REVERSE LINK PILOT INTEGRATED WITH BLOCK CODES

A method and apparatus for encoding digital communication signals is described herein. A wireless communication unit may comprise a processor configured to produce first symbols derived from data bits and parity bits. The wireless communication unit may transmit a wireless signal including the first symbols and reference symbols in a time interval including a plurality of symbol time intervals. In one of the symbol time intervals a plurality of the reference symbols may be transmitted in a predetermined pattern, which may have the reference symbols not adjacent to each other. A base station may receive a wireless signal including first and reference symbols. In one of the symbol time intervals a plurality of the reference symbols may be received in a predetermined pattern. The base station may then demodulate the first symbols using the reference symbols, wherein the first symbols are derived from data bits and parity bits. 1. A wireless communication unit comprising:a processor configured to produce first symbols derived from data bits and parity bits; anda transmitter configured to transmit a wireless signal including the first symbols and reference symbols in a time interval including a plurality of symbol time intervals, wherein in one of the symbol time intervals a plurality of the reference symbols are transmitted in a predetermined pattern, wherein the predetermined pattern has the reference symbols not adjacent to each other.2. The wireless communication unit of claim 1 , wherein the predetermined pattern has the reference symbols with a single space separating the reference symbols.3. The wireless communication unit of claim 1 , wherein the reference symbols are pilot symbols.4. The wireless communication unit of claim 1 , wherein the first symbols are quadrature modulated.5. The wireless communication unit of claim 1 , wherein the first symbols are produced by turbo coding the data bits.6. A method for use in a wireless communication unit claim 1 , the ...

QUALIFYING AVAILABLE REVERSE LINK CODING RATES FROM ACCESS CHANNEL POWER SETTING

Methods and apparatuses are disclosed regarding a wireless field unit, which may receive a plurality of forward link assignment messages for the wireless field unit over at least one first code channel. Each of the forward link assignment messages may indicate a modulation type, a data rate and assigned channel codes for a respective assigned forward link transmission. Also, forward link transmissions may be time multiplexed between wireless field units. The wireless field unit may receive a plurality of assigned forward link transmissions. In addition, the wireless field unit my process each of the received assigned forward link transmissions in response to the respective received forward link assignment messages. Further, the wireless field unit may receive power control information in assigned time intervals on a time division multiplexed second code channel, wherein the time division multiplexed second code channel is time multiplexed between a plurality of wireless field units. 1. A wireless field unit comprising:a transceiver operatively coupled to a processor, the transceiver and the processor configured to receive a plurality of forward link assignment messages for the wireless field unit over at least one first code channel, wherein each of the forward link assignment messages indicates a modulation type, a data rate and assigned channel codes for a respective assigned forward link transmission, wherein forward link transmissions are time multiplexed between wireless field units;the transceiver and the processor further configured to receive a plurality of assigned forward link transmissions; andthe processor further configured to process each of the received assigned forward link transmissions in response to the respective received forward link assignment messages.2. The wireless field unit of claim 1 , further comprising:the transceiver and the processor further configured to receive power control information in assigned time intervals on a time division ...

Qualifying available reverse link coding rates from access channel power setting

Methods and apparatuses are disclosed regarding a field unit, which may receive a plurality of forward link assignment messages for a plurality of time slots for a plurality of forward link transmissions, each message including an indication of a modulation and a code rate associated with a respective forward link transmission. The unit may receive at least one of the forward link transmissions in at least two of the time slots at the respective indicated modulation and code rate. The unit may receive a plurality of reverse link assignment messages for a plurality of time slots for a plurality of reverse link transmissions, each message including an indication of a modulation and a code rate associated with a respective reverse link transmission. The unit may transmit at least one of the reverse link transmissions in at least two of the time slots at the respective indicated modulation and code rate.

Qualifying available reverse link coding rates from access channel power setting

Methods and apparatuses are disclosed regarding a wireless field unit, which may receive a plurality of forward link assignment messages for the wireless field unit over at least one first code channel. Each of the forward link assignment messages may indicate a modulation type, a data rate and assigned channel codes for a respective assigned forward link transmission. Also, forward link transmissions may be time multiplexed between wireless field units. The wireless field unit may receive a plurality of assigned forward link transmissions. In addition, the wireless field unit my process each of the received assigned forward link transmissions in response to the respective received forward link assignment messages. Further, the wireless field unit may receive power control information in assigned time intervals on a time division multiplexed second code channel, wherein the time division multiplexed second code channel is time multiplexed between a plurality of wireless field units.

Minimal maintenance link to support synchronization

Multiple field units in a CDMA system are synchronized for communication with a base station using a shared forward and reverse link channel. Each field unit is assigned a time slot in a forward link channel to receive messages from the base station. Likewise, each field unit is assigned a time slot on a common reverse link channel for transmitting messages to the base station. Timing alignment among each of many field units and the base station is achieved by analyzing messages received at the base station in a corresponding time slot from each field unit. Thereafter, a message is transmitted in a corresponding time slot to a particular field unit from the base station for adjusting its timing so that future messages transmitted from the field unit are received in the appropriate time slot at the base station. In this way, minimal resources are deployed to maintain communication and precise synchronization between a base station and each of multiple users, minimizing collisions between field units transmitting in adjacent time slots on the reverse link.

Communicating reference and data information in a wireless network

A mobile device may generate reference bits. The mobile device may also produce a frame to send in an uplink transmission having two portions selectively with the reference bits or data bits.

Reverse link initial power setting using effective radiated power message to compute path loss

In an illustrative embodiment of the present invention, a reference signal including pilot information is transmitted from a base station to one or multiple field units over a pilot channel. A message is also sent to the field units over a paging channel to indicate an effective radiated power level at which the reference signal is transmitted on the pilot channel. Based on a received power level of the reference signal at a field unit and the effective radiated power level of the reference signal, a forward path loss is estimated at the field unit for the forward link between the base station and field unit. Assuming the path loss in the reverse link is approximately the same as the estimated forward link path loss, the field unit can transmit, a reply message in the reverse link so that the base station generally receives a message at-a desired power level.

Reverse link pilot integrated with block codes

A technique for encoding digital communication signals. Data symbols are augmented in pilot symbols inserted at predetermined positions. The pilot augmented sequence is then fed to a deterministic error correction block encoder, such as a turbo product coder, to output a coded sequence. The symbols in the error correction encoded sequence are then rearranged to ensure that the output symbols derived from input pilot symbols are located at regular, predetermined positions. As a result, channel encoding schemes can more easily be used which benefits from power of two length block sizes.

Method for searching pilot signals to synchronize a cdma receiver with an associated transmitter

A wireless transmit-receive unit includes an antenna, detection circuitry configured to detect a pseudorandom (PN) offset of a pilot signal received by the antenna while the antenna is adapted to an omnidirectional receive pattern, and monitoring circuitry configured to monitor a received signal strength of the pilot signal as a directional receive pattern of the antenna is steered in order to determine an azimuth angle of the directional pattern that maximizes the pilot signal at the detected PN offset.

MINIMAL MAINTENANCE LINK TO SUPPORT SYNCHRONIZATION

A method for use in a field unit operable in a wireless communication network. The method includes receiving an indication of a plurality of access identifiers from a base station. The field unit selects an access identifier from the plurality of access identifiers received from the base station. The selected access identifier is associated with a type of field unit request. The field unit transmits the selected access identifier to the base station. The field unit then receives a message from the base station. The message is based on the transmitted selected access identifier. The message contains a timing adjustment that indicates an amount to advance timing. A corresponding field unit apparatus, a base station method, and corresponding base station apparatus is also disclosed. 1. A method for supporting wireless communications , the method comprising:assigning a plurality of access identifiers to a field unit;transmitting an indication of the plurality access identifiers to the field unit;receiving a first message in at least one time slot, wherein the first message includes one of the plurality of access identifiers, and the one of the plurality of access identifiers is associated with a type of field unit request;analyzing the one of the plurality of access identifiers to determine a timing adjustment to be made at the field unit to synchronize the field unit with a base station; andtransmitting a second message to the field unit that includes the timing adjustment, wherein the timing adjustment indicates an amount to advance timing.2. The method of wherein the one of the plurality of access identifiers comprises a plurality of symbols.3. The method of claim 1 , wherein the timing adjustment is a single bit.4. The method of claim 1 , wherein the plurality of access identifiers comprise a plurality of groups of one or more access identifiers claim 1 , and each of the plurality of groups of one or more access identifiers is associated with a type of field unit ...

REVERSE LINK INITIAL POWER SETTING USING EFFECTIVE RADIATED POWER MESSAGE TO COMPUTE PATH LOSS

In an illustrative embodiment of the present invention, a reference signal including pilot information is transmitted from a base station to one or multiple field units over a pilot channel. A message is also sent to the field units over a paging channel to indicate an effective radiated power level at which the reference signal is transmitted on the pilot channel. Based on a received power level of the reference signal at a field unit and the effective radiated power level of the reference signal, a forward path loss is estimated at the field unit for the forward link between the base station and field unit. Assuming the path loss in the reverse link is approximately the same as the estimated forward link path loss, the field unit can transmit, a reply message in the reverse link so that the base station generally receives a message at-a desired power level. 1. A method for performing an access procedure in a transmitting at least one of a first type of signal to a base station wherein the first type of signal is associated with requesting access to a network associated with the base station and is transmitted at a first power level;', 'receiving a first message from the base station in response to the base station receiving the at least one of the first type of signal, wherein the first message includes timing and power adjustment information for transmitting an access request message to the base station over an uplink shared channel and identification information associated with the subscriber unit;', 'transmitting the access request message to the base station over the uplink shared channel in accordance with the timing and power adjustment information wherein the access request message includes a request for a communication link and the identification information associated with the subscriber unit wherein the access request message is a second type of message and is associated with requesting access to the network;', 'receiving a second message from the base ...

QUALIFYING AVAILABLE REVERSE LINK CODING RATES FROM ACCESS CHANNEL POWER SETTING

Methods and apparatuses are disclosed regarding data rate and resource allocation decisions which are made for a communications channel, such as a wireless reverse connection. The wireless reverse connection may be between stations. One of the stations may be a base station and another station may be a field unit. The field unit may transmit data to a base station at a first data rate, based on a first resource allocation. Also, the field unit may transmit, to the base station, an indication, such as a digital data word, that the field unit has the capability to support the transmission of uplink data at a second data rate. The base station may transmit a second resource allocation to the field unit. After receiving the second resource allocation, the field unit may transmit additional uplink data to the base station at the second data rate based on the second resource allocation. 1. A field unit comprising:an antenna; andcircuitry configured to transmit uplink data, to a base station, at a first data rate based on a first resource allocation;circuitry further configured to transmit, to the base station, an indication that the field unit is capable of supporting transmission of uplink data at a second data rate;circuitry further configured to receive, from the base station, a second resource allocation; andcircuitry further configured to transmit, to the base station, additional uplink data at the second data rate based on the received second resource allocation.2. The field unit of claim 1 , wherein the indication is based on at least a determination that the field unit is capable of using excess power to support transmission of uplink data at the second data rate.3. The field unit of claim 2 , wherein the determination is based on at least an amplifier output power of the field unit.4. The field unit of claim 1 , wherein the second data rate is a higher data rate.5. The field unit of claim 1 , wherein the second resource allocation is based on at least the ...

QUALIFYING AVAILABLE REVERSE LINK CODING RATES FROM ACCESS CHANNEL POWER SETTING

Methods and apparatuses are disclosed regarding a field unit, which may receive a plurality of forward link assignment messages for a plurality of time slots for a plurality of forward link transmissions, each message including an indication of a modulation and a code rate associated with a respective forward link transmission. The unit may receive at least one of the forward link transmissions in at least two of the time slots at the respective indicated modulation and code rate. The unit may receive a plurality of reverse link assignment messages for a plurality of time slots for a plurality of reverse link transmissions, each message including an indication of a modulation and a code rate associated with a respective reverse link transmission. The unit may transmit at least one of the reverse link transmissions in at least two of the time slots at the respective indicated modulation and code rate. 1. A wireless field unit comprising:a transceiver operatively coupled to a processor, the transceiver and the processor configured to receive a plurality of forward link assignment messages for a plurality of time slots for a plurality of forward link transmissions; wherein each forward link assignment message includes an indication of a modulation and a code rate associated with a respective forward link transmission;the transceiver and the processor further configured to receive at least one of the forward link transmissions in at least two of the time slots, wherein each received forward link transmission is received at the respective indicated modulation and code rate;the transceiver and the processor further configured to receive a plurality of reverse link assignment messages for a plurality of time slots for a plurality of reverse link transmissions; wherein each reverse link assignment message includes an indication of a modulation and a code rate associated with a respective reverse link transmission; andthe transceiver and the processor configured to transmit ...

COMMUNICATING REFERENCE AND DATA INFORMATION IN A WIRELESS NETWORK

A mobile device may generate reference bits. The mobile device may also produce a frame to send in an uplink transmission having two portions selectively with the reference bits or data bits. 1. A method performed by a mobile device , the method comprising:generating, by a processor of the mobile device, first reference bits and second reference bits;producing, by the mobile device, a portion of a frame to send in an uplink transmission, wherein the portion of the frame includes a first portion and a second portion;wherein the first portion includes the first reference bits and data bits;wherein the second portion includes the second reference bits without data bits;wherein alternating elements of the second portion include reference bits and elements between the alternating elements do not include reference bits; andsending, by the mobile device, the portion of the frame.2. The method of claim 1 , wherein the first reference bits and the second reference bits are pilot bits.3. The method of claim 1 , wherein a predetermined number of data elements are between reference elements of the first portion.4. The method of claim 1 , wherein the reference and non-reference bit elements of the second portion are time multiplexed.5. The method of claim 1 , wherein at least one of the first reference bits are derived from an orthogonal code.6. The method of claim 1 , wherein the first reference bits are derived from a first sequence and the second reference bits are derived from a second sequence.7. The method of claim 1 , wherein the frame is a Code Division Multiple Access (CDMA) frame.8. A method performed by a network device claim 1 , the method comprising:receiving, by the network device, a portion of a frame from a mobile device, wherein the portion of the frame includes a first portion and a second portion;wherein the first portion includes first reference bits and data bits;wherein the second portion includes second reference bits without data bits; andwherein ...

QUALIFYING AVAILABLE REVERSE LINK CODING RATES FROM ACCESS CHANNEL POWER SETTING

Methods and apparatuses are disclosed regarding a wireless field unit, which may receive a plurality of forward link assignment messages for a plurality of time slots for a plurality of forward link transmissions, each message including an indication of a modulation and a code rate associated with a respective forward link transmission. The field unit may receive at least one of the forward link transmissions in at least one time slot at the respective indicated modulation and code rate. The field unit may receive a plurality of reverse link assignment messages for a plurality of time slots for a plurality of reverse link transmissions, each message including an indication of a modulation and a code rate associated with a respective reverse link transmission. The field unit may transmit at least one of the reverse link transmissions in at least one time slot at the respective indicated modulation and code rate. 1. A wireless field unit comprising:a transceiver operatively coupled to a processor, the transceiver and the processor configured to receive a plurality of forward link assignment messages for a plurality of time slots for a plurality of forward link transmissions; wherein each forward link assignment message includes an indication of a modulation and a code rate associated with a respective forward link transmission;the transceiver and the processor further configured to receive at least one of the forward link transmissions in at least one time slot, wherein each received forward link transmission is received at the respective indicated modulation and code rate;the transceiver and the processor further configured to receive a plurality of reverse link assignment messages for a plurality of time slots for a plurality of reverse link transmissions; wherein each reverse link assignment message includes an indication of a modulation and a code rate associated with a respective reverse link transmission; andthe transceiver and the processor configured to ...

MINIMAL MAINTENANCE LINK TO SUPPORT SYNCHRONIZATION

A method for use in a field unit operable in a wireless communication network. The method includes receiving an indication of a plurality of access identifiers from a base station. The field unit selects an access identifier from the plurality of access identifiers received from the base station. The selected access identifier is associated with a type of field unit request. The field unit transmits the selected access identifier to the base station. The field unit then receives a message from the base station. The message is based on the transmitted selected access identifier. The message contains a timing adjustment that indicates an amount to advance timing. A corresponding field unit apparatus, a base station method, and corresponding base station apparatus is also disclosed. 1. A method for supporting wireless communications , the method comprising:assigning a plurality of access identifiers to a field unit;transmitting an indication of the plurality access identifiers to the field unit;receiving a first message in at least one time slot, wherein the first message includes one of the plurality of access identifiers, and the one of the plurality of access identifiers is associated with a type of field unit request;analyzing the one of the plurality of access identifiers to determine a timing adjustment to be made at the field unit to synchronize the field unit with a base station; andtransmitting a second message to the field unit that includes the timing adjustment, wherein the timing adjustment indicates an amount to advance timing.2. The method of wherein the one of the plurality of access identifiers comprises a plurality of symbols.3. The method of claim 1 , wherein the timing adjustment is a single bit.4. The method of claim 1 , wherein the plurality of access identifiers comprise a plurality of groups of one or more access identifiers claim 1 , and each of the plurality of groups of one or more access identifiers is associated with a type of field unit ...

MAXIMIZING DATA RATE BY ADJUSTING CODES AND CODE RATES

The present invention provides for making code rate adjustments and modulation type adjustments in a pseudonoise (PN) encoded CDMA system. Coding rate adjustments may be made by changing the number of information bits per symbol, or Forward Error Code (FEC) coding rate. A forward error correction (FEC) block size is maintained at a constant amount. Therefore, as the number of information bits per symbol are increased, an integer multiple of bits per epoch is always maintained. The scheme permits for a greater flexibility and selection of effective data rates providing information bit rates ranging from, for example, approximately 50 kilobits per second to over 5 mega bits per second (Mbps) in one preferred embodiment. 1. A subscriber unit comprising:a forward error correction (FEC) decoder conFig.d to decode a plurality of data blocks, wherein each of the plurality of data blocks is a fixed size and encoded with an error correction code, and to generate a plurality of decoded segments based on the plurality of data blocks, wherein each of the decoded segments is a variable number of data bits.2. The subscriber unit of claim 1 , wherein the FEC decoder is conFig.d to decode each of the plurality of data blocks based on a decoding rate.3. The subscriber unit of claim 2 , wherein a size of each of the plurality of decoded segments is based on the decoding rate.4. The subscriber unit of claim 3 , further comprising:a controller conFig.d to select a decoding rate and to signal the selected decoding rate to the FEC decoder.5. The subscriber unit of claim 4 , further comprising:a segment disassembler conFig.d to generate a data frame based on the plurality of decoded segments6. The subscriber unit of claim 1 , further comprising:a demodulator conFig.d to demodulate a received signal and to generate the plurality of data blocks.7. The subscriber unit of claim 6 , wherein the demodulator is conFig.d to demodulate the received signal using a Quadrature Phase Shift Keying ( ...

Access channel structure for wireless communication system

A technique for efficient implementation of pilot signals on a reverse link in a wireless communication system. An access channel is defined for the reverse link such that within each frame, or epoch, a portion is dedicated to sending only pilot symbols. Another portion of the frame is reserved for sending mostly data symbols; however, within this second portion of the frame, additional pilot symbols are interleaved among the data symbols. The pilot symbol or preamble portion of the access channel frame allows for efficient acquisition of the access signal at the base station, while providing a timing reference for determining the effects of multipath fading. In particular, a pilot correlation filter provides a phase estimate from the pilot symbols in the preamble portion, which is then used to decode the data symbols in the payload portion. An access acquisition portion of the receiver uses the phase estimates provided by the pilot correlation filter to process the output of a data symbol correlation filter. The additional pilot symbols embedded in the payload portion are used in a cross product operation to further resolve the effects of multipath fading.

Access channel structure for wireless communication system

A technique for efficient implementation of pilot signals on a reverse link in a wireless communication system. An access channel is defined for the reverse link such that within each frame, or epoch, a portion is dedicated to sending only pilot symbols. Another portion of the frame is reserved for sending mostly data symbols; however, within this second portion of the frame, additional pilot symbols are interleaved among the data symbols. The pilot symbol or preamble portion of the access channel frame allows for efficient acquisition of the access signal at the base station, while providing a timing reference for determining the effects of multipath fading. In particular, a pilot correlation filter provides a phase estimate from the pilot symbols in the preamble portion, which is then used to decode the data symbols in the payload portion. An access acquisition portion of the receiver uses the phase estimates provided by the pilot correlation filter to process the output of a data symbol correlation filter. The additional pilot symbols embedded in the payload portion are used in a cross product operation to further resolve the effects of multipath fading.

Maximizing data rate by adjusting codes and code rates in CDMA system

The present invention provides for making code rate adjustments and modulation type adjustments in a pseudonoise (PN) encoded CDMA system. Coding rate adjustments may be made by changing the number of information bits per symbol, or Forward Error Code (FEC) coding rate. A forward error correction (FEC) block size is maintained at a constant amount. Therefore, as the number of information bits per symbol are increased, an integer multiple of bits per epoch is always maintained. The scheme permits for a greater flexibility and selection of effective data rates providing information bit rates ranging from, for example, approximately 50 kilobits per second to over 5 mega bits per second (Mbps) in one preferred embodiment.

Access probe acknowledgment including collision detection to avoid oversetting initial power level

In an illustrative embodiment of the present invention, a first channel is allocated for transmitting sporadically generated messages from multiple field units to a base station. The first channel is preferably divided into time slots in which a field unit transmits an access request message to the base station for establishing a communication link. In response to an access request message, feedback information is provided from the base station to multiple field units indicating whether a collision was detected on the first channel for a message transmitted in a previous time slot. In an instance when a collision is detected, the field unit will re-transmit an access request message at a previous power level setting based on a random back off time. If no collision is detected and the base station fails to transmit an acknowledgment message from the base station to the access requesting field unit, the power output level of the field unit is increased for successive message transmissions until the message is received.

Apparatus and method for code tracking in an is-95 spread spectrum communication system

An apparatus and method for code tracking in an IS-95 spread spectrum communications system are disclosed. A pseudo-noise generator (516) generates an on-time component, an early component and a late component of a pseudo-noise code signal in response to an error signal. The on-time component is routed to a deinterleave and demodulate device (210) which demodulates and decodes baseband signals from received spread spectrum signals. An adder (518) substracts the early component from the late component to form a summation signal. A multiplier (520) multiplies the summation with the received signal to form a product signal. An integrator (522) integrates the product signal to form the error signal. The error signal is fed back into the pseudo-noise generator (516) to fine tune the on-time component, the early component and the late component of the pseudo-noise code signal. As a result, a spread spectrum signal is demodulated and decoded using only one correlator (504) instead of two.

Reverse link correlation filter in wireless communication systems

A single, common correlation filter (CF) core is provided in a wireless system using CDMA. A plurality of channels with different data rates are provided in the wireless system. The channels provided in the wireless system include the access channel, the maintenance channel, and the traffic channel in which information (e.g., pilot or data symbols or both) is transmitted at the tier 1, tier 2 and tier 3 rates. The data rate for transmitting the information is programmable by digital signal processor (DSP). A user-unique code, such as a PN code, is applied to the information being transmitted in the channels of the wireless system. The information is QPSK modulated and transmitted in any one of the channels at any data rate. The transmitted information is correlated at the smallest data rate (i.e., the tier 1 rate) in the correlation filter (CF) of the wireless system by time multiplexing delayed versions of the PN code to the correlation filter core. The correlated information is then demultiplexed and pilot aided QPSK demodulated. The demodulated information is summed at the proper integer multiple of the tier 1 rate to achieve the tier 2 and tier 3 rates. The three strongest multipaths (in terms of the received power) are selected in a window or time period for optimal information recovery. Furthermore, three outputs from the demodulated information can be provided and combined for temporal diversity. Spatial diversity is achieved by providing a plurality of antennas at each receiver and a single, common correlation filter at each of the plurality of antennas of the receivers in the wireless system.

Access channel structure for wireless communication system

Multiple pattern antenna

An antenna assembly includes at least two active or main radiating omni- directional antenna elements (100-1, 100-2) arranged with at least one beam control or passive antenna element (115) used as a reflector (305). The beam control antenna element(s) (115) may have multiple reactance elements (150-1 , 150-2) that can electrically terminate it to adjust the input or output beam pattern(s) (180, 190) produced by the combination of the active antenna elements (100-1, 100-2) and the beam control antenna element(s) (115). More specifically, the beam control antenna element(s) (115) may be coupled to different terminating reactances (150-1, 150-2) to change beam characteristics, such as the directivity and angular beamwidth. Processing m ay be employed to select which terminating reactance to use.

Reverse link correlation filter in multi rate cdma wireless communication systems

A single, common correlation filter (CF) core is provided in a wireless system using CDMA (code division multiple access). A plurality of channels with different data rates are provided in the wireless system. The channels provided in the wireless system include the access channel, the maintenance channel, and the traffic channel in which information (e.g., pilot or data symbols or both) is transmitted at the tier 1 (which is the basic despreading rate), tier 2 and tier 3 rates. The data rate for transmitting the information is programmable by an external programmable processor, e.g., a digital signal processor (DSP). A user-unique code, such as a PN (pseudo-random noise) code, is applied to the information being transmitted in the channels of the wireless system. Theinformation is modulated and transmitted in any one of the channels at any data rate. The transmitted information is correlated at the basic despreading rate (i.e., the tier 1 rate) in the correlation filter (CF) of the wireless system by time multiplexing delayed versions of the PN code (or orthogonal code, Walsh code) to the correlation filter core. The correlated information is then demultiplexed and demodulated. The demodulated information is summed at the proper integer multiple of the tier 1 rate to achieve the tier 2 and tier 3 rates. One or more signal components are selected (in terms of the received power, signal-to-noise ratio or multipath width) in a window or time period for optimal information recovery. The selecting step can also be implemented according to a preprogrammed time alignment. Furthermore, outputs from the demodulated information can be provided and combined for temporal diversity. Spatial diversity is achieved by providing a plurality of antennas, and a plurality of receivers at a location and providing a single, common correlation filter at each of the plurality of antennas of the receivers in the wireless system.

Multilevel decision feedback equalizer

A method of processing a sequence of digital symbols comprises the steps of processing the sequence of digital symbols and determining an uncertainty in the processing. If the uncertainty exceeds a predetermined threshold, then the method further comprises the steps of processing at least two sequences of digital symbols wherein at least one parameter is set differently in each sequence, and deciding upon a calculated error for each sequence which sequence is used to generate an output signal.

Multiple sample antenna and method for same

Method for using a non-orthogonal pilot signal with data channel interference cancellation

A system and method for encoding/decoding data channels in a CDMA system having data channel interference cancellation, wherein data channel interference cancellation is used to remove unwanted non-orthogonal pilot signal components which are present within a demodulated data signal. This is accomplished by regenerating interference terms with respect to the non-orthogonal pilot signal and subtracting them from the demodulated data signal.

Maintenance link using active/standby request channels

Multiple field units in a CDMA system are synchronized for communication with a base station using shared forward and reverse link channels. In an illustrative embodiment, each field unit is assigned a time slot in a forward link channel to receive messages from the base station. Likewise, each field unit is assigned a time slot on a common reverse link channel for transmitting messages to the base station. Timing alignment and power level control among each of many field units and the base station is achieved by analyzing messages received at the base station in a corresponding time slot as transmitted by each field unit. Thereafter, a message is transmitted from the base station in a corresponding time slot to a particular field unit for adjusting its timing or power level so that future messages transmitted from the field unit are received in the appropriate time slot at the base station at a desired power level. In this way, minimal resources are deployed to maintain communication and precise synchronization between a base station and each of multiple users, minimizing collisions between field units transmitting in adjacent time slots on the reverse link. This method reduces the frequency a field unit must rely on the use of a slotted aloha random access channel according to IS-95.

Tap-selectable viterbi equalizer

A tap-selectable Viterbi equalizer comprises means for determining at least one symbol from a previous determination assigned to a first state, means for determining a second state of the plurality of states and determining a surviving path metric by comparing path metrics originating from the determined symbol, means for determining the value of a previous symbol with respect to the symbol of the surviving state, and calculating means for generating a reduced trellis by calculating only path metrics for states in which the previous symbol has the determined value.

Apparatus and method for code tracking in an IS-95 spread spectrum message transmission system

Reverse link correlation filter in wireless communication systems

A single, common correlation filter (CF) core is provided in a wireless system using CDMA (code division multiple access). A plurality of channels with different data rates are provided in the wireless system. The channels provided in the wireless system include the access channel, the maintenance channel, and the traffic channel in which information (e.g., pilot or data symbols or both) is transmitted at the tier 1 (which is the basic despreading rate), tier 2 and tier 3 rates. The data rate for transmitting the information is programmable by an external programmable processor, e.g., a digital signal processor (DSP). A user-unique code, such as a PN (pseudo-random noise) code, is applied to the information being transmitted in the channels of the wireless system. Theinformation is modulated and transmitted in any one of the channels at any data rate. The transmitted information is correlated at the basic despreading rate (i.e., the tier 1 rate) in the correlation filter (CF) of the wireless system by time multiplexing delayed versions of the PN code (or orthogonal code, Walsh code) to the correlation filter core. The correlated information is then demultiplexed and demodulated. The demodulated information is summed at the proper integer multiple of the tier 1 rate to achieve the tier 2 and tier 3 rates. One or more signal components are selected (in terms of the received power, signal-to-noise ratio or multipath width) in a window or time period for optimal information recovery. The selecting step can also be implemented according to a preprogrammed time alignment. Furthermore, outputs from the demodulated information can be provided and combined for temporal diversity. Spatial diversity is achieved by providing a plurality of antennas, and a plurality of receivers at a location and providing a single, common correlation filter at each of the plurality of antennas of the receivers in the wireless system.

Maximizing data rate by adjusting codes and code rates

The present invention provides for making code rate adjustments and modulation type adjustments in a pseudonoise (PN) encoded CDMA system. Coding rate adjustments may be made by changing the number of information bits per symbol, or Forward Error Code (FEC) coding rate. A forward error correction (FEC) block size is maintained at a constant amount. Therefore, as the number of information bits per symbol are increased, an integer multiple of bits per epoch is always maintained. The scheme permits for a greater flexibility and selection of effective data rates providing information bit rates ranging from, for example, approximately 50 kilobits per second to over 5 mega bits per second (Mbps) in one preferred embodiment.

Apparatus and method for code tracking in an IS-95 spread spectrum message transmission system

Maximizing data rate by adjusting codes and code rates in CDMA system

The present invention provides for making code rate adjustments and modulation type adjustments in a pseudonoise (PN) encoded CDMA system. Coding rate adjustments may be made by changing the number of information bits per symbol, or Forward Error Code (FEC) coding rate. A forward error correction (FEC) block size is maintained at a constant amount. Therefore, as the number of information bits per symbol are increased, an integer multiple of bits per epoch is always maintained. The scheme permits for a greater flexibility and selection of effective data rates providing information bit rates ranging from, for example, approximately 50 kilobits per second to over 5 mega bits per second (Mbps) in one preferred embodiment.

Maintenance link using active/standby request channels

Multiple field units in a CDMA system are synchronized for communication with a base station using shared forward and reverse link channels. In an illustrative embodiment, each field unit is assigned a time slot in a forward link channel to receive messages from the base station. Likewise, each field unit is assigned a time slot on a common reverse link channel for transmitting messages to the base station. Timing alignment and power level control among each of many field units and the base station is achieved by analyzing messages received at the base station in a corresponding time slot as transmitted by each field unit. Thereafter, a message is transmitted from the base station in a corresponding time slot to a particular field unit for adjusting its timing or power level so that future messages transmitted from the field unit are received in the appropriate time slot at the base station at a desired power level. In this way, minimal resources are deployed to maintain communication and precise synchronization between a base station and each of multiple users, minimizing collisions between field units transmitting in adjacent time slots on the reverse link. This method reduces the frequency a field unit must rely on the use of a slotted aloha random access channel according to IS-95.

Arrangement for dynamic DC offset compensation

A DC tracking arrangement includes a first tracking unit for slow tracking receiving an input signal and generating a first output signal, a second tracking unit for fast tracking receiving the input signal and generating a second output signal, and a decision unit receiving the first and second output signal for selecting the first or second output signal.

Method for searching pilot signals to synchronize a cdma receiver with an associated transmitter

A method for synchronizing a CDMA receiver to a transmitter when an adaptive antenna is utilized to receive transmitted data, wherein a receiving antenna system is adapted between a 360° reception angle pattern (i.e., an omni-directional pattern) and a fixed reception angle (i.e., a directional pattern) by permitting the receiver to identify a pilot signal having the largest magnitude. The receiver minimizes interference from other pilot signals by steering antenna pattern nulls toward other transmitters. As a result, the time required for the receiver to acquire a valid pilot signal is significantly reduced.

Access probe acknowledgement with collision detection

In an illustrative embodiment of the present invention, a first channel is allocated for transmitting sporadically generated messages from multiple field units to a base station. The first channel is preferably divided into time slots in which a field unit transmits an access request message to the base station for establishing a communication link. In response to an access request message, feedback information is provided from the base station to multiple field units indicating whether a collision was detected on the first channel for a message transmitted in a previous time slot. In an instance when a collision is detected, the field unit will re-transmit an access request message at a previous power level setting based on a random back off time. If no collision is detected and the base station fails to transmit an acknowledgement message from the base station to the access requesting field unit, the power output level of the field unit is increased for successive message transmissions until the message is received.

Variable rate orthogonally coded reverse link structure

A method and apparatus for creating non-interfering coded signals to be simultaneously transmitted over a common frequency in a wireless communication systems, such as a CDMA system, at various data rates and without the use of orthogonal codes and/or orthogonal code generation techniques. The system provides cascaded arrangement of code modulations which each include a channel sequence combiner and selector. The channel sequence combiner receives an input signal and a repetitive maximum length channel sequence and combines these signals to produce a combined signal. The selector receives the input signal, the combined signal, and a repetitive strobe signal, and selects either the input signal or the combined signal to produce an encoded signal based upon a value of the repetitive strobe signal.

Maintenance link using active/standby request channels

Multiple field units in a CDMA system are synchronized for communication with a base station using shared forward and reverse link channels. In an illustrative embodiment, each field unit is assigned a time slot in a forward link channel to receive messages from the base station. Likewise, each field unit is assigned a time slot on a common reverse link channel for transmitting messages to the base station. Timing alignment and power level control among each of many field units and the base station is achieved by analyzing messages received at the base station in a corresponding time slot as transmitted by each field unit. Thereafter, a message is transmitted from the base station in a corresponding time slot to a particular field unit for adjusting its timing or power level so that future messages transmitted from the field unit are received in the appropriate time slot at the base station at a desired power level. In this way, minimal resources are deployed to maintain communication and precise synchronization between a base station and each of multiple users, minimizing collisions between field units transmitting in adjacent time slots on the reverse link. This method reduces the frequency a field unit must rely on the use of a slotted aloha random access channel according to IS-95.

Access channel structure for wireless communication system

A technique for efficient implementation of pilot signals on a reverse link in a wireless communication system. An access channel is defined for the reverse link such that within each frame, or epoch, a portion is dedicated to sending only pilot symbols. Another portion of the frame is reserved for sending mostly data symbols; however, within this second portion of the frame, additional pilot symbols are interleaved among the data symbols. The pilot symbol or preamble portion of the access channel frame allows for efficient acquisition of the access signal at the base station, while providing a timing reference for determining the effects of multipath fading. In particular, a pilot correlation filter provides a phase estimate from the pilot symbols in the preamble portion, which is then used to decode the data symbols in the payload portion. An access acquisition portion of the receiver uses the phase estimates provided by the pilot correlation filter to process the output of a data symbol correlation filter. The additional pilot symbols embedded in the payload portion are used in a dot product operation to further resolve the effects of multipath fading.

Access channel structure for wireless communication system.

Maximizing data rate by adjusting codes and code rates in CDMA system

The present invention provides for making code rate adjustments and modulation type adjustments in a pseudonoise (PN) encoded CDMA system. Coding rate adjustments may be made by changing the number of information bits per symbol, or Forward Error Code (FEC) coding rate. A forward error correction (FEC) block size is maintained at a constant amount. Therefore, as the number of information bits per symbol are increased, an integer multiple of bits per epoch is always maintained. The scheme permits for a greater flexibility and selection of effective data rates providing information bit rates ranging from, for example, approximately 50 kilobits per second to over 5 mega bits per second (Mbps) in one preferred embodiment.

STRUCTURADE ACCESS CHANNEL FOR WIRELESS COMMUNICATIONS SYSTEM.

Un método para procesar señales de canal de acceso en un sistema de comunicaciones digital inalámbrico que comprende los pasos de: en un transmisor, codificar símbolos piloto (53) en una porción de preámbulo (51) de una trama de canal de acceso de información a ser transmitida por el canal de acceso; y codificar símbolos de datos en una porción de carga útil (52) de la trama de canal de acceso, incluyendo también la porción de carga útil de la trama de canal de acceso símbolos piloto intercalados con los símbolos de datos. A method for processing access channel signals in a wireless digital communications system comprising the steps of: in a transmitter, encoding pilot symbols (53) in a preamble portion (51) of an information access channel frame a be transmitted by the access channel; and encoding data symbols in a payload portion (52) of the access channel frame, also including the payload portion of the access channel frame pilot symbols interspersed with the data symbols.

Pulse shaping filter with minimal intersymbol interference

An improved shaping filter (R) is provided in a radio frequency communication system. The filter response of the shaping filter (R) is generated by constraining the filter coefficients in their adaptation at the optimal sampling point and not constraining them at the non-sampling points. That is, the error metric is updated only at the optimum sampling point.

Adaptive beamforming in a wireless communication system

A method of transmitting information between a transmitting station having an adaptive antenna array and a receiving station in a wireless communication system. The method includes the steps of generating default weight vectors for the antenna array of the transmitting station, transmitting the weight vector to the receiving station, modifying the weight vector in the receiving station, re-transmitting the modified weight vector to the transmitting station, and adapting the adaptive antenna array according to the modified weight vector within the transmitting station.

Lna control-circuit for a receiver having closed loop automatic gaincontrol

A controlled receive device is disclosed having an amplifier circuit, which receives an input signal, and a control circuit which receives the input signal and outputs a controlled signal to a receiver. The receiver outputs an output signal. A controller varies the gain of the amplifier circuit in response to levels of the controlled signal and the output signal. The control circuit outputs a controlled indicator signal indicative of a level of the controlled signal and the receiver outputs an output indicator signal indicative of the output signal level. The controlled indicator signal and the output indicator signal are compared using comparators, to respective reference or threshold levels for producing control signals used by the controller for varying the amplifier gain.

Zugriffkanalstruktur für ein drahtloses übertragungssystem

Mitigating strong nongaussian interference in ss receivers

Systems, devices, methods, and computer-readable media for spread spectrum (SS) receiver interference mitigation are presented. An interference mitigation unit can include an interference analyzer that receives a complex-valued. signal and estimates statistical characteristics of at least a portion of the complex-valued signal, a unit controller that receives the estimated statistical characteristics from the interference analyzer, classifies the interference distribution based on statistical characteristics as a Gaussian, long-tail, or short-tail, selects a non-linearity for that distribution, and a programmable non-linear module that performs a non-linear functional conversion of an envelope of the received complex-valued signal using a non-linear input-output characteristic based on the classification by the unit controller.

Mitigating strong nongaussian interference in ss receivers

Systems, devices, methods, and computer-readable media for spread spectrum (SS) receiver interference mitigation are presented. An interference mitigation unit can include an interference analyzer that receives a complex-valued signal and estimates statistical characteristics of at least a portion of the complex-valued signal, a unit controller that receives the estimated statistical characteristics from the interference analyzer, classifies the interference distribution based on statistical characteristics as a Gaussian, long-tail, or short-tail, selects a non-linearity for that distribution, and a programmable non-linear module that performs a non-linear functional conversion of an envelope of the received complex-valued signal using a non-linear input-output characteristic based on the classification by the unit controller.

Korrelationsfilter für den rückkanal in einem drahtlosen cdma system mit mehreren bit-raten

Korrelationsfilter für den rückkanal in einem drahtlosen cdma system mit mehreren bit-raten

Mottaker for et tidsdelt duplekssystem uten angitt tidsluketildeling

Receiver for time division multiplex system without explicit time slot assignment

A technique for a time division multiplex system in which access to shared broadcast communication media is granted on a demand basis. Particular connections are assigned slot times at the transmitter based on demand. However, no specific information regarding the assignment of time slots need be communicated to the receivers. The transmit side employs a forward error correction technique followed by multiplication by a cover sequence unique to each connection. All receivers listen to the broadcast transmission channel all of the time. The receiver assigned to each connection decodes the data associated with that connection. Data frames that fail the forward error correction process are discarded, and only those frames which are successfully decoded are passed up to a higher layer.

Receiver for time division multiplex system without explicit time slot assignment

Receiver for time division multiplex system without explicit time slot assignment

A technique for a time division multiplex system in which access to shared broadcast communication media is granted on a demand basis. Particular connections are assigned slot times at the transmitter based on demand. However, no specific information regarding the assignment of time slots need be communicated to the receivers. The transmit side employs a forward error correction technique followed by multiplication by a cover sequence unique to each connection. All receivers listen to the broadcast transmission channel all of the time. The receiver assigned to each connection decodes the data associated with that connection. Data frames that fail the forward error correction process are discarded, and only those frames which are successfully decoded are passed up to a higher layer.

明示的なタイムスロット割り当てを伴わない時分割多重システムのための受信機

【課題】共有ブロードキャスト通信媒体へのアクセスがオンデマンドで与えられる時分割多重システムのための技術の提供。 【解決手段】特定の接続に、送信機においてオンデマンドに基づいてスロット時間が割り当てられる。しかし、タイムスロットの割り当てに関する特定の情報を、受信機群に通信する必要はまったくない。送信側は、前方誤り訂正技術を使用し、続いて、各接続に固有のカバーシーケンスを掛けることを行う。すべての受信機が、ブロードキャスト伝送チャネルに常時従う。各接続に割り当てられた受信機が、その接続に関連するデータを復号化する。前方誤り訂正プロセスに不合格であったデータフレームは、破棄され、正常に復号化されるフレームだけが、より高いレイヤに送られる。 【選択図】図１

Receiver for time division multiplex system without explicit time slot assignment

A technique for a time division multiplex system in which access to shared broadcast communication media is granted on a demand basis. Particular connections are assigned slot times at the transmitter based on demand. However, no specific information regarding the assignment of time slots need be communicated to the receivers. The transmit side employs a forward error correction technique followed by multiplication by a cover sequence unique to each connection. All receivers listen to the broadcast transmission channel all of the time. The receiver assigned to each connection decodes the data associated with that connection. Data frames that fail the forward error correction process are discarded, and only those frames which are successfully decoded are passed up to a higher layer.

Mottaker for et tidsdelt duplekssystem uten angitt tidsluketildeling

En teknikk for et tidsdelt multiplekssystem hvori tilgang til fordelt anvendte kringkastkommunikasjonsmedia sikres opprettet på en anmodningsbasis. Bestemte forbindelser er tildelt tidsluker ved senderen og basert på anmodning. Ingen spesifikk informasjon som gjelder tildeling av tidsluker behøver imidlertid å kommuniseres til mottakerne. Sendersiden utnytter en fremover rettet feilkorreksjonsteknikk etterfulgt av multiplikasjon med en dekksekvens som er særegen for hver forbindelse. Alle mottakere lytter til kringkastingsoverføringskanalen hele tiden. Den mottaker som er tildelt hver forbindelse dekoder de data som har sammenheng med denne forbindelse. Datapuljer som ikke bedømmes korrekte i den fremover rettede feilkorreksjonsprosess blir vraket, og bare de puljer som blir vellykket dekodet blir videreført opp til et høyere lag.

無明顯時槽分派分時多工系統之接收器

Receiver for time division multiplex system without explicit time slot assignment

Receiver for time division multiplex system without explicit time slot assignment

A technique for a time division multiplex system in which access to shared broadcast communication media is granted on a demand basis. Particular connections are assigned slot times at the transmitter based on demand. However, no specific information regarding the assignment of time slots need be communicated to the receivers. The transmit side employs a forward error correction technique followed by multiplication by a cover sequence unique to each connection. All receivers listen to the broadcast transmission channel all of the time. The receiver assigned to each connection decodes the data associated with that connection. Data frames that fail the forward error correction process are discarded, and only those frames which are successfully decoded are passed up to a higher layer.

Mitigating strong nongaussian interference in ss receivers

Systems, devices, methods, and computer-readable media for spread spectrum (SS) receiver interference mitigation are presented. An interference mitigation unit can include an interference analyzer that receives a complex-valued signal and estimates statistical characteristics of at least a portion of the complex-valued signal, a unit controller that receives the estimated statistical characteristics from the interference analyzer, classifies the interference distribution based on statistical characteristics as a Gaussian, long-tail, or short-tail, selects a non-linearity for that distribution, and a programmable non-linear module that performs a non-linear functional conversion of an envelope of the received complex-valued signal using a non-linear input-output characteristic based on the classification by the unit controller.

Mitigating strong nongaussian interference in ss receivers

Systems, devices, methods, and computer-readable media for spread spectrum (SS) receiver interference mitigation are presented. An interference mitigation unit can include an interference analyzer that receives a complex-valued signal and estimates statistical characteristics of at least a portion of the complex-valued signal, a unit controller that receives the estimated statistical characteristics from the interference analyzer, classifies the interference distribution based on statistical characteristics as a Gaussian, long-tail, or short-tail, selects a non-linearity for that distribution, and a programmable non-linear module that performs a non-linear functional conversion of an envelope of the received complex-valued signal using a non-linear input-output characteristic based on the classification by the unit controller.

Receiver for time division multiplex system without explicit time slot assignment

A technique for a time division multiplex system in which access to shared broadcast communication media is granted on a demand basis. Particular connections are assigned slot times at the transmitter based on demand. The transmit side employs a forward error correction technique followed by multiplication by a cover sequence unique to each connection. All receivers (14-1...14-1) listen to the broadcast transmission channel all of the time. The receiver assigned to each connection decodes the signals in such a manner that only the receiver with the correct cover sequence assigned to a particular connection will successfully decode the data associated with that connection.

Receiver for time division multiplex system without explicit time slot assignment

A technique for a time division multiplex system in which access to shared broadcast communication media is granted on a demand basis. Particular connections are assigned slot times at the transmitter based on demand. The transmit side employs a forward error correction technique followed by multiplication by a cover sequence unique to each connection. All receivers (14-1...14-1) listen to the broadcast transmission channel all of the time. The receiver assigned to each connection decodes the signals in such a manner that only the receiver with the correct cover sequence assigned to a particular connection will successfully decode the data associated with that connection.

Automatic frequency control loop multipath combiner for a rake receiver

A Rake receiver having fingers is disclosed. The Rake receiver includes frequency discriminators (110-1, 110-2, 110-3) for automatic frequency control and a combiner (205). Each finger includes a frequency discriminator (110-1, 110-2, 110-3). The combiner (205) combines outputs from the frequency discriminators (110-1, 110-2, 110-3) to output an average error signal which is fed back to the frequency discriminators (110-1, 110-2, 110-3) for removing frequency offsets from all the fingers. The combiner (205) includes an adder (207) which adds the outputs of the frequency discriminators (110-1, 110-2, 110-3), and a divide circuit which divides the combined adder output by the number of the outputs which were added together to form the average error signal. The combiner further includes a filter connected between the adder and the divide circuit. In addition, further adders are provided where each of theses adders receives the average error signal and a respective one of the outputs from the frequency discriminators in order to provide an estimate of one of the frequency offsets.

Pilot symbol assisted modulation and demodulation in wireless communication systems

A transmitter (10) which includes a quadrature phase shift keying (QPSK) modulator (14), and a receiver (20) which includes a pilot correlation filter (PCF) (23), a data matching filter (DMF) (22), a timing recovery mechanism, a sampler (24), and a QPSK demodulator (26) are provided in a wireless communication system. The transmitter (10) transmits a frame of data symbols and pilot symbols (frame) to a receiver in a wireless system. The QPSK modulator (14) modulates the frame. At the receiver (20), the PCF (23) recovers the pilot symbols, whereas the timing recovery mechanism tracks the timing of the pilot symbols in the frame. The DMF (22) enhances the multipath response of the received frame at known time intervals of the pilot symbols, and output a plurality of enhanced peaks. The sampler (24) samples the multipath response of the received frame at each of the enhanced peaks. The QPSK demodulator (26) demodulates the sampled frame and recovers the data symbols using QPSK demodulation based on the sampled frame.

Pilot symbol assisted modulation and demodulation in wireless communication systems

A transmitter (10) which includes a quadrature phase shift keying (QPSK) modulator (14), and a receiver (20) which includes a pilot correlation filter (PCF) (23), a data matching filter (DMF) (22), a timing recovery mechanism, a sampler (24), and a QPSK demodulator (26) are provided in a wireless communication system. The transmitter (10) transmits a frame of data symbols and pilot symbols (frame) to a receiver in a wireless system. The QPSK modulator (14) modulates the frame. At the receiver (20), the PCF (23) recovers the pilot symbols, whereas the timing recovery mechanism tracks the timing of the pilot symbols in the frame. The DMF (22) enhances the multipath response of the received frame at known time intervals of the pilot symbols, and output a plurality of enhanced peaks. The sampler (24) samples the multipath response of the received frame at each of the enhanced peaks. The QPSK demodulator (26) demodulates the sampled frame and recovers the data symbols using QPSK demodulation based on the sampled frame.

Pilot symbol assisted modulation and demodulation in wireless communication systems