Abstract: A “unified” modulator for multiple modulation schemes (e.g., GMSK and 8PSK) is described. The waveform for each modulation scheme is generated based on a set of one or more pulse shaping functions. The waveforms for all supported modulation schemes may be generated based on a composite set of all the different pulse shaping functions. The unified modulator includes a filter for each pulse shaping function in the composite set. To generate the waveform for a selected modulation scheme, the set of one or more filters for this modulation scheme is enabled and all other filters are disabled. The outputs from all enabled filters are summed to generate a modulator output. When switching between modulation schemes, a smooth transition may be obtained by (1) providing a suitable data pattern for each filter to be enabled or disabled and (2) generating symbols for the new modulation scheme with an appropriate initial phase.

Abstract: Wireless terminals, e.g., mobile nodes, receive, identify, and measure broadcast signals from a plurality of cells. They determine relative transmission power relationships corresponding to the received measured signals and determine at least two channel gain ratios. A geographic area is determined corresponding to the obtained at least two channel gain ratios and information indicating the geographic region in which such gain ratios may be detected. Each cell's base station transmits broadcast signals, e.g., beacon signals, pilot signals, and/or assignment signals for one more carriers. Some base stations use multiple carriers at different power levels. Some adjacent cells use different power levels for the same carrier. This carrier diversity approach tends to reduce overall interference in the system, yet provides mobiles with a variety of different strength signals which may be monitored and which vary as a function of distance from the source transmitter.

Abstract: Systems and methods are provided in which an origination station broadcasts a broadcast program to at least one of a plurality of destination stations. A first destination station (or a first group of destination stations) receives a first registration period parameter from the origination station. The first registration period parameter specifies a first period during which the first destination station must register with the origination station. The first destination station may block any attempted registration request that occurs outside the first period. Alternatively, the origination station can deny any attempted registration request by the first destination station that occurs outside the first period. If the registration request from the first destination station is sent before the first period begins, then the destination station can periodically request registration until a request is sent within the first period.

Abstract: Techniques for recovering a desired transmission in the presence of interfering transmissions are described. For iterative detection and cancellation, multiple groups of code channels are formed for a plurality of code channels for at least one sector. Processing is performed for the multiple groups of code channels in multiple iterations. For each iteration, data detection and signal cancellation are performed for the multiple groups of code channels in multiple stages, e.g., in a sequential order starting with the strongest group to the weakest group. Each stage of each iteration may perform data detection, signal reconstruction, and signal cancellation. Each stage of each iteration may also perform equalization, data detection, signal reconstruction, and signal cancellation.

Abstract: A terminal communicates with a first wireless network and obtains a list of cells in a second wireless network to measure. The terminal operates in a compressed mode and receives multiple transmission gap pattern sequences for different measurement purposes, e.g., RSSI measurements, BSIC identification, and BSIC re-confirmation. The terminal utilizes each transmission gap for its designated purpose or an alternate purpose. For each transmission gap, the designated purpose for the transmission gap is ascertained, and whether the transmission gap is usable for an alternate purpose is also determined based on at least one criterion. The transmission gap is used for the alternate purpose if the at least one criterion is satisfied and is used for the designated purpose otherwise. For example, a transmission gap designated for RSSI measurement may be used for BSIC identification, a transmission gap designed for BSIC identification or BSIC re-confirmation may be used for RSSI measurement, and so on.

Abstract: At a mobile device, a total received power represents signals received from all access points. In order to calculate an appropriate transmit power for communication with a single access point, a mobile device determines a per sector received power level. The mobile device can ascertain a time-domain channel response from each access point pilot signal, ascertain a received digital power lever per sector from each access point pilot signal and, based in part on the digital power level, calculate a received power level from each access point. A per sector received power level can be utilized to conserve battery power and/or to reduce interference in a wireless communications network.

Abstract: Apparatuses and methodologies are described that facilitate packet aware scheduling are provided. In some embodiments, if all of the information of a packet cannot be scheduled in a single transmission period, additional resources may be assigned to transmission of the contents of the packet based upon latency requirements and/or transmission constraints of the packet.

Abstract: A level shifter includes an inverting circuit, a cross-coupled level shifting latch, and a SR logic gate latch. The first and second outputs of the level shifting latch are coupled to the set (S) and reset (R) inputs of the SR latch. The inverting circuit, that is powered by a first supply voltage VDDL, supplies a noninverted version of an input signal onto a first input of the level shifting latch and supplies an inverted version of the input signal onto a second input of the level shifting latch. A low-to-high transition of the input signal resets the SR latch, whereas a high-to-low transition sets the SR latch. Duty cycle distortion skew of the level shifter is less than fifty picoseconds over voltage, process and temperature corners, and the level shifter has a supply voltage margin of more than one quarter of a nominal value of VDDL.

Abstract: Techniques for performing equalization at a receiver are described. In an aspect, equalization is performed by sub-sampling an over-sampled input signal to obtain multiple sub-sampled signals. An over-sampled channel impulse response estimate is derived and sub-sampled to obtain multiple sub-sampled channel impulse response estimates. At least one set of equalizer coefficients is derived based on at least one sub-sampled channel impulse response estimate. At least one sub-sampled signal is filtered with the at least one set of equalizer coefficients to obtain at least one output signal. One sub-sampled signal (e.g., with largest energy) may be selected and equalized based on a set of equalizer coefficients derived from an associated sub-sampled channel impulse response estimate. Alternatively, the multiple sub-sampled signals may be equalized based on multiple sets of equalizer coefficients, which may be derived separately or jointly.

Abstract: Techniques for generating quality indicator bits in a wireless communication system (e.g., a cdma2000 that implements IS-2000). In one method, a determination is first made whether a good data frame was received from a first transmission for the current frame interval. This first transmission may be a non-continuous transmission on a forward dedicated control channel (F-DCCH) defined by IS-2000. If a good data frame was received, then a quality indicator bit is generated based on the good data frame. Otherwise, the quality indicator bit is generated based on a second transmission, which may comprise power control bits that are transmitted even when no data frames are sent in the first transmission. The received signal quality for the power control bits can be measured and compared against a threshold, and the quality indicator bit is then set based on the result of the comparison. The threshold may be dynamically updated.

Abstract: A system and method for providing a secure environment for mobile telephones and other devices are disclosed. The system and method may utilize trust zoning, layered memory, and a secure matrix model having, for example, a memory protection module for protecting memory; a secure debug module for ensuring security of the debug module; a secure file system module for protecting the secure file system; and a trusted time source module for protecting components. Embodiments of the present invention may protect against security attacks on a variety of hardware and software components while permitting suitable levels of accessibility for developmental and maintenance purposes.

Abstract: A differential amplifier, which has good linearity and noise performance, includes a first side that includes first, second, third, and fourth transistors and an inductor. The first and second transistors are coupled as a first cascode pair, and the third and fourth transistors are coupled as a second cascode pair. The third transistor has its gate coupled to the source of the second transistor, and the fourth transistor has its drain coupled to the drain of the second transistor. The first transistor provides signal amplification. The second transistor provides load isolation and generates an intermediate signal for the third transistor. The third transistor generates distortion components used to cancel third order distortion component generated by the first transistor. The inductor provides source degeneration for the first transistor and improves distortion cancellation. The sizes of the second and third transistors are selected to reduce gain loss and achieve good linearity for the amplifier.

Abstract: Techniques for performing interference cancellation in a wireless (e.g., CDMA) communication system are described. For a single-sector interference canceller, received samples are processed (e.g., despread) to isolate a signal from a transmitter (e.g., a base station) and obtain input samples. The input samples are transformed based on a first transform (e.g., a fast Hadamard transform) to obtain received symbols for multiple orthogonal channels (e.g., Walsh bins). The received symbols for the multiple orthogonal channels are scaled with multiple gains to obtain scaled symbols. The gains may be related to the inverses of the power estimates for the orthogonal channels. The scaled symbols are transformed based on a second transform (e.g., an inverse fast Hadamard transform) to obtain output samples, which are processed (e.g., spread) to obtain interference-canceled samples having the signal from the transmitter suppressed.

Abstract: A wireless data network delivers packets from a network router to a mobile station so that each application running on the mobile station receives an adequate quality of service (QoS). The mobile station sends configuration messages to the network router containing prioritized filters associated with each application. The router filters incoming IP packets into IP flows having the appropriate QoS for the corresponding application. The configuration messages consume valuable air interface resources. Network resources are conserved by assigning precedence values to filters in such a way that fewer configuration messages are needed to reorder the filters when new filters are added. Precedence values for existing filters are spread out in one portion of the precedence space. When the precedence values in that portion are insufficient to accommodate new filters with the correct priority, both new and existing filters are reassigned precedence values in an unassigned portion of the precedence space.

Abstract: Techniques for operating two receivers to receive data and paging from two systems are described. A primary receiver is associated with better performance than a secondary receiver under poor RF conditions. The two receivers may be operated in either a hybrid mode in which the primary receiver is used to receive paging or a simultaneous mode in which the second receiver is used to receive paging. One of the modes may be selected for use based on RF conditions, received power, demodulation metrics, and/or other criteria. In one design, a mode is selected based on the received power and one or more thresholds. In another design, the hybrid mode is selected for poor RF conditions and, for good RF conditions, the hybrid or simultaneous mode is selected based on received power.

Abstract: A wireless communication device (WCD) performs DC removal on a received signal using a coarse DC removal unit that removes relatively large DC components and a fine DC removal loop that removes residual DC components. The coarse DC removal unit can be implemented in a receiver, and the fine DC removal loop can be implemented in a modem. In addition, a coarse DC estimation loop implemented on the modem may be coupled to the coarse DC removal unit to update DC offset values stored in the DC removal unit. By storing coarse DC offset values locally on the receiver, DC removal can be achieved very quickly.

Abstract: Techniques to efficiently attempt acquisition of a packet data system (e.g., an IS-856 system). If a terminal has acquired one or more channels in a voice/data system (e.g., an IS-2000 system), then it can attempt acquisition on channels in the packet data system that are co-located with the acquired channels in the voice/data system. Multiple acquisition modes may be used, and on-going acquisition attempts on the co-located channels may be performed using one acquisition mode at a time in order to reduce power consumption. Acquisition attempts may be performed in a “ping-pong” manner to improve the likelihood of acquisition. For a ping-pong search, an acquisition attempt is made on the most recently acquired channel prior to an acquisition attempt on each of the remaining channels. Received signal strength estimates may also be obtained for selected channels and may be used to determine whether or not to attempt acquisition on these channels.

Abstract: Searcher hardware is multiplexed to perform simultaneous searches in either an IS-95 CDMA mode or a GPS mode. In the IS-95 mode, the search hardware is time-multiplexed into a number of searcher time slices, each of which can generate a PN sequence to despread a data sequence. In the GPS mode, the search hardware is configured as a number of distinct GPS channels, each of which can generate a Gold code sequence for tracking a GPS signal from a particular GPS satellite. This configuration allows the searcher to perform multiple GPS signal searches simultaneously. Signal searching in both IS-95 and GPS modes is performed at significantly higher speeds compared to conventional searcher hardware. Moreover, the search hardware can be dynamically configured to operate in either the IS-95 or the GPS mode, eliminating the need for dedicated circuitry for each mode of operation.

Abstract: An HDLC accelerator includes a deframer and framer to respectively accelerate the deframing and framing processes for PPP packets. The deframer includes an input interface unit, a detection unit, a conversion unit, and an output interface unit. The input interface unit receives a packet of data to be deframed. The detection unit evaluates each data byte to detect for special bytes (e.g., flag, escape, and invalid bytes). The conversion unit deframes the received data by removing flag and escape bytes, “un-escaping” the data byte following each escape byte, providing a header word for each flag byte, and checking each deframed packet based on a frame check sequence (FCS) value associated with the packet. The output interface unit provides deframed data and may further perform byte alignment in providing the deframed data. A state control unit provides control signals indicative of specific tasks to be performed for deframing.

Abstract: An RF output power amplifier (PA) of a cellular telephone includes first and second Class AB amplifier circuits. If the cellular telephone is to operate in a high power operating mode, then the first amplifier drives the PA output terminal. The power transistor(s) in the first amplifier is/are biased at a first DC current and a first DC voltage so as to optimize efficiency and linearity at high output powers. If the cellular telephone is to operate in a low power operating mode, then the second amplifier drives the output terminal. The power transistor(s) in the second amplifier is/are biased at a second DC current and a second DC voltage so as to optimize efficiency and linearity at low output powers. By sizing the power transistors in the amplifiers appropriately, emitter current densities are maintained substantially equal so that PA power gain is the same in the two operating modes.