Techniques to implement MBMS services in a wireless communication system. In one aspect, a method is provided for processing data for transmission to a plurality of terminals. Frames of information bits (which may have variable rates) are provided to a buffer implementing a matrix. The matrix is padded with padding bits based on a particular padding scheme to support variable frame rates. The frames are then coded based on a particular block code to provide parity bits. The frame of information bits and the parity bits are then transmitted to the terminals. In another aspect, a method is provided for controlling the transmit power of a data transmission to a plurality of terminals. In accordance with the method, TPC streams are received from the terminals and processed to obtain a stream of joint power control commands used to adjust the transmit power of the data transmission.

Multi-media broadcast and multicast service (MBMS) in a wireless communication system

Method for transferring information between a vehicle and a transmitter in which a unique pseudorandom noise signal is transmitted by the transmitter in a carrier-less fashion composed of frequencies within a pre-selected band. Information is encoded in the noise signal relating to an identification of the transmitter and a position of the transmitter and the vehicle is provided with a device for extracting the information from the noise signal. The code to use for encoding the noise signal may be selected based on the position of the transmitter so that analysis of the code, or a portion thereof, provides an indication of the position of the transmitter. Information about accidents, weather conditions, road conditions, map data and traffic control devices and about errors in a GPS signal can also be encoded in the noise signals. The transmitter may be at a fixed location or in another vehicle to thereby enable vehicle-to-vehicle communications for the purposes of collision avoidance, intelligent highway applications and the like.

Method and arrangement for communicating between vehicles

An uplink common physical channel (random access channel) frame structure is disclosed with a separate preamble and data portion. The preamble is used by a base station to detect that a mobile station is attempting a random access request. The data portion of the channel includes user data, and pilot symbols that provide energy for channel estimation during reception of the data portion. A guard interval (TG) is preferably inserted between the preamble and data portion of the frame, which enables data detection to occur during an idle period. As such, the frame structures for both the common physical (random access) uplink channel and dedicated physical (traffic) uplink channel are compatible.

Random access in a mobile telecommunications system

A process for reducing the amount of overhead data in ATM cell headers prior to transmission both upstream and downstream on an HFC cable plant or other transmission media using SCDMA on at least the upstream path, without loss of either IP or Ethernet addressing information. A virtual link between each remote unit and a central unit is established using multiplexing to establish a virtual link to every remote unit. Downstream ATM cells are optimized by stripping off all but 2 bytes to leave a 50 byte cell. Incoming IP packets have their IP addressing information used to look up Ethernet domain address information for the RU and destination process to which this RU is coupled. An Ethernet header is appended to each IP packet as is RFC 1483 bytes to signal the start of the packet. The packet is parsed into 48 byte ATM cell payloads. VPI/VCI information for the virtual link of the remote unit to which the packet is bound is looked up using the Ethernet address information. The last cell in the packet is indicated by encoding 9th bits. The CU cable data modem formatter then generates optimized downstream 2-byte headers for each downstream ATM cell by stripping off all but 2 bytes of VPI/VCI data. 9th bits are added to each byte, and these 9th bits are encoded with last cell, normal cell and idle cell information and start codes so that cell boundaries can be located.

Lower overhead method for data transmission using ATM and SCDMA over hybrid fiber coax cable plant

A subscriber unit for use in a multiple access spread-spectrum communication system includes a spread spectrum radio interface, responsive to a rate function signal from a base station, and first and second despreaders. The base station assigns the rate function spread-spectrum message channels and the first despreader recovers and modifies an information signal one of the spread spectrum message channels. The information channel mode is then modified for processing by the second despreader, with the second despreader supporting a different information signal rate. The subscriber unit has a capability of communicating with a dynamically changing a transmission rate of an information signal which includes multiple spread spectrum message channels. The system includes a closed loop power control system for maintaining a minimum system transmit power level for a radio carrier station and the subscriber units, and system capacity management for maintaining a maximum number of active subscriber units for improved system performance.

Code division multiple access (CDMA) communication system

A new signal processing architecture for base stations and gateways (124, 126) used in spread spectrum communication systems (100) that simplifies data transfer, reduces required bus capacity, and does not require special synchronization of signals that are to be combined. A series of transmission modules (5081-508M) are used to transfer data to corresponding ones of a series of analog transmitters (4121-412M) used to form communication circuits for each system user. Each transmission module (5081-508M) employs a series of encoders (502MR) and modulators (504MS) to form spread communication signals, using appropriate PN spreading codes. Spread spectrum communication signals from each module (508) for each system user (D), are summed together (5101-510M) and transferred to a single analog transmitter (412) associated with that module. The signals being combined are automatically synchronized by common timing signals used for elements within each module. The number of processing elements within each module is such that at least one processing path is available for each user or user channel over which it is desired to transmit information through the connected analog transmitter (4121-412M). Data is output from the modules (5081-508M) at a greatly reduced transfer rate which can be more easily accommodated using current technology. This is very useful for satellite based communication systems, or high capacity cellular systems, and this system architecture can be accomplished cost effectively using a series of easily manufactured circuit modules.

A multi-user communication system architecture with distributed transmitters

The invention provides a layered channel software element (200) which supervises the operation of channel element modem resources (59) in a CDMA cellular telephone system (8) that includes forward channels (20a, 22a) for conveying message and signalling data from a CDMA system base station (12) to mobile units (16, 18) and reverse channels (20b, 22b) for conveying message and signalling data from mobile units (16, 18) to base stations (12, 14). Each channel is implemented in a channel element (59) including a general purpose processor (60) and a modem application-specific integrated circuit ASIC (62). The layered channel software element (200) executes on the general processor (60). The layered channel software element (200) provides a structure and function for transferring message and signalling data between the telecommunication system (10) and the modem ASIC (62) via channel element controller (44), and also for establishing channel operations by providing channel configuration information to the modem ASIC (62).

Layered channel element in a base station modem for a cdma cellular communication system

A handoff technique in which system users detect transitions in service between a current service area (B10, S4) and an adjacent service area (B2, S5), and request a forward link channel in the new service area (B2, S5) when a detected signal strength for the new service area exceeds predetermined threshold levels. The forward communications link in the current service area is maintained until the strength of the new service area signal (B2, S5) reaches a certain level and appropriate channel quality is confirmed, as based on various known criteria. Typically, service area transitions are detected using the signal strength of pilot or paging signals associated with service areas, which are used to determine a relative signal strength of new service area signals. Pilot signal level adjustments used to counter roll-off effects are detected and compensated for in comparing signal levels. To minimize the burden on system resources, new service area signals are not selectable until a minimum time has passed, or a minimum change in energy from a prior pilot signal is detected. In addition, communications using the previous service area can be dropped almost immediately upon engaging the new service area.

Method and apparatus for adjacent service area handoff in communication systems

The present invention discloses a variable rate transmission system wherein a packet of variable rate data is modulated in accordance with a traffic channel sequence supplied by a traffic PN generator (63) if the capacity of said traffic channel is greater than or equal to said data rate of the packet. If the capacity of said traffic channel is less than said data rate, the packet of variable rate data is modulated in accordance with the traffic channel sequence supplied by the traffic PN generator (63) and in accordance with at least one overflow channel sequence supplied by an overflow channel generator (65). The present invention further discloses a receiving system for receiving variable rate data where a received packet of variable rate data is demodulated in accordance with a traffic channel sequence supplied by a traffic PN generator (104) if the capacity of said traffic channel is greater than or equal to a data rate of said packet. If the capacity of said traffic channel is less than said data rate of the packet of variable rate data, the received packet is demodulated in accordance with a traffic channel sequence supplied by a traffic PN generator (104) and in accordance with at least one overflow channel sequence supplied by an overflow channel generator (120).

Method and apparatus for providing variable rate data in a communications system using non-orthogonal overflow channels

The present invention is a system and method for increasing user capacity on a slotted random access channel in a spread spectrum communications system (100) by using a multi-part access probe (502). First and second parts (508, 510) of an access probe preamble (604) are modulated using a short PN code sequence (620), and the second part and remainder of the access probe (502) is modulated using a long PN code sequence. Information to be transmitted by the access probe (502) is modulated on the second part (606) of the access probe (502), and the access probe is transmitted so that the first part (508) of the probe preamble (604) falls within the boundaries of an access channel slot (402). In one embodiment, time slots (402) in access channels (400) used for access signal reception are made the length of the first part (508). In a further embodiment, time slots (402) in a plurality of adjacent access channels used for access signal reception may be longer than said first part (508) but are offset in time from each other by the length or period of the first part.

David S. Miller

Papers

A multi-user communication system architecture with distributed transmitters

Layered channel element in a base station modem for a cdma cellular communication system

Method and apparatus for adjacent service area handoff in communication systems

Method and apparatus for providing variable rate data in a communications system using non-orthogonal overflow channels

Access channel slot sharing