Abstract: A method and a receiver are provided for demodulating a received multi-carrier modulated signal. The demodulation procedure includes (a) multiplying the received multi-carrier modulated signal with its complex conjugate to obtain a squared signal; (b) multiplying the squared signal with a carrier demodulating signal to obtain a product signal, and integrating the product signal over the duration T. A bit decision may then be performed on the integration result using analog components without the need for high-speed analog-to-digital conversion.

Abstract: 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.

Abstract: A non-cyclic evolving-type user resource structure applicable for use in the uplink and the downlink of an OFDMA system with large null guard tones (e.g., a 3GPP LTE system) is provided. In one example, the user resource structure combines the benefits of localized and distributed types of resource structures available in the current baseline 3GPP LTE (Release 8) specifications, and is especially suitable for operating in a fast time-varying channel. In another example, the non-cyclic evolving-type resource structure may be simplified to have no more than three stages: a band-type first stage, a partially evolved-type second stage and an interleaved-type third stage. Depending upon the target or average mobile speed and packet length, the resource structure may even have less than three stages.

Abstract: 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.

Abstract: An evolving-type resource structure supports high data rate services at high mobile speeds. The evolving-type resource structure is an efficient diversity-exploiting user resource structure for fast time-varying frequency-selective fading channel environments. In one example, an evolving-type resource structure takes advantages of both band-type and interleaved-type structures which exploit both multiuser diversity and frequency diversity in fast time-varying channels. The evolving-type resource structure is applicable to centralized, semi-distributed and distributed access schemes and may be used in both downlink (DL) and uplink (UL) transmissions in a cellular system.

Abstract: Methods and apparatuses are disclosed herein for population tracking, counting and/or movement estimation. In one embodiment, the method comprises receiving mobile phone operational data indicative of user equipment location, where the event data includes location area update messages and periodic registration messages; and performing travel estimation based on the mobile phone operation data, including performing interpolation on data associated with one or more individuals in a population to estimate intermediate positions of a trajectory of each of the one or more individuals for a specified time period based on a shortest path mesh sequence estimation algorithm.

Abstract: Methods and apparatuses are disclosed herein for population tracking, counting and/or movement estimation. In one embodiment, the method comprises receiving mobile phone operational data indicative of user equipment location, where the event data includes location area update messages and periodic registration messages; and performing travel estimation based on the mobile phone operation data, including performing interpolation on data associated with one or more individuals in a population to estimate intermediate positions of a trajectory of each of the one or more individuals for a specified time period based on a shortest path mesh sequence estimation algorithm.

Abstract: Methods and apparatuses are disclosed herein for population tracking, counting and/or movement estimation. In one embodiment, the method comprises receiving mobile phone operational data indicative of user equipment location, where the event data includes location area update messages and periodic registration messages; and performing travel estimation based on the mobile phone operation data, including performing interpolation on data associated with one or more individuals in a population to estimate intermediate positions of a trajectory of each of the one or more individuals for a specified time period based on a shortest path mesh sequence estimation algorithm.

Abstract: A method and apparatus is disclosed herein for estimating travel behavior in a mobile network. In one embodiment, the method comprises receiving event data indicative of user equipment location, pre-processing received event data to produce pre-processed data, performing straight line interpolation on pre-processed data of one or more individuals in the population to estimate intermediate positions of a trajectory of each of the one or more individuals from a first position to a second position, and counting a number of individuals in population at a given time and at a given area.

Abstract: A method and apparatus is disclosed herein for synchronized multi-link transmission in an ARQ-enabled multi-hop wireless network. In one embodiment, the method comprises performing pre-transmission of a packet to hops to enable a base station and the plurality of hops in the network 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 set of one or more hops forming a path in the network if time remaining before a synchronized transmission time for the path as a whole is greater than a threshold.

Abstract: In a fast active scanning wireless network apparatus and method for quick determination of available access points (20), information about a candidate set of available access points (20) is obtained, and a candidate access point is identified from the candidate set. A mobile station (10) then queries the candidate access point with a probe request that designates the candidate access point as a sole responder. The probe request prevents other access points from contending for the medium of communication between the mobile station and the designated sole responder access point by excluding the attempt by other access points (20) to transmit probe responses. The apparatus and method thus increases the probability of a fast and successful probe request from the mobile station and subsequent response from the designated access point (20). The designated access point may also respond with a probe response of high priority, preventing intervention of communication.

Abstract: A mobile communication system uses a multiple-input-multiple-output (MIMO) technology with an orthogonal frequency division multiplexing access (OFDMA) scheme. At network entry, an initial ranging method selects from multiple ranging signal designs to accomplish the initial ranging process. Three classes of ranging signal designs may be selected for use in generating ranging codes. The information on the ranging signal design to be used, which is selected by the base station based on the cell size of the communication system (i.e., the radio coverage area of the base station), is broadcast from the BS. The ranging signal designs are directly applicable to single-antenna systems, and they are applied to MIMO systems by using appropriate mapping across transmit antennas based on the adopted MIMO ranging transmission scheme. Optimum eigenmode and suboptimum eigenmode transmission schemes provide the best performance at high computational complexity and high power consumption.

Abstract: A cooperative communication scheme is provided for a base station (BS) to communicate with a mobile station (MS) through a group of relay stations (RSs). The RSs, collectively referred to as a relay-associated group of RSs (R-group), serve the same target MS. The R-group may be formed during initial ranging or during periodical ranging of the MSs, according to the channel conditions between the MSs and the RSs. A reliable relay-associated transmission scheme provides fast recovery and reduces the burden on the BS. In one exemplary scheme, the BS transmits data to the R-group. To ensure that reliable transmission exists between the BS and the R-group, the BS initially sends the information to all the RSs in the R-group using multicast or unicast mode.

Abstract: Co-channel macrocell users will inherently produce co-channel interference at a nearby femtocell base station. To reduce the peak co-channel interference power, the femtocell users adjust their symbol timing with regard to the macrocell users so as to maximize a spreading of the co-channel interference spectrum. In this fashion, the peak co-channel interference power is reduced, thereby leading to improved bit error rates for the femtocell users.

Abstract: Active scanning method in a wireless network for fast determining available access points (106, 806) using inter-AP (Access Point) communication is described. In the scanning method, a mobile station (102, 802) sends Probe Request for Proxy frame to the current AP (104, 804) serving the mobile station (102, 802). In response to the Probe Request for Proxy frame, the current AP (104, 804) send Proxy Probe Request packet to the appropriate APs (106, 806). In response to the Proxy Probe Request packet, the neighbor APs (106, 806) send Probe Response frame to the mobile station (102, 802) on its operating channel. Since the mobile station (102, 802) moves to the channel being examined after sending the Probe Request for Proxy frame, it receives the Probe Response frame if it is in the coverage area of the neighbor AP (106, 806). The content of Probe Response frame provides the mobile station (102, 802) with the information to be used in handoff decision and network join procedures.

Abstract: Systems and methods are provided for a distributed inter-cell interference avoidance (ICIA) technique for avoiding co-channel interference between femtocell networks and macrocell networks. At the macrocell, user equipments sense the downlink (DL) spectrum and detects whether there are any nearby interfering femtocells. If there is any interference, a macrocell base station appropriately re-schedules the DL resources and also uses a mapping function to re-schedule uplink (UL) resources based on the re-scheduled DL resources. At the femtocell, a femtocell base station senses the UL spectrum to detect for interference from nearby macrocell users. If there is interference, femtocell gives priority for use of the resources to the macrocell by releasing UL resources. Femtocell may also use the same mapping function to obtain the DL resources used by the macrocell and to re-schedule DL and UL resources of the femtocell to avoid using the DL and UL resources of the macrocell.

Abstract: 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.

Abstract: A cooperative communication scheme is provided for a base station (BS) to communicate with a mobile station (MS) through a group of relay stations (RSs). The RSs, collectively referred to as a relay-associated group of RSs (R-group), serve the same target MS. The R-group may be formed during initial ranging or during periodical ranging of the MSs, according to the channel conditions between the MSs and the RSs. A reliable relay-associated transmission scheme provides fast recovery and reduces the burden on the BS. In one exemplary scheme, the BS transmits data to the R-group. To ensure that reliable transmission exists between the BS and the R-group, the BS initially sends the information to all the RSs in the R-group using multicast or unicast mode.

Abstract: 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.

Abstract: In a wireless communication system including a base station and multiple mobile stations, a method transmits an orthogonal frequency division multiple access (OFDMA) data frame to the mobile stations. The method includes the steps of (a) at the beginning of the data frame, collecting metrics representing channel conditions for each of the channels; (b) assigning each mobile station to one or more communication channels based on the metrics collected; (c) for each symbol in the frame, calculating an average bit-error-rate for each of a number of transmission modes, and assigning to that symbol the transmission mode corresponding to the lowest calculated average bit-error-rate for that symbol; and (d) transmitting the symbols in the frame according to their respective assigned transmission mode. In addition, a bit-loading optimization step may be carried out in conjunction with the method to determine a modulation order for each symbol to be transmitted.