Fractional programming (FP) refers to a family of optimization problems that involve ratio term(s). This two-part paper explores the use of FP in the design and optimization of communication systems. Part I of this paper focuses on FP theory and on solving continuous problems. The main theoretical contribution is a novel quadratic transform technique for tackling the multiple-ratio concave–convex FP problem—in contrast to conventional FP techniques that mostly can only deal with the single-ratio or the max-min-ratio case. Multiple-ratio FP problems are important for the optimization of communication networks, because system-level design often involves multiple signal-to-interference-plus-noise ratio terms. This paper considers the applications of FP to solving continuous problems in communication system design, particularly for power control, beamforming, and energy efficiency maximization. These application cases illustrate that the proposed quadratic transform can greatly facilitate the optimization involving ratios by recasting the original nonconvex problem as a sequence of convex problems. This FP-based problem reformulation gives rise to an efficient iterative optimization algorithm with provable convergence to a stationary point. The paper further demonstrates close connections between the proposed FP approach and other well-known algorithms in the literature, such as the fixed-point iteration and the weighted minimum mean-square-error beamforming. The optimization of discrete problems is discussed in Part II of this paper.

Fractional Programming for Communication Systems—Part I: Power Control and Beamforming

Surface acoustic waves are propagated in a lower-left oblique direction and a lower-right oblique direction from an excitation element located on the upper side of a non-piezoelectric substrate and then received by receiving elements located on the left side and the right side, while surface acoustic waves are propagated in an upper-left oblique direction and an upper-right oblique direction from an excitation element located on the lower side of the non-piezoelectric substrate and then received by the receiving elements located on the left side and the right side. Based on the received results at the two receiving elements, a position of an object in contact with the non-piezoelectric substrate is detected. The sensitivity in a region near the diagonal, which is influenced largely by propagation loss of the surface acoustic waves, is improved by increasing the widths of the electrode fingers of the excitation elements and/or the receiving elements, the number of pairs of the electrode fingers, or the aperture width of comb-like electrodes, according to an increase in the propagation distances of the surface acoustic waves, i.e., toward the region near the diagonal.

Touch panel device

Today, acoustic filters are the filter technology to meet the requirements with respect to performance dictated by the cellular phone standards and their form factor. Around two billion cellular phones are sold every year, and smart phones are of a very high percentage of approximately two-thirds. Smart phones require a very high number of filter functions ranging from the low double-digit range up to almost triple digit numbers in the near future. In the frequency range up to 1 GHz, surface acoustic wave (SAW) filters are almost exclusively employed, while in the higher frequency range, bulk acoustic wave (BAW) and SAW filters are competing for their shares. Prerequisites for the success of acoustic filters were the availability of high-quality substrates, advanced and highly reproducible fabrication technologies, optimum filter techniques, precise simulation software, and advanced design tools that allow the fast and efficient design according to customer specifications. This paper will try to focus on innovations leading to high volume applications of intermediate frequency (IF) and radio frequency (RF) acoustic filters, e.g., TV IF filters, IF filters for cellular phones, and SAW/BAW RF filters for the RF front-end of cellular phones.

Acoustic Wave Filter Technology–A Review

A system that incorporates the subject disclosure may perform, for example, a method for receiving interference information, identifying a plurality of interferers, approximating a location of the plurality of interferers, and adjusting an antenna pattern of an antenna. The method can include determining traffic loads and adjusting the antenna pattern according to the traffic loads. Other embodiments are disclosed.

Method and apparatus for interference mitigation utilizing antenna pattern adjustments

This application discloses methods for creating self-organizing networks implemented on heterogeneous mesh networks. The self-organizing networks can include a computing cloud component coupled to the heterogeneous mesh network. In the methods and computer-readable mediums disclosed herein, a processor receives an environmental condition for a mesh network. The processor may have measured the environmental condition, or it could have received it from elsewhere, e.g., internally stored information, a neighboring node, a server located in a computing cloud, a network element, user equipment (“UE”), and the like. After receiving the environmental condition, the processor evaluates it and determines whether an operational parameter within the mesh network should change to better optimize network performance.

Heterogeneous self-organizing network for access and backhaul

Acoustic resonators such as surface acoustic wave (SAW) devices and thin film bulk acoustic resonators (FBAR) can be configured to produce a band reject filter. Such a filter overcomes the insertion loss and power handling limitations of conventional band pass configurations and as such can be used in power amplifier and duplexer applications.

Band reject filters

A system, method, and software are provided for measuring co-channel interference in a wireless network with particular application for management of resource allocation for Non Line of Sight (NLOS) wireless backhaul in MicroCell and PicoCell networks. Given the difficulty of predicting the mutual interference between multiple links, DownLink and UpLink co-channel interference are characterized between each Hub and each Remote Backhaul Module Unit periodically during active service. Beneficially, the co-channel interference metrics are used as the basis for intelligently and adaptively managing network resources to substantially reduce interference and increase the aggregate data capacity of the network e.g. by grouping of interfering and/or non-interfering links, and managing resource block allocations accordingly, i.e. assigning common resource blocks preferentially to weakly interfering links or groups of links and allocating different resource blocks or orthogonal channels to strongly interfering links or groups of links.

System and method for co-channel interference measurement and managed adaptive resource allocation for wireless backhaul

A feed forward power amplifier has a main amplifier and an error compensation path that compares the input and output of the main amplifier and subsequently adjusts the output signal from the main amplifier. Currently, such a design requires the implementation of a delay apparatus to delay the output of the main amplifier in order to compensate for the delay within the error compensation path. This delay apparatus implemented within a high-power area costs the power amplifier in terms of money, size, and/or efficiency. With the implementation of a phase compensation filter within the error compensation path, the delay apparatus can be removed. The phase compensation filter has a frequency versus phase characteristic with a positive slope for a limited bandwidth and a constant frequency versus gain characteristic. This allows, for the limited bandwidth, the characteristic of the error compensation path to be similar to that of the undelayed output of the main amplifier. The use of a phase compensation filter within a feedback power amplifier can also have benefits, as the bandwidth of the power amplifier can be expanded.

Error correction within power amplifiers

Systems and Methods are provided for relaying wireless signals bi-directionally between user equipment (UE) and base station transceivers (BTS). Various slot types are defined during which a relay node takes on the personality of either the UE or the BTS. In order to implement the relay node with a single transceiver chain, a first switching matrix is used to switch high band and low band RF bandpass filters between receive and transmit paths, and a second switching matrix is used to switch two frequency sources between the receive and transmit path. In this way, a single receive path can function both in the UE and BTS personality, as can the single transmit path.

Method and apparatus for relaying a wireless signal

A reference timing signal apparatus with a phase-locked loop has a computer algorithm which adaptively models the multiple frequencies of an oscillator following a training period. The oscillation frequency of the oscillator is controlled in response to a phase detector output. The computer algorithm processes the control signal applied to the oscillator. The computer algorithm updates the characteristics of the model relating to the aging and temperature of the oscillator, using for example, a Kalman filter as an adaptive filter. By the algorithm, the subsequent model predicts the future frequency state of the oscillator on which it was trained. The predicted frequency of the model functions as a reference to correct the frequency of the oscillator in the event that no input reference timing signal is available. In a case of using pre-processing infinite impulse response filters (IIRFs) before the adaptive processor, the time delay caused by the filters are compensated after the adaptive processor. Without pre-processing IIRFs, aging and temperature update rates are adaptively controlled by dynamically changing the rates depending upon the loop condition to achieve a wider tracking bandwidth. With the model updating algorithm, oscillators of low stability performance may be used as cellular base station reference oscillator.

Steve Beaudin

Papers

Band reject filters

System and method for co-channel interference measurement and managed adaptive resource allocation for wireless backhaul

Error correction within power amplifiers

Method and apparatus for relaying a wireless signal

Reference timing signal apparatus and method