Huawei

About: Huawei is a company organization based out in Shenzhen, China. It is known for research contribution in the topics: Terminal (electronics) & Node (networking). The organization has 41417 authors who have published 44698 publications receiving 343496 citations. The organization is also known as: Huawei Technologies & Huawei Technologies Co., Ltd..

Isolation-Improved Dual-Band MIMO Antenna Array for LTE/WiMAX Mobile Terminals

Abstract: A compact dual-band multiple-input–multiple-output (MIMO) antenna array with eight elements is proposed for the Long Term Evolution (LTE)/Worldwide Interoperability for Microwave Access (WiMAX) mobile applications. The dual-band MIMO array consists of four U-slit etched planar inverse-F antennas (PIFAs) and four L-slit etched PIFAs. The two types of PIFAs are placed orthogonally to reduce mutual coupling between them. With the presented decoupling methods in the design including the disconnection of ground plane, the parasitic resonant strips, and also the modified PIFAs, the excellent element isolation (above 20 dB) and other good MIMO performance are achieved. The overall dimension of the MIMO system is only 140 $\,\times\,$ 70 $\, \times\,$ 9.55 mm $^{3}$ , and good return loss (above 10 dB) is achieved across the operating bands (2.6–2.8 and 3.4–3.6 GHz) for all the PIFA elements. The radiation patterns and envelope correlation coefficient (ECC) of MIMO system are also studied, showing quasi-omnidirectional radiation and accepted envelope correlation coefficient across the dual-band operation for mobile communications.

Spectrum leasing to femto service provider with hybrid access

Abstract: The concept of femtocell that operates in licensed spectrum to provide home coverage has attracted interest in the wireless industry due to high spatial reuse, and extensive deployments of femtocells is expected in the future. In this paper, we consider the scenario that a femtocell service provider (FSP) expects to rent spectrum from the coexisting macrocell service provider (MSP) to serve its end users. In addition to the spectrum leasing payment, the FSP may allow hybrid access of macrocell users to improve the utilities of itself and MSP, which are defined as the sum of data traffic and payment/revenue. We propose the spectrum leasing framework taking hybrid access into consideration. The whole procedure is modeled as a three-stage Stackelberg game, where MSP and FSP determine the spectrum leasing ratio, spectrum leasing price and open access ratio sequentially to maximize their utilities, and the existence of the Nash Equilibrium of the sequential game is analyzed. We characterize the equilibrium, in terms of access price, spectrum acquisition of FSP, the open access ratio, and price of anarchy via simulation. Numerical results show that both MSP and FSP can benefit from spectrum leasing, and hybrid access of femtocell can further improve their utilities, which provide sufficient incentive for their cooperation.

Location Based Beamforming in 5G Ultra-Dense Networks

Abstract: In this paper we consider transmit (Tx) and receive (Rx) beamforming schemes based on the location of the device. In particular, we propose a design methodology for the Tx/Rx beamforming weight-vectors that is based on the departure and arrival angles of the line-of sight (LoS) path between accessnodes (ANds) and user-nodes (UNds). A network-centric extended Kalman filter (EKF) is also proposed for estimating and tracking the directional parameters needed for designing the Tx and Rx beamforming weights. The proposed approach is particularly useful in 5G ultra-dense networks (UDNs) since the high-probability of LoS condition makes it possible to design geometric beams at both Tx and Rx in order to increase the signal-to-interferenceplus- noise ratio (SINR). Moreover, relying on the location of the UNd relative to the ANds makes it possible to replace fullband uplink (UL) reference signals, commonly employed for acquiring the channel-state- information-at-transmitter (CSIT) in time- division-duplex (TDD) systems, by narrowband UL pilots. Also, employing the EKF for tracking the double-directional parameters of the LoS-path allows one to reduce the rate at which UL reference signals are transmitted. Consequently, savings in terms of time frequency resources are achieved compared to beamforming schemes based on full-band CSI. Extensive numerical results are included using a realistic ray-tracing based system-level simulator in ultra-dense 5G network context. Results show that position based beamforming schemes outperform those based on full-band CSI in terms of mean user-throughput even for highly mobile users.

Prefix search circuitry and method

Abstract: Prefix searches for directing internet data packets are performed in a prefix search integrated circuit. The integrated circuit includes an array of search engines, each of which accesses a prefix search tree data structure to process a prefix search. An SDRAM is dedicated to each search engine, and SDRAMs share address and control pins to plural search engines on the IC chip. Internal nodes of the tree data structure are duplicated across banks of the SDRAMs to increase bandwidth, and leaf nodes are stored across the SDRAM banks to reduce storage requirements. Within each search engine, data stored in a data register from an SDRAM is compared to a prefix search key stored in a key register. Based on that comparison, an address is calculated to access further tree structure data from the SDRAM. Packet descriptors containing search keys are forwarded to the search engines from an input queue and the search results are forwarded to an output queue, the same packet order being maintained in the two queues.

Secrecy Outage Analysis Over Correlated Composite Nakagami- $m$ /Gamma Fading Channels

Abstract: The secrecy systems operating over spatially correlated composite fading channels is analyzed in this letter. We adopt a multiplicative composite channel model for both the legitimate communication link and the link between the eavesdropper and the legitimate transmitter, consisting of Nakagami- $m$ distributed small-scale fading and shadowing (large-scale fading) modeled by the Gamma distribution. We consider the realistic case where small-scale fading between the links is independent, but shadowing is arbitrarily correlated, and present novel analytical expressions for the probability that the secrecy capacity falls below a target secrecy rate. The presented numerically evaluated results, verified by equivalent computer simulations, offer useful insights on the impact of the shadowing correlation and composite fading parameters on the system’s secrecy outage performance.