Abstract: A frame structure that is ordinarily optimized for providing variable high data rates also includes the flexibility to efficiently carry lower data rate, lower latency frames using sub-framing. Superframes, each comprised of a predetermined number of frames, carry voice and data communications at one or more variable data rates. The size of a superframe is limited, such as by the delay tolerance for voice transmission, typically 20 ms. Each voice customer is allotted one or more frames or portions of frames within the superframe, called sub-frames, as is needed to deliver the lower data rate, low latency voice communication. The allocation for the voice customers is not fixed, but varies as the data rate varies over time. Any bits in a frame that are not needed to carry voice communication are assigned to carry data having compatible data rate requirements. Additionally, the sub-framing concept may be extended to include ATM cells.

Abstract: In an apparatus and method for performing secure messaging in a digital communications network, a module sends a registration message including an initial challenge and an identification of itself to the server. In response, the server sends a message, including a response to the module's challenge and a challenge to the module from the server, to the module based on the value and service of the initial challenge. The module uses the validity of the server's response to determine whether a transmitted message is authentic. A valid response corresponds to an authentic message. Alternatively, a server may initiate communications with a module. Once the initial communication is established, messaging typically continues for all transactions between the server and the module for one or more classes of transactions. The authentication process is repeated for each message.

Abstract: A digital performance monitoring method and system for an optical communications system utilizes a channel monitor and a digital signal processor (DSP). The channel monitor is designed to monitor a respective channel signal of the optical communications system, and includes: a sample memory adapted to store sample data including a set of sequential N-bit (where N≧1) samples generated by an Analog-to-Digital (A/D) converter at a timing of a predetermined sample clock during a predetermined time interval; and a controller adapted to control storage of the sample data to the sample memory. The digital signal processor (DSP) is designed to calculate at least one performance parameter of the optical communications system based on the sample data.

Abstract: Nonlinearity-induced signal distortions are compensated by processing an input communications signal, in the electrical domain prior to Electrical-to-optical conversion and transmission through an optical link of a communications system. According to the invention, a compensation operator is determined that substantially mitigates the nonlinearity-induced signal distortions imparted to an optical signal traversing the communications system. The input communications signal is then input to the compensation operator to generate a predistorted electrical signal. This predistorted electrical signal is then used to modulate an optical source to generate a corresponding predistorted optical signal for transmission through the optical communications system. With this arrangement, arbitrary nonlinearity-induced signal distortions imparted by the optical link can be compensated in such a manner that a comparatively undistorted optical signal is obtained at the receiving end of the optical link.

Abstract: Polarization Dependent Effects (PDEs), including Polarization Mode Dispersion (PMD) and Polarization Dependent Loss (PDL) imposed on optical signals conveyed through an optical link are compensated by processing an input signal in the electrical domain prior to transmission. A compensation function is derived that at least partially compensates the PDEs. The communications signal is then processed in the electrical domain using the compensation function to generate an electrical predistorted signal. The electrical predistorted signal is then used to modulate an optical source to generate a corresponding predistorted optical signal for transmission through the optical link. The PDEs of the optical link operate of the predistorted optical signal such at that substantially undistorted optical signal is received at a receiving end of the link.

Abstract: Optical dispersion imposed on a communications signal conveyed through an optical communications system is compensated by modulating the communications signal in the electrical domain. A compensation function is determined that substantially mitigates the chromatic dispersion. The communications signal is then modulated in the electrical domain using the compensation function. Electrical domain compensation can be implemented in either the transmitter or the receiver end of the communications system. In preferred embodiments, compensation is implemented in the transmitter, using a look-up-table and digital-to-analog converter to generate an electrical predistorted signal. The electrical predistorted signal is then used to modulate an optical source to generate a corresponding predistorted optical signal for transmission through the optical communications system.

Abstract: An improved method and transceiver for using the method for detecting header errors includes a header processor for reconfiguring an ATM cell header by extracting the 8 bit header error check (HEC) and replacing it with an enhanced 16 or 24 bit HEC (EHEC). On the receive path, the received header is compared to the EHEC and if errors are indicated, the cell is discarded. Enhancements include FEC encoding on the entire cell during transmission, and if during reception uncorrectable errors exist using said EHEC to determine whether the error is in the header or is in the payload. If a cell with an error in its payload belongs to a group of related cells, for example an AAL5 frame, the system discontinues the transmission of the remaining cells of the frame.

Abstract: An improved method and transceiver for using the method for detecting header errors includes a header processor for reconfiguring an ATM cell header by extracting the 8 bit header error check (HEC) and replacing it with an enhanced 16 or 24 bit HEC (EHEC). On the receive path, the received header is compared to the EHEC and if errors are indicated, the cell is discarded. Enhancements include FEC encoding on the entire cell during transmission, and if during reception uncorrectable errors exist using said EHEC to determine whether the error is in the header or is in the payload. If a cell with an error in its payload belongs to a group of related cells, for example an AAL5 frame, the system discontinues the transmission of the remaining cells of the frame.

Abstract: The invention relates to systems and methods for receiving signals modulated with a carrier frequency, wherein the signals include spreading chip sequences having at least one zero. The invention includes a method of receiving and despreading spread spectrum signals wherein the spread spectrum signals include spreading chip sequences having at least one zero and at least one non-zero chip. The method includes receiving and sampling a spread spectrum communication signal. The receiver generates a despreading code which is synchronized with the sampled spread spectrum communication signal. The sampled spread spectrum communication signal is then despread with the despreading code by omitting at least one operation involving at least one zero chip. The invention further includes a receiver configured to receive signals modulated with a carrier frequency over a channel, wherein the signals include spreading chip sequences having at least one zero.

Abstract: An optical network system having a global controller capable of controlling all the elements of the network. The controller receives performance data from each optical network element and calculates a performance value for each channel transmitting through the system. The controller then isolates the channel with the minimum performance value and tests possible changes in network element parameters to find a change which would increase this performance value. Once such a change is found, it is implemented and the system is reoptimized.

Abstract: This invention provides a conferencing arrangement for use with two or more wireless terminals. According to the invention, the conferencing arrangement receives signals from a plurality of input communication paths of which at least two are from wireless terminals. In one embodiment of the invention, the wireless terminals will receive either a low bit rate (LBR) signal which has undergone conversion from a pulse code modulated (PCM) signal, or an LBR signal forwarded from an input terminal without any conversion. Advantageously, the ability to forward an original LBR signal from a wireless terminal to one or more output terminals reduces unnecessary tandem encoding. In another embodiment, only LBR signals required for conference summing are decoded and encoded, thereby resulting in hardware savings.

Abstract: An adaptable orthogonal frequency-division multiplexing system (OFDM) that uses a multiple input multiple output (MIMO) to having OFDM signals transmitted either in accordance with time diversity to reducing signal fading or in accordance with spatial diversity to increase the data rate. Sub-carriers are classified for spatial diversity transmission or for time diversity transmission based on the result of a comparison between threshold values and at least one of three criteria. The criteria includes a calculation of a smallest eigen value of a frequency channel response matrix and a smallest element of a diagonal of the matrix and a ratio of the largest and smallest eigen values of the matrix.

Abstract: This invention proposes a novel common packet data channel (CPDC) system structure and method to efficiently provide variable-rate packet data services in CDMA system. This system uses common code channels to serve packet data calls for a plurality of packet data users within a cell or sector. On the forward link (base station-to-mobile), an ATM-type multiplexing scheme is employed on a common code channel, while a spread ALOHA-type random access scheme is used on the reverse link (mobile-to-base station). The overhead due to call setup and channel assignment in a conventional circuit-switched system is not required in this system. The delay due to the call setup is reduced. In addition, ATM cells can be directly transmitted over the air interface. Novel transceiver architectures for the terminal and base station for implementing a system as well as particular channel signal structures are disclosed.

Abstract: Methods and apparatus are disclosed for improving performance of handoff in a telecommunications system having a plurality of base stations and a mobile unit in handoff communication (uplink only or in both uplink and downlink) with at least two of the base stations over at least first and second respective communications links. The first and second communications links each comprise at least one base station transceiver subsystem (BTS), at least one radio connection controller (RCC), at least one mobile switching center (MSC), and at least one transcoder or data server. The RCC checks whether a given information frame from any of the BTSs is valid. If one or more information frames is valid, then the RCC forwards a valid frame to the transcoder or a data server. If none of the received frames is valid, the RCC then decodes a R=1/n code constructed from data received from the BTSs and checks whether the decoded information frame is valid using a checksum or CRC transmitted with the information frame.

Abstract: An apparatus for transmitting software to a subscriber device in a communication network, which includes a processor, a database coupled to the processor, and a communication device for providing software to a subscriber device. The database contains information about subscribers of a communication network. A method for transmitting software to subscriber devices in a communication network, comprising identifying a subscriber device which requires a software update, transmitting a first signal from a processor to the subscriber device, initiating a communication channel between the subscriber device and the processor, and transmitting a second signal to the subscriber device. The second signal contains software.

Abstract: A high layer protocol organizes Unidirectional Streaming Services (USS) data into frames and said data is transmitted to the wireless user's terminal. The USS data is not delivered until a criteria is satisfied, e.g., the receive buffer is filled to an appropriate value. After the USS data is received, the receiver verifies the received frames. If an error is detected a message is sent from the wireless terminal to the server (providing the unidirectional streaming service) requesting retransmission of the corrupted frame. This is a form of ARQ protocol. If the retransmitted frame arrives prior to the time that frame needs to be delivered, the corrupted frame is replaced by the retransmitted frame. Otherwise, if the retransmitted frame is not received prior to the time that frame needs to be delivered, the corrupted frame is reconstructed. Any retransmitted frame which arrives too late is discarded.

Abstract: Methods and apparatus for transmitting data over a multi-channel CDMA system are disclosed in accordance with the teachings of the present invention wherein the system includes an encoder for encoding a data stream with error correction, an interleaver for interleaving the data stream, a multiplexor for multiplexing a plurality of power control symbols onto the data stream, and an inverse-multiplexor for inverse-multiplexing the data stream onto multiple different communication channels. The system may also include additional error correction encoding and interleaving steps.

Abstract: Methods and apparatus for generating spreading codes in a CDMA system are disclosed in accordance with the teachings of the present invention wherein the system includes a pseudonoise (PN) code generator and a logic device configured to replace a portion of a PN code generated by the PN code generator with at least one zero or to add at least one zero to a PN code generated by the PN code generator. The PN code generator generates a PN code made up of chips. One or more of these chips may be replaced by zeros or one or more zeros may be inserted between chips. Thus, when combined at a chip level with a substantially orthogonal code such as a Walsh code the resulting spreading code will be less effected and in some instances not effected at all by certain time delays inserted into the system (i.e time lag from multi-path dispersive transmissions).

Abstract: Aspects of global positioning system (GPS) technology and cellular technology are combined in order to provide an effective and efficient position location system. In a first aspect of the invention, a cellular network is utilized to collect differential GPS error correction data, which is forwarded to a mobile terminal over the cellular network. The mobile terminal receives this data, along with GPS pseudoranges using a GPS receiver, and calculates its position using this information. According to a second aspect, when the requisite number of GPS satellites are not in view of the mobile terminal, then a GPS pseudosatellite signal, broadcast from a base station of the cellular network, is received by the mobile terminal and processed as a substitute for the missing GPS satellite signal.

Abstract: The time of arrival of a global positioning system signal and the time of arrival of a code division multiple access pilot signal, from a base station, are estimated at a mobile radiotelephone. Both estimates are performed relative to a local clock in the radiotelephone. These signals are calibrated for the time delay produced by the transmitter at the base station and the time delay produced by the receiver in the radiotelephone.