogeneous services with mixture of object sizes, chunk sizes, and operation types. We also present a simple greedy solution that opportunistically uses idle connections and picks the erasure coding rate accordingly on the fly. Both backlog-based and greedy solutions support the full rate region and provide best mean delay performance when compared to the best fixed coding rate policy. Our evaluations show that backlog-based solutions achieve better delay performance at higher percentile values than the greedy solution.

Subspace Alignment Chains and the Degrees of Freedom of the Three-User MIMO Interference Channel

Abstract: We show that the three-user MT × MR Multiple-Input Multiple-Output (MIMO) interference channel where each transmitter is equipped with MT antennas and each receiver is equipped with MR antennas has (M) d(M, N) =Δ min (M/2-1/κ, N/2+1/κ) degrees of freedom (DoF) normalized by time, frequency, and space dimensions, where =Δ min(MT, MR), N =Δ max(MT, MR), κ =Δ ⌈M/N-M⌉. While the DoF outer bound of d(M, N) is established for every MT, MR value, the achievability of d(M, N) DoF is established in general subject to a normalization with respect to spatial extensions, i.e., the scaling of the number of antennas at all nodes. In particular, we show that qd(M, N) DoF are achievable for the three-user qMT × qMR MIMO interference channel, for some positive integer q, which may be seen as a spatial extension factor. q is the scaling factor needed to make the value qd(M, N) an integer. Given spatial extensions, the achievability relies only on linear beamforming based interference alignment schemes and requires neither channel extensions nor channel variations in time or frequency. In the absence of spatial extensions, it is shown through examples how essentially the same interference alignment scheme may be applied over time-extensions over either constant or time-varying channels. The central new insight to emerge from this paper is the notion of subspace alignment chains as the DoF bottlenecks. The subspace alignment chains are instrumental both in identifying the extra dimensions to be provided by a genie to a receiver for the DoF outer bound, as well as in the construction of the optimal interference alignment schemes. The DoF value d(M, N) is a piecewise linear function of M, N, with either M or N being the bottleneck within each linear segment, whereas the other value contains some redundancy, i.e., it can be reduced without reducing the DoF. The corner points of these piecewise linear segments correspond to two sets, A={1/2, 2/3, 3/4, ...}and B={1/3, 3/5, 5/7, ...}. The set A contains all those values of M/N and only those values of M/N for which there is redundancy in both M and N, i.e., either can be reduced without reducing the DoF. The set B contains all those values of M/N and only those values of M/N for which there is no redundancy in either M or N, i.e., neither can be reduced without reducing the DoF. Because A and B represent settings with maximum and minimum redundancy, essentially they are the basis for the DoF outer bounds and inner bounds, respectively. Our results settle the question of feasibility of linear interference alignment, introduced previously by Cenk et al., for the three-user MT × MR MIMO interference channel, completely for all values of MT, MR. In particular, we show that the linear interference alignment problem (MT × MR, d)3 (as defined in previous paper by Cenk et al.) is feasible if and only if d ≤ d(M, N). With the exception of the values M/N ∈ B, and only with that exception, we show that for every M/N value there are proper systems (as defined by Cenk et al.) that are not feasible. Evidently the redundancy contained in all other values of M/N manifests itself as superfluous variables that are not discounted in the definition of proper systems, thus creating a discrepancy between proper and feasible systems. Our results show that M/N ∈ A are the only values for which there is no DoF benefit of joint processing among co-located antennas at the transmitters or receivers. This may also be seen as a consequence of the maximum redundancy in the M/N ∈ A settings.

Experimental mm wave 5G cellular system

Abstract: Bolstered by the ever increasing processing power of smart devices and combined with the new innovative applications, cellular data traffic demand is expected to increase a 10000x by 2025. Simultaneously, the telecommunication industry is converging on a common set of 5G requirements specifying 10x peak rates, 10x reductions in latency and 100x increases in cell edge rates over 4G cellular. Researchers are now looking to higher frequencies to meet demand and achieve the new requirements. This paper describes an experimental 5G system designed to operate at 73.5 GHz with a 1 GHz BW. The system communicates using a 28 dB gain antenna having a narrow 3 degree half-power beamwidth serving fully mobile user devices moving at pedestrian speeds. This experimental system is implemented in collaboration with Nokia and NTT DOCOMO [1][2].

System-level performance of downlink NOMA combined with SU-MIMO for future LTE enhancements

Abstract: This paper investigates the system-level performance of downlink non-orthogonal multiple access (NOMA) combined with single user MIMO (SU-MIMO) for future LTE (Long-Term Evolution) enhancements. The goal is to clarify the performance gains of NOMA combined with SU-MIMO transmission, taking into account the LTE radio interface such as frequency-domain scheduling, adaptive modulation and coding (AMC), and NOMA specific functionalities such as multi-user pairing/ordering and transmit power allocation. In particular, we propose practical schemes to efficiently combine NOMA with open-loop SU-MIMO (Transmission Mode 3: TM3) and closed-loop SU-MIMO (Transmission Mode 4: TM4) specified in LTE. Based on computer simulations, we compare NOMA performance gains for different granularities of scheduling and MCS (modulation and coding scheme) selection, for both genie-aided channel quality information (CQI) estimation and approximated CQI estimation, and using different number of power sets. Evaluation results show that NOMA can still provide a hefty portion of its expected gains even with approximated CQI estimation and limited number of power sets, and also when LTE compliant subband scheduling and wideband MCS are applied.

User device and base station

Abstract: This disclosure pertains to a technology for reducing the flashlight effect in 3D MIMO. One mode of this invention pertains to a user device that has the following: a transmission/reception unit that receives an interfering-beam-candidate list containing directional beams transmitted by a serving base station and interfering-beam candidates transmitted by a neighboring base station; a measurement unit that measures the received quality levels of reference signals transmitted via the respective directional beams in the received interfering-beam-candidate list; and an interference-information generation unit that generates interference information on the basis of the measured received quality levels. The transmission/reception unit sends the generated interference information to the serving base station or the neighboring base station.

Considerations on downlink non-orthogonal multiple access (NOMA) combined with closed-loop SU-MIMO

Abstract: As a promising downlink multiple access scheme for further cellular enhancements toward 5G, non-orthogonal multiple access (NOMA) improves both cell average and cell-edge user throughput compared to orthogonal multiple access (OMA) in the cellular downlink. When NOMA is combined with multi-antenna technology in practice, some aspects are of great interest, such as error propagation (EP) of successive interference cancellation (SIC) receiver and user velocity. This paper investigates the system-level throughput of NOMA with closed-loop single-user multiple-input multiple-output (SU-MIMO) in the cellular downlink and clarifies the potential gains over OMA with SU-MIMO taking into account these practical aspects. Two EP models are presented into the NOMA with closed-loop (CL) SU-MIMO. Their impacts on performance of NOMA with CL SU-MIMO are investigated by system-level simulations with practical assumptions. Furthermore, impact of user velocity on performance gain of NOMA with CL SU-MIMO is also evaluated. Simulation results show that even with the worst case EP model, NOMA with CL SU-MIMO can still provide large performance gains for both low and high mobility scenarios.

Analytical Modeling of Heterogeneous Cellular Networks: Geometry, Coverage, and Capacity

Abstract: This self-contained introduction shows how stochastic geometry techniques can be used for studying the behaviour of heterogeneous cellular networks (HCNs). The unified treatment of analytic results and approaches, collected for the first time in a single volume, includes the mathematical tools and techniques used to derive them. A single canonical problem formulation encompassing the analytic derivation of Signal to Interference plus Noise Ratio (SINR) distribution in the most widely-used deployment scenarios is presented, together with applications to systems based on the 3GPP-LTE standard, and with implications of these analyses on the design of HCNs. An outline of the different releases of the LTE standard and the features relevant to HCNs is also provided. A valuable reference for industry practitioners looking to improve the speed and efficiency of their network design and optimization workflow, and for graduate students and researchers seeking tractable analytical results for performance metrics in wireless HCNs.

User terminal, base station and radio communication method

Abstract: The present invention is designed to carry out uplink transmission adequately even when CA is executed by applying different duplex modes between multiple cells. A user terminal communicates with an FDD cell and a TDD cell that employ carrier aggregation, and has a receiving section that receives DL signals transmitted from each cell, and a feedback control section that allocates and feeds back delivery acknowledgement signals in response to the DL signals in a predetermined UL subframe, and, regardless of which cell is configured as a primary cell, the feedback control section, when transmitting only a delivery acknowledgement signal in response to the DL signal of one cell, transmits the delivery acknowledgement signal from the one cell by using a PUCCH resource that is determined from a downlink control channel resource of the DL signal, and, when transmitting delivery acknowledgement signals in response to the DL signals of both cells, transmits the delivery acknowledgement signals by using a PUCCH resource of one or both of the cells.

Base station and user equipment

Abstract: The present disclosure relates to techniques for implementing efficient beam forming in 3D MIMO. One aspect of the present invention relates to abase station, comprising: a beam forming unit configured to form multiple directional beams in accordance with a predetermined beam arrangement; a transmission and reception unit configured to transmit reference signals in the formed multiple directional beams; and a feedback information acquisition unit configured to acquire feedback information from user equipment receiving the reference signals.

Capacity analysis of LTE-Advanced HetNets with reduced power subframes and range expansion

Abstract: The use of reduced power subframes in LTE Rel. 11 can improve the capacity of heterogeneous networks (HetNets) while also providing interference coordination to the picocell-edge users. However, in order to obtain maximum benefits from the reduced power subframes, setting the key system parameters, such as the amount of power reduction, carries critical importance. Using stochastic geometry, this paper lays down a theoretical foundation for the performance evaluation of HetNets with reduced power subframes and range expansion bias. The analytic expressions for average capacity and 5th percentile throughput are derived as a function of transmit powers, node densities, and interference coordination parameters in a two-tier HetNet scenario and are validated through Monte Carlo simulations. Joint optimization of range expansion bias, power reduction factor, scheduling thresholds, and duty cycle of reduced power subframes is performed to study the trade-offs between aggregate capacity of a cell and fairness among the users. To validate our analysis, we also compare the stochastic geometry-based theoretical results with the real macro base station (MBS) deployment (in the city of London) and the hexagonal grid model. Our analysis shows that with optimum parameter settings, the LTE Rel. 11 with reduced power subframes can provide substantially better performance than the LTE Rel. 10 with almost blank subframes, in terms of both aggregate capacity and fairness.

User terminal, radio base station, radio communication method and radio communication system

Abstract: A user terminal that can communicate with a radio base station by using a licensed band and an unlicensed band is disclosed. The user terminal includes a receiving section that receives downlink signals transmitted in the licensed band and the unlicensed band, a measurement section that measures a downlink signal transmitted in the unlicensed band, and a control section that controls feedback of a measurement result. The receiving section receives information related to a command for the measurement in the unlicensed band and/or a command for the feedback of the measurement result by using the licensed band.

Map information display device, map information display method, and map information display program

Abstract: A map information display device (1) comprises: a touch panel (11) for displaying map information while accepting a touch operation from a user; a touch position detector (12) for detecting a touch position on a touch panel (11); a building determination unit (16) for determining whether or not a building with displayable internal information exists in the map information displayed on the touch panel (11); and a floor-selection menu display processing unit (18) for displaying a floor selection menu having selection items corresponding to displayable floors near the touch position on the touch panel (11) when the building determination unit (16) determines that a building with displayable internal information exists.

Beam selecting method, base station, and user equipment

Abstract: A beam selection method in a mobile communication system including a base station with multiple antennas and user equipment conducting radio communication with the base station includes the steps of, at the base station, detecting a direction in which the user equipment is located, transmitting precoded reference signals toward the detected direction by spatial multiplexing using same frequency and time resources, and determining a beam for the user equipment based upon feedback information from the user equipment

Radio base station, user terminal, and transmission power control method

Abstract: The present invention is designed to enable uplink signal transmission power control that is suitable when non-orthogonal multiple access (NOMA) is used on the uplink. The radio base station of the present invention has a decision section that decides whether or not to non-orthogonal-multiplex uplink signals of a plurality of user terminals, a transmission section that transmits, to a user terminal, switching information to command a switch to one of a first transmission power control method, which is used when the uplink signals are non-orthogonal-multiplexed, and a second transmission power control method, which is used when the uplink signals are not non-orthogonal-multiplexed, based on the decision in the decision section, and transmission power determining information, which is used to determine transmission power of the uplink signal, and a receiving section that receives the uplink signal with transmission power that is determined based on the switching information and the transmission power determining information.

Degrees of Freedom Characterization: The 3-User SISO Interference Channel with Blind Interference Alignment

Abstract: We characterize the degrees of freedom (DoF) of the 3-user Gaussian interference channel where each transmitter is equipped with a single conventional antenna and each receiver is equipped with one multi-mode antenna. By assuming that the channel is unknown to the transmitters and only known to the receivers, we show that by using linear blind interference alignment (BIA) with antenna switching at the receivers only, the sum DoF are \frac{6}{5}. The new insight behind this result is that any vector of a user aligned at one unintended receiver cannot be aligned at the other unintended receiver. This is the first complete characterization of the sum DoF when using BIA over the Gaussian Interference Channel. The DoF result under the temporal correlated channels is also discussed.