摘要:
A method and apparatus is disclosed herein for transmitting data in a network (e.g., a relay network). In one embodiment, the method comprises performing pre-transmission of a packet to hops to enable the base station and the plurality of hops to transmit the packet synchronously to one or more mobile stations in the wireless communication system; and performing one or more re-transmissions of the packet at a first set of one or more hops in the system during a delay due to pre-transmissions at a second set of one or more hops in the system.
摘要:
A linear least squares (LLS) estimator provides a low complexity estimation of the location of a mobile terminal (MT), using one of the fixed terminals (FTs) as a reference FT to derive a linear model. A method for selecting a reference FT is disclosed, which improves the location accuracy relative to an arbitrary approach to selecting the reference FT. In addition, a covariance-matrix based LLS estimator is proposed in line-of-sight (LOS) and non-LOS (NLOS) environments to further provide accuracy, taking advantage of the correlation of the observations. Different techniques for selecting the reference FT under non-LOS (NLOS) conditions are disclosed. A map-based two-stage LLS estimator assists in selecting the reference FT under NLOS conditions.
摘要:
A base station (BS) communicates with a mobile station (MS) through relay stations (RSs). In one exemplary reliable relay-associated transmission scheme, the BS transmits data to the RSs using multicast or unicast. From the received packets, each RS calculates its reliability value according to a reliability function, which it informs the MS. The BS then generates a reliability metric to identify the RSs that are considered reliable. The reliable RSs transmit their information to the MS under a cooperative multicast transmission mode. Meanwhile, the unreliable RSs overhear the transmissions between the reliable RSs and the target MS. If the MS is unable to receive information from reliable RSs, the unreliable RSs can join the cooperative transmission to provide a higher cooperative diversity gain to the target MS.
摘要:
In a geolocation application, a method is provided to jointly estimate the time-of-arrival (TOA) and the amplitude of a received signal based on super-resolution technique. The super-resolution joint TOA-amplitude estimators are provided based on either the expectation-maximization (EM), parallel-interference-cancellation space-alternating generalized expectation maximization (PIC-SAGE) or serial-interference-cancellation SAGE (SIC-SAGE). The SIC-SAGE estimator minimizes the ranging estimation error especially under a non-line-of-sight (NLOS) condition. The SIC-SAGE estimator is a simplified version of the maximum likelihood estimator with more stable performance in a multipath rich environment, such as the ultra-wideband (UWB) based applications. These techniques provide the following benefits: 1) it is generic, so that signal processing can be deployed on both time-domain (e.g., UWB impulse-radio) and frequency-domain (e.g., multi-band orthogonal frequency-division multiplexing (MB-OFDM)) based transceiver schemes and applicable for both UWB and non-UWB systems; 2) it is robust especially under NLOS condition and multipath rich environment.
摘要:
The following invention relates to geolocation technology. In particular, the proposed method can be used to determine the optimum threshold value that minimizes the estimation error. The proposed method also allows the threshold value to be varied adaptively according to the signal-to-noise ratios (SNRs) under consideration. This is to ensure that the optimum threshold value is being selected under all channel conditions i.e., both line-of-sight (LOS) and non-LOS (NLOS) scenarios. Additionally, the proposed method is generic and system independent in which it can be applied to both coherent (e.g., match filter (MF)) and non-coherent receivers (e.g., energy detector (ED)).
摘要:
A system and method for using subnet relations to determine paging areas, for performing authentication and association, and to activate access network interfaces in wireless communication devices in a heterogeneous access network. Paging areas are generated using subnet relations by determining mobility agent servers within a predetermined number of subnet relations from a last active mobility agent server. Authentication and association are also accomplished using subnet relations. Access network interfaces can also be turned on and off based on subnet relations thereby conserving battery power.
摘要:
Apparatuses and methods are disclosed herein for implementing dormant mode with paging in a WLAN. Power savings in the computing device and reduction in traffic across the network are achieved by requiring a computing device to inform the WLAN of its location only when it crosses a paging area boundary or is to receive IP traffic. Dormant mode with paging is implemented in a protocol that supports dormant functionality and paging functionality but does not itself provide methods or standards for implementing such functionality, such as the IEEE 802.11. The methods and apparatuses disclosed herein provide the methods needed to implement dormant mode with paging in such a protocol. Generally, the methods and apparatuses for implementing dormant mode with paging basically include (1) establishing paging areas; (2) communicating access group information to a computing device; and (3) locating a computing device.
摘要:
A method for power saving in an ad hoc wireless computer network determines an optimal ATIM message exchange window. The method (a) determines an effective number of nodes that participate in exchanges of ATIM messages during an ATIM window; (b) using the effective number of nodes, calculating a length for a data frame transmission window; and (c) calculates a length for the ATIM window using the calculated data frame transmission window. In one instance, the method determines the effective number of nodes based on the number of senders of ATIM messages. In another instance, the effective number of nodes is determined based on both senders and recipients of the ATIM messages. The method may determine the effective number of nodes from a number of successful ATIM message transmissions in a given time period. The calculated ATIM window size can be provided as an initial value to other methods that dynamically adjust the ATIM window size.
摘要:
Methods are disclosed to support power saving states of a beacon station in an ad hoc wireless local area network (WLAN). Some of the methods allow exchanging power management information among stations in the wireless network and to allow beacon station handovers. In some methods, always-on stations are given a higher priority to become a beacon station or a beacon station handover destination. The methods achieve good power saving while minimizing beacon handover frequency.
摘要:
A method supports scalable and reliable multicast in a wireless network with a large bandwidth-delay product. In this method, acknowledgement packets from different receivers experiencing the same number of data packets lost are assigned the same time slots. This method can be combined with other loss recovery techniques, such as forward error correction (FEC) recovery, proactive protection, feedback suppression and collision detection. Scalability is achieved as bandwidth usage relates only to the number of packets transmitted, rather than the number of receivers.