Wireless Communications

A cellular base station serves a multiplicity of single-antenna terminals over the same time-frequency interval. Time-division duplex operation combined with reverse-link pilots enables the base station to estimate the reciprocal forward- and reverse-link channels. The conjugate-transpose of the channel estimates are used as a linear precoder and combiner respectively on the forward and reverse links. Propagation, unknown to both terminals and base station, comprises fast fading, log-normal shadow fading, and geometric attenuation. In the limit of an infinite number of antennas a complete multi-cellular analysis, which accounts for inter-cellular interference and the overhead and errors associated with channel-state information, yields a number of mathematically exact conclusions and points to a desirable direction towards which cellular wireless could evolve. In particular the effects of uncorrelated noise and fast fading vanish, throughput and the number of terminals are independent of the size of the cells, spectral efficiency is independent of bandwidth, and the required transmitted energy per bit vanishes. The only remaining impairment is inter-cellular interference caused by re-use of the pilot sequences in other cells (pilot contamination) which does not vanish with unlimited number of antennas.

Noncooperative Cellular Wireless with Unlimited Numbers of Base Station Antennas

Multiple-input multiple-output (MIMO) technology is maturing and is being incorporated into emerging wireless broadband standards like long-term evolution (LTE) [1]. For example, the LTE standard allows for up to eight antenna ports at the base station. Basically, the more antennas the transmitter/receiver is equipped with, and the more degrees of freedom that the propagation channel can provide, the better the performance in terms of data rate or link reliability. More precisely, on a quasi static channel where a code word spans across only one time and frequency coherence interval, the reliability of a point-to-point MIMO link scales according to Prob(link outage) ` SNR-ntnr where nt and nr are the numbers of transmit and receive antennas, respectively, and signal-to-noise ratio is denoted by SNR. On a channel that varies rapidly as a function of time and frequency, and where circumstances permit coding across many channel coherence intervals, the achievable rate scales as min(nt, nr) log(1 + SNR). The gains in multiuser systems are even more impressive, because such systems offer the possibility to transmit simultaneously to several users and the flexibility to select what users to schedule for reception at any given point in time [2].

/pdf/scaling-up-mimo-opportunities-and-challenges-with-very-large-puqp9v7gzk.pdf

Scaling Up MIMO: Opportunities and Challenges with Very Large Arrays

The quintessential goal of sensor array signal processing is the estimation of parameters by fusing temporal and spatial information, captured via sampling a wavefield with a set of judiciously placed antenna sensors. The wavefield is assumed to be generated by a finite number of emitters, and contains information about signal parameters characterizing the emitters. A review of the area of array processing is given. The focus is on parameter estimation methods, and many relevant problems are only briefly mentioned. We emphasize the relatively more recent subspace-based methods in relation to beamforming. The article consists of background material and of the basic problem formulation. Then we introduce spectral-based algorithmic solutions to the signal parameter estimation problem. We contrast these suboptimal solutions to parametric methods. Techniques derived from maximum likelihood principles as well as geometric arguments are covered. Later, a number of more specialized research topics are briefly reviewed. Then, we look at a number of real-world problems for which sensor array processing methods have been applied. We also include an example with real experimental data involving closely spaced emitters and highly correlated signals, as well as a manufacturing application example.

Two decades of array signal processing research: the parametric approach

It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity. >

On the capacity of a cellular CDMA system

네트워크에서 다수의 뉴머롤로지들을 인에이블 하는 방법을 제시한다. 이 방법은, 유저 장비(UE)에 의해 수행되되, 제1 뉴머롤로지를 갖는 방송 채널상에서 제1 탐색 공간에서의 시스템 정보를 수신하는 단계(S110)와, 상기 수신된 시스템 정보로부터 제2 탐색 공간을 결정하는 단계(S120)와, 제2 뉴머롤로지를 갖는 상기 제2 탐색 공간에서의 또 다른 정보를 수신하는 단계(S130)를 포함한다. UE, 기지국, 컴퓨터 프로그램 및 컴퓨터 프로그램 제품도 제시된다.

네트워크에서 다수의 뉴머롤로지의 인에이블링

Techniques for selecting and utilizing one or more novel symbol structures, control signaling, and scheduling for wireless signal transmission/reception are presented. An example method is presented that includes determining (302), based on control information corresponding to a slot, that a user equipment (UE) (102A) or another UE (102B) in communication with a network node (106) is to transmit acknowledgement (ACK) or negative acknowledgement (NACK) feedback in the slot for a downlink signal received by the UE (102A) or the other UE (102B) in the slot. In addition, the example method includes transmitting (304) an intermediate uplink signal to the network node (106) and/or receiving an intermediate downlink signal from the network node (106) after the downlink signal is fully received and before transmission of the ACK or NACK feedback begins. Example apparatuses, such as UEs and network nodes, and computer programs/code are also presented.

Receiver-specific transmission length

The present invention generally relates to radio communication systems, relay nodes, controller nodes, user equipment (user terminals), software and methods for said systems and nodes. In one embodiment, a method for operating a control node for a wireless communication system is provided. The method comprises the steps: creating a data frame comprising an early part and a later part, wherein the early part comprises first control data for controlling a receiving node; checking whether second control data are to be put into the later part; scheduling payload data for the receiving node into the later part if second control data are not to be put into the later part; and transmitting the data frame to the receiving node.

Method and nodes for relay in a radio communication system

The invention discloses a method for a cellular communications system, in which traffic is sent in frames, each frame comprising a first number of subframes, with a second number of said subframes being available for at least either uplink or downlink traffic. At least one of said second number of subframes is made to comprise at least three parts, as follows: One part which is utilized for uplink traffic,One part which is utilized for downlink traffic,One part which is utilized as a guard period, with said guard period part being scheduled between the uplink and the downlink parts. The duration of at least two of said three parts may be varied to fit the current system need.

***WITHDRAWN PATENT AS PER THE LATEST USPTO WITHDRAWN LIST***TDD time slot splitting

More than one set of sounding signal configuration parameters are determined for the same mobile terminal. The mobile terminal uses the sets of configuration parameters to generate different sounding reference signals which can be used for different purposes such as estimating timing and channel quality. In one embodiment, a method of configuring uplink sounding transmissions by mobile terminals in a wireless communication network is characterized by determining different sets of configuration parameters for sounding signal transmissions for a given mobile terminal (200). The different sets of configuration parameters are transmitted to the mobile terminal, allowing the mobile terminal to generate different sounding signals for different uses by the wireless communication network (202).

Stefan Parkvall

Papers

네트워크에서 다수의 뉴머롤로지의 인에이블링

Receiver-specific transmission length

Method and nodes for relay in a radio communication system

WITHDRAWN PATENT AS PER THE LATEST USPTO WITHDRAWN LISTTDD time slot splitting

Channel sounding using multiple sounding signal configurations