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Showing papers by "Qualcomm published in 2004"


Journal ArticleDOI
08 Nov 2004
TL;DR: An overview of MIMO wireless technology covering channel models, performance limits, coding, and transceiver design is provided, in principle, to meet the 1 Gb/s data rate requirement with a single-transmit single-receive antenna wireless system.
Abstract: High data rate wireless communications, nearing 1 Gb/s transmission rates, is of interest in emerging wireless local area networks and home audio/visual networks. Designing very high speed wireless links that offer good quality-of-service and range capability in non-line-of-sight (NLOS) environments constitutes a significant research and engineering challenge. Ignoring fading in NLOS environments, we can, in principle, meet the 1 Gb/s data rate requirement with a single-transmit single-receive antenna wireless system if the product of bandwidth (measured in hertz) and spectral efficiency (measured in bits per second per hertz) is equal to 10/sup 9/. A variety of cost, technology and regulatory constraints make such a brute force solution unattractive, if not impossible. The use of multiple antennas at transmitter and receiver, popularly known as multiple-input multiple-output (MIMO) wireless, is an emerging cost-effective technology that offers substantial leverages in making 1 Gb/s wireless links a reality. The paper provides an overview of MIMO wireless technology covering channel models, performance limits, coding, and transceiver design.

2,154 citations


Patent
24 Feb 2004
TL;DR: In this paper, a cellular network may provide an advertisement for a WLAN, such as in an overhead signaling message, and the advertisement may identify the Access Point(s) by an Extended Service Set Identifier (ESSID), the remote station may then scan for the WLAN service automatically or manually.
Abstract: Method and apparatus for detection and selection of Wireless Local Area Network (WLAN) service. A cellular network may provide an advertisement for a WLAN, such as in an overhead signaling message. The advertisement may identify the Access Point(s) by an Extended Service Set Identifier (ESSID). The remote station may then scan for the WLAN service automatically or manually.

487 citations


Patent
28 Jun 2004
TL;DR: In this paper, a mobile station uses wireless signals from a plurality of wireless networks for position determination (e.g., for data communication, for obtaining time and/or frequency information, for range measurement, for sector or altitude estimation).
Abstract: Methods and apparatuses for position determination and other operations. In one embodiment of the present invention, a mobile station uses wireless signals from a plurality of wireless networks (e.g., with different air interfaces and/or operated by different service providers) for position determination (e.g., for data communication, for obtaining time and/or frequency information, for range measurement, for sector or altitude estimation). In one embodiment of the present invention, mobile stations are used to harvest statistical data about wireless access points (e.g., the locations of mobile stations that have received signals from the wireless access points, such as from cellular base stations, wireless local area network access points, repeaters for positioning signals, or other wireless communication transmitters) and to derive location information (e.g., position and coverage area of the wireless access points) for the wireless networks from the collected statistical data.

375 citations


Journal ArticleDOI
06 Jun 2004
TL;DR: In this paper, a modified derivative-superposition (DS) method was proposed to increase the maximum IIP3 at RF frequencies, which was used in a 0.25mum Si CMOS low-noise amplifier (LNA) designed for cellular code-division multiple access receivers.
Abstract: Intermodulation distortion in field-effect transistors (FETs) at RF frequencies is analyzed using the Volterra-series analysis. The degrading effect of the circuit reactances on the maximum IIP3 in the conventional derivative-superposition (DS) method is explained. The noise performance of this method is also analyzed and the effect of the subthreshold biasing of one of the FETs on the noise figure (NF) is shown. A modified DS method is proposed to increase the maximum IIP3 at RF. It was used in a 0.25-mum Si CMOS low-noise amplifier (LNA) designed for cellular code-division multiple-access receivers. The LNA achieved +22-dBm IIP3 with 15.5-dB gain, 1.65-dB NF, and 9.3 mA@2.6-V power consumption

366 citations


Journal ArticleDOI
08 Nov 2004
TL;DR: This paper adopts spatial diversity as a central theme, and illustrates its benefits across the physical (signal transmission/coding and receiver signal processing) and networking (resource allocation, routing, and applications) layers.
Abstract: The effect of spatial diversity on the throughput and reliability of wireless networks is examined. Spatial diversity is realized through multiple independently fading transmit/receive antenna paths in single-user communication and through independently fading links in multiuser communication. Adopting spatial diversity as a central theme, we start by studying its information-theoretic foundations, then we illustrate its benefits across the physical (signal transmission/coding and receiver signal processing) and networking (resource allocation, routing, and applications) layers. Throughout the paper, we discuss engineering intuition and tradeoffs, emphasizing the strong interactions between the various network functionalities.

326 citations


Patent
Rajiv Vijayan1, Aamod Khandekar1, Fuyun Ling1, Gordon Kent Walker1, Ramaswamy Murali1 
02 Sep 2004
TL;DR: In this paper, a technique for multiplexing and transmitting multiple data streams is described, where each super-frame has a predetermined time duration and is further divided into multiple (e.g., four) frames.
Abstract: Techniques for multiplexing and transmitting multiple data streams are described. Transmission of the multiple data streams occurs in “super-frames”. Each super-frame has a predetermined time duration and is further divided into multiple (e.g., four) frames. Each data block for each data stream is outer encoded to generate a corresponding code block. Each code block is partitioned into multiple subblocks, and each data packet in each code block is inner encoded and modulated to generate modulation symbols for the packet. The multiple subblocks for each code block are transmitted in the multiple frames of the same super-frame, one subblock per frame. Each data stream is allocated a number of transmission units in each super-frame and is assigned specific transmission units to achieve efficient packing. A wireless device can select and receive individual data streams.

289 citations


Patent
15 Oct 2004
TL;DR: In this article, the authors propose a data transmission structure for MAC processing for efficient use of high throughput systems and that may be backward compatible with various types of legacy systems, where frames are transmitted sequentially with no or substantially reduced interframe spacing.
Abstract: Embodiments disclosed herein for MAC processing for efficient use of high throughput systems and that may be backward compatible with various types of legacy systems. In one aspect, a data transmission structure comprises a consolidated poll and one or more frames transmitted in accordance with the consolidated poll. In another aspect, a Time Division Duplexing (TDD) data transmission structure comprises a pilot, a consolidated poll, and zero or more access point to remote station frames in accordance with the consolidated poll. In one aspect, frames are transmitted sequentially with no or substantially reduced interframe spacing. In another aspect, a guard interframe spacing may be introduced between frames transmitted from different sources, or with substantially different power levels. In another aspect, a single preamble is transmitted in association with one or more frames. In another aspect, a block acknowledgement is transmitted subsequent to the transmission of one or more sequential frames.

283 citations


Patent
07 Jan 2004
TL;DR: In this article, pilot interference cancellation is performed to improve performance since subbands used for data transmission by one transmitter may also be used for pilot transmission by another transmitter, and then subtracted from received symbols to obtain pilot-canceled symbols having improved quality.
Abstract: Pilot transmission schemes suitable for use in wireless multi-carrier (e.g., OFDM) communication systems. These pilot transmission schemes may utilize frequency, time, or both frequency and time orthogonality to achieve orthogonality among the pilots transmitted by multiple base stations on the downlink. Frequency orthogonality is achieved by transmitting pilots on disjoint sets of subbands. Time orthogonality is achieved by transmitting pilots using different orthogonal codes (e.g., Walsh codes). The pilots may also be scrambled with different scrambling codes, which are used to randomize pilot interference and to enable identification of the transmitters of these pilots. Pilot interference cancellation may be performed to improve performance since subbands used for data transmission by one transmitter may also be used for pilot transmission by another transmitter. Pilot interference is estimated and then subtracted from received symbols to obtain pilot-canceled symbols having improved quality.

268 citations


Patent
15 Oct 2004
TL;DR: In this article, techniques for MAC processing for efficient use of high throughput systems that is backward compatible with various types of legacy systems are disclosed. But the authors focus on the use of a first signal is transmitted according to a legacy transmission format to reserve a portion of a shared medium, and communication according to another transmission format transpires during the reserved portion.
Abstract: Techniques for MAC processing for efficient use of high throughput systems that is backward compatible with various types of legacy systems are disclosed. In one aspect a first signal is transmitted according to a legacy transmission format to reserve a portion of a shared medium, and communication according to a second transmission format transpires during the reserved portion. In another aspect, a communication device may contend for access on a legacy system, and then communicate according to a new class communication protocol with one or more remote communication devices during the access period. In another aspect, a device may request access to a shared medium according to a legacy protocol, and, upon grant of access, the device may communicate with or facilitate communication between one or more remote stations according to a new protocol.

265 citations


Patent
15 Oct 2004
TL;DR: In this paper, a mobile communications device initiates a handoff from its current base station (BS) sector network attachment point to a new BS sector, e.g., via a network link.
Abstract: A mobile communications device initiates a handoff from its current base station (BS) sector network attachment point to a new BS sector. The mobile sends a handoff request over its current wireless link to the current BS sector, which forwards the request to the new BS sector, e.g., via a network link. The new BS sector processes the request assigning dedicated resources, e.g., an identifier and dedicated uplink segments. Information identifying the allocated resources is conveyed from the new BS sector via the current BS sector to the mobile. The mobile determines the time of the allocated dedicated segments based upon a received beacon signal from the new BS sector with known timing relationships to dedicated segments. The mobile breaks the original wireless link just prior to the time of the first assigned dedicated segment. The mobile communicates information on the assigned dedicated segments to perform registration operations, e.g., timing synchronization and power control, establishing a new wireless link.

259 citations


Patent
15 Oct 2004
TL;DR: In this paper, a data frame is formed comprising a common portion for transmission in a format receivable by various stations, such as access points and remote stations, and a dedicated portion, formatted for transmission to a specified remote station.
Abstract: Techniques for MAC processing for efficient use of high throughput systems that may be backward compatible with various types of legacy systems are disclosed. In one aspect, a data frame is formed comprising a common portion for transmission in a format receivable by various stations, such as access points and remote stations. The data frame also comprises a dedicated portion, formatted for transmission to a specified remote station. In another aspect, the common portion is unsteered, and the dedicated portion is steered. In another aspect, an access point schedules an allocation in response to a data indication included in a common portion of a data frame transmitted from one remote station to another. In another aspect, a first station transmits a reference to a second station, which measures the reference and generates feedback therefrom.

Patent
14 Jun 2004
TL;DR: In this paper, a method for delivering data recovered by a HARQ entity in proper order to higher layers in a CDMA system is presented, where packets are transmitted in a sequential order based on transmission sequence numbers assigned to the packets, and missing packets may be detected based on the TSNs of the received packets.
Abstract: Techniques for delivering data recovered by a HARQ entity in proper order to higher layers in a CDMA system. In a method, packets are received from the HARQ entity by the re-ordering entity and missing packets among the received packets are detected. Packets may be transmitted in a sequential order based on transmission sequence numbers (TSNs) assigned to the packets, and missing packets may be detected based on the TSNs of the received packets. Delivery of received packets later than the missing packets are stalled because higher layers expect data in-order. A determination is thereafter made whether each missing packet is (1) subsequently received from the HARQ entity or (2) lost, by successively eliminating HARQ channels that may be used to send the missing packet. Received packets previously stalled by each missing packet are delivered after the missing packet is determined to be lost or received.

Proceedings ArticleDOI
30 Aug 2004
TL;DR: This work presents a new capacity estimation technique, called CapProbe, which combines delay as well as dispersion measurements of packet pairs to filter out samples distorted by cross-traffic.
Abstract: We present a new capacity estimation technique, called CapProbe. CapProbe combines delay as well as dispersion measurements of packet pairs to filter out samples distorted by cross-traffic. CapProbe algorithms include convergence tests and convergence speed-up techniques by varying probing parameters. Our study of CapProbe includes a probability analysis to determine the time it takes CapProbe to converge on the average. Through simulations and measurements, we found CapProbe to be quick and accurate across a wide range of traffic scenarios. We also compared CapProbe with two previous well-known techniques, pathchar and pathrate. We found CapProbe to be much more accurate than pathchar and similar in accuracy to pathrate, while providing faster estimation than both. Another advantage of CapProbe is its lower computation cost, since no statistical post processing of probing data is required.

Patent
23 Apr 2004
TL;DR: In this paper, the authors describe a method for supporting and using multiple communications channels corresponding to different transmit technologies and/or access technologies in parallel within a cell of a wireless communications system.
Abstract: Methods and apparatus for supporting and using multiple communications channels corresponding to different transmit technologies and/or access technologies in parallel within a cell of a wireless communications system are described. Mobile nodes support multiple technologies and can switch between the technology being used at a particular point in time, e.g., from a first channel corresponding to a first technology to a second channel corresponding to a different technology which provides better transmission characteristics, e.g., a better perceived channel quality. Mobiles maintain at least two sets of channel quality information at any one point in time. Mobiles select the better channel and communicate the channel selection to the base station or communicate channel quality information for multiple channels to the base station and allow the base station to select the channel corresponding to the technology providing the better conditions for the mobile. Different mobiles in the same cell may support different technologies.

Patent
Rajiv Laroia1, Junyi Li1, Sundeep Rangan1, Murari Srinivasan1, Frank A. Lane1, Prashanth Hande1 
15 Oct 2004
TL;DR: In this article, a single transmitter chain within a wireless terminal is coupled over time to a plurality of transmit antennas, where the switching decisions are based upon predetermined information, dwell information, and/or channel condition feedback information.
Abstract: Transmit and/or receive diversity is achieved using multiple antennas. In some embodiments, a single transmitter chain within a wireless terminal is coupled over time to a plurality of transmit antennas. At any given time, a controllable switching module couples the single transmitter chain to one the plurality of transmit antennas. Over time, the switching module couples the output signals from the single transmitter chain to different transmit antennas. Switching decisions are based upon predetermined information, dwell information, and/or channel condition feedback information. Switching is performed on some dwell and/or channel estimation boundaries. In some OFDM embodiments, each of multiple transmitter chains is coupled respectively to a different transmit antenna. Information to be transmitted is mapped to a plurality of tones. Different subsets of tones are formed for and transmitted through different transmit chain/antenna sets simultaneously. The balance of tones allocated to the subsets for each antenna are changed as a function of predetermined information, dwell information, and/or channel condition feedback information.

Patent
27 Sep 2004
TL;DR: In this article, the first data symbol stream is processed in accordance with a first spatial processing scheme (e.g., a transmit diversity or a spatial multiplexing scheme) to obtain a first set of symbol substreams.
Abstract: Techniques are provided for performing hierarchical coding in a multi-antenna communication system (e.g., a SIMO, MISO, or MIMO system). At a transmitter, a base stream and an enhancement stream are coded and modulated separately to obtain first and second data symbol streams, respectively. The first data symbol stream is processed in accordance with a first spatial processing scheme (e.g., a transmit diversity or a spatial multiplexing scheme) to obtain a first set of symbol substreams. The second data symbol stream is processed in accordance with a second spatial processing scheme (e.g., transmit diversity or spatial multiplexing) to obtain a second set of symbol substreams. The first set of symbol substreams is combined (e.g., using time division multiplexing or superposition) with the second set of symbol substreams to obtain multiple transmit symbol streams for transmission from multiple transmit antennas. A receiver performs complementary processing to recover the base stream and enhancement stream.

Patent
Hsiung-Kuang Tsai1
24 Mar 2004
TL;DR: In this paper, an optical interference display panel is disclosed that has a substrate, an OI reflection structure, and an opaque protection structure, which is adhered and fixed onto the substrate with an adhesive and encloses the optical interference reflection structure between the substrate and the OI protection structure.
Abstract: An optical interference display panel is disclosed that has a substrate, an optical interference reflection structure, and an opaque protection structure. The optical interference reflection structure has many color-changeable pixels and is formed on the substrate. The opaque protection structure is adhered and fixed onto the substrate with an adhesive and encloses the optical interference reflection structure between the substrate and the opaque protection structure. The opaque protection structure blocks and/or absorbs light, and light is thus not emitted outward by passing through defects in the optical interference reflection structure. Moreover, the opaque protection structure and the adhesive also prevent the optical interference reflection structure from being damaged by an external environment.

Patent
04 Nov 2004
TL;DR: In this article, MIMO systems and methods are provided to allow legacy devices to decode the length of a packet and to restrain from transmitting during that period, which is called stomping.
Abstract: A multiple-input multiple-output (MIMO) system can transmit on multiple antennas simultaneously and receive on multiple antennas simultaneously. Unfortunately, because a legacy 802.11a/g device is not able to decode multiple data streams, such a legacy device may “stomp” on a MIMO packet by transmitting before the transmission of the MIMO packet is complete. Therefore, MIMO systems and methods are provided herein to allow legacy devices to decode the length of a MIMO packet and to restrain from transmitting during that period. These MIMO systems and methods are optimized for efficient transmission of MIMO packets.

Patent
18 Feb 2004
TL;DR: In this article, a traffic to pilot ratio (T/P) is used to allocate a portion of the shared resource, allowing a mobile station flexibility in selecting its transmission format based on T/P.
Abstract: Techniques for efficient signaling to and from a plurality of mobile stations are disclosed. In one embodiment, a subset of mobile stations may be allocated a portion of the shared resource with one or more individual access grants, another subset may be allocated a portion of the shared resource with a single common grant, and yet another subset may be allowed to use a portion of the shared resource without any grant. In another embodiment, an acknowledge and continue command is used to extend all or a subset of the previous grants without the need for additional requests and grants, and their associated overhead. In one embodiment, a traffic to pilot ratio (T/P) is used to allocate a portion of the shared resource, allowing a mobile station flexibility in selecting its transmission format based on T/P.

Patent
02 Apr 2004
TL;DR: In this paper, a protection layer covers the cavity-side surface of a bottom electrode of a interferometric modulation pixel, and a sacrificial layer between the bottom electrode and the top electrode is being etched.
Abstract: A protection layer covers the cavity-side surface of a bottom electrode of a interferometric modulation pixel. Consequently, the protective layer protects the surface of the bottom electrode while a sacrificial layer between the bottom electrode and the top electrode is being etched. Thus, the distance between the bottom electrode and the top electrode is maintained, thereby ensuring that only the light with desired wavelengths is reflected by the interferometric modulation pixel.

Journal ArticleDOI
TL;DR: This paper introduces bidirectional motion compensated temporal filtering with unconnected pixel detection and I blocks and incorporates a recently suggested lifting implementation of the subband/wavelet filter for improved MV accuracy in an MC-EZBC coder.
Abstract: In conventional motion-compensated three-dimensional subband/wavelet coding, where the motion compensation is unidirectional, incorrect classification of connected and unconnected pixels caused by incorrect motion vectors (MVs) has resulted in some coding inefficiency and visual artifacts in the embedded low-frame-rate video. In this paper, we introduce bidirectional motion compensated temporal filtering with unconnected pixel detection and I blocks. We also incorporate a recently suggested lifting implementation of the subband/wavelet filter for improved MV accuracy in an MC-EZBC coder. Simulation results compare PSNR performance of this new version of MC-EZBC versus H.26L under the constraint of equal groups of pictures size, and show a general parity with this state-of-the-art nonscalable coder on several test clips.

Patent
08 Jan 2004
TL;DR: In this article, an optical-interference type display panel and a method for making the same are disclosed, wherein the display panel has a substrate on which multiple first conductive optical film stacks, supporting layers and multiple second conductive film stacks are formed.
Abstract: An optical-interference type display panel and a method for making the same are disclosed, wherein the display panel has a substrate on which multiple first conductive optical film stacks, supporting layers and multiple second conductive optical film stacks are formed. The substrate further has a plurality of connecting pads consisting of a transparent conductive film of the first conductive optical film stacks. Since the transparent conductive film is made of indium tin oxide, these connecting pads have the excellent anti-oxidation ability at their surface.

Patent
Wen-Jian Lin1
30 Sep 2004
TL;DR: In this article, an optical interference color display comprising a transparent substrate, an inner-front optical diffusion layer, a plurality of first electrodes, a patterned support layer, an optical film and a second electrodes is provided.
Abstract: An optical interference color display comprising a transparent substrate, an inner-front optical diffusion layer, a plurality of first electrodes, a patterned support layer, a plurality of optical films and a plurality of second electrodes is provided. The inner-front optical diffusion layer is on the transparent substrate and the first electrodes are on the inner-front optical diffusion layer. The patterned support layer is on the inner-front optical diffusion layer between the first electrodes. The optical film is on the first electrodes and the second electrodes are positioned over the respective first electrodes. The second electrodes are supported through the patterned support layer. Furthermore, there is an air gap between the second electrodes and their respective first electrodes.

Patent
10 Nov 2004
TL;DR: In this paper, the access network selects a multiple access transmission mode from a plurality of MAF transmission modes, and broadcasts the selected MAF to the access terminals, and the selected mode may include a mode in which data is code-division-multiplexed during the first portion of the time interval, and data is either time-division multiplexed or orthogonal-frequency division multiplexing during the second portion of time interval.
Abstract: A communication system includes a plurality of access terminals, and an access network. The access network schedules a transmission of data in a time interval from one of the access terminals. The access network selects a multiple access transmission mode from a plurality of multiple access transmission modes, and broadcasts the selected multiple access transmission mode to the access terminals. The selected mode may include a mode in which data is code-division-multiplexed during the time interval, and modes in which data is code-division-multiplexed during a first portion of the time interval, and data is either time-division-multiplexed or orthogonal-frequency-division-multiplexed during a second portion of the time interval.

Patent
Thomas Wrappe1
02 Apr 2004
TL;DR: In this article, microcell beacons are used to broadcast location information and identification information to improve the precision of position solutions in a wide area position determination system (e.g., a GPS system, an AFLT system, or a hybrid system).
Abstract: Methods and apparatuses for microcell beacon assisted position determination. In one embodiment, microcell beacons that are based on low cost, mass market electronics for wireless local area data communication (e.g., Bluetooth or WiFi) are used to broadcast to mobile stations location information and/or identification information, which can be used to look up for the location information, to improve the precision of position solutions in a wide area position determination system (e.g., a GPS system, an AFLT system, or a hybrid system). In one embodiment, the location information and/or the identification information are site specific; and, the distribution and the transmission strength of the microcell beacons are adjusted to prevent misidentification. In one embodiment, the microcell beacons have the transmission capability but not the receiving capability for wireless local area data communication; and, the mobile station has the receiving capability but not the transmission capability for wireless local area data communication.

Journal ArticleDOI
TL;DR: The article describes the air interface design adopted by 3GPP2, and presents simulation results that predict the performance of the high-speed broadcast system.
Abstract: The Third Generation Partnership Project 2 recently baselined the specification for a cdma2000/sup /spl reg// high-rate broadcast packet data air interface ("cdma2000 High Rate Broadcast-Multicast Packet Data Air Interface Specification", 3GPP2 C.50054). The standard allows high-speed delivery of packet data to multiple access terminals. The article describes the air interface design adopted by 3GPP2, and presents simulation results that predict the performance of the high-speed broadcast system.

Patent
07 May 2004
TL;DR: In this paper, the authors provide techniques to support fast frequency hopping with a code division multiplexed (CDM) pilot in a multi-carrier communication system (e.g., an OFDMA system).
Abstract: Techniques are provided to support fast frequency hopping with a code division multiplexed (CDM) pilot in a multi-carrier communication system (e.g., an OFDMA system). Each transmitter (e.g., each terminal) in the system transmits a wideband pilot on all subbands to allow a receiver (e.g., a base station) to estimate the entire channel response at the same time. The wideband pilot for each transmitter may be generated using direct sequence spread spectrum processing and based on a pseudo-random number (PN) code assigned to that transmitter. This allows the receiver to individually identify and recover multiple wideband pilots transmitted concurrently by multiple transmitters. For a time division multiplexed (TDM)/CDM pilot transmission scheme, each transmitter transmits the wideband pilot in bursts. For a continuous CDM pilot transmission scheme, each transmitter continuously transmits the wideband pilot, albeit at a low transmit power level. Any frequency hopping rate may be supported without impacting pilot overhead.

Patent
12 Nov 2004
TL;DR: In this article, an uplink channel response matrix is obtained for each terminal and decomposed to obtain a steering vector used by the terminal to transmit on the uplink, which is then used to determine the best set of terminals for uplink transmission.
Abstract: An uplink channel response matrix is obtained for each terminal and decomposed to obtain a steering vector used by the terminal to transmit on the uplink. An “effective” uplink channel response vector is formed for each terminal based on its steering vector and its channel response matrix. Multiple sets of terminals are evaluated based on their effective channel response vectors to determine the best set (e.g., with highest overall throughput) for uplink transmission. Each selected terminal performs spatial processing on its data symbol stream with its steering vector and transmits its spatially processed data symbol stream to an access point. The multiple selected terminals simultaneously transmit their data symbol streams via their respective MIMO channels to the access point. The access point performs receiver spatial processing on its received symbol streams in accordance with a receiver spatial processing technique to recover the data symbol streams transmitted by the selected terminals.

Patent
15 Nov 2004
TL;DR: In this paper, a control channel used for transmitting control information is partitioned into a plurality of sub-channels each of which is operated at a specific data rate, and one of the subchannels is selected based on one or more selection criteria for transmission control information from an access point to the respective user terminal.
Abstract: According to one aspect of the invention, a method is provided in which a control channel used for transmitting control information is partitioned into a plurality of subchannels each of which is operated at a specific data rate. For each of one or more user terminals, one of the subchannels is selected based on one or more selection criteria for transmitting control information from an access point to the respective user terminal. Control information is transmitted from the access point to a user terminal on a particular subchannel selected for the respective user terminal. At the user terminal, one or more subchannels are decoded to obtain control information designated for the user terminal.

Patent
14 Oct 2004
TL;DR: In this article, a mobile communications device initiates a handoff from its current base station (BS) sector network attachment point to a new BS sector, e.g., via a network link.
Abstract: A mobile communications device initiates a handoff from its current base station (BS) sector network attachment point to a new BS sector. The mobile sends a handoff request over its current wireless link to the current BS sector, which forwards the request to the new BS sector, e.g., via a network link. The new BS sector processes the request assigning dedicated resources, e.g., an identifier and dedicated uplink segments. Information identifying the allocated resources is conveyed from the new BS sector via the current BS sector to the mobile. The mobile determines the time of the allocated dedicated segments based upon a received beacon signal from the new BS sector with known timing relationships to dedicated segments. The mobile breaks the original wireless link just prior to the time of the first assigned dedicated segment. The mobile communicates information on the assigned dedicated segments to perform registration operations, e.g., timing synchronization and power control, establishing a new wireless link.