Abstract: Systems (100) and methods for selectively controlling access to multiple data streams which are communicated using a shared frequency spectrum and spreading code. The methods involve forming a global data communication signal (134) by amplitude modulating a global data signal (130) comprising global data symbols and forming a phase modulated signal (120) by phase modulating a protected data signal. The phase modulated signal represents protected data symbols. The methods also involve forming a protected data communication signal (126) by changing phase angles of the protected data symbols using a variable angle Ø determined by a random number source and combining the protected data signal with a spreading sequence (CSC). The methods further involve combining the global and protected data communication signals to form an output communication signal (140) having a spread spectrum format. The output communication signal is transmitted over a communications channel (104).

Abstract: A symbol sequence contained in a received signal comprising a cyclic convolution of a Walsh code multiplexed signal and a channel impulse response of a multipath channel is detected using Walsh Hadamard domain equalization techniques. The method comprises converting the received signal and the channel impulse response of the multipath channel from the time domain to the WHT domain, and determining the symbol sequence based on equalizing the received signal in the WHT domain using WHT spectra of the channel impulse response to remove inter-symbol interference from the received signal due to cross-correlation between Walsh codes.

Abstract: A system and method for signaling and transmitting uplink reference signals are provided. A method for communications controller operations includes signaling information about a set of sequence groups to a first communications device, where the first communications device uses a sequence in the set of sequence groups to modulate a reference signal. The method also includes selecting a sequence group from the set of sequence groups and signaling information about the selected sequence group to the first communications device.

Abstract: Systems (100) and methods (400) for selectively controlling access to multiple data streams which are communicated using a shared frequency spectrum and shared spreading codes. The methods involve generating a first product signal (FPS) by spreading first symbols of a first amplitude modulated (AM) signal using a first spreading code (SC). The methods also involve generating a second product signal (SPS) by spreading second symbols of a complimentary AM signal using a second SC. The FPS (124) and SPS 126 are combined to form a protected data communication signal (PDCS) including first data recoverable by a receiver (106). A global data communication signal (GDCS) is combined with PDCS (128) to form an output signal (140) having a spread spectrum format. The GDCS is generated using a digital modulation process and includes second data recoverable by a plurality of receivers (106, 108).

Abstract: A method can include receiving, at a transmitter, during a symbol time that comprises a plurality of chip times, a data value for each of a plurality of distinct data channel inputs. During each chip time, the method can include (a) indexing a different row of a matrix of data bits; (b) decoding one channel input using a first subset of one or more columns of the indexed row; (c) determining a code value for the decoded one channel from a second subset of one or more columns of the indexed row; and (d) providing the coded data value to a transmission circuit for transmission to a receiver. Actions (a) to (d) can be performed for each of the plurality of chip times in the symbol time. In some implementations, the matrix of data bits is a Hadamard matrix with randomly shuffled rows.

Abstract: To provide a radio base station apparatus, mobile terminal device and wireless communication method for enabling the SRS to be used efficiently in an LTE-A system, a wireless communication method of the invention is characterized in that a radio base station apparatus performs OFDM modulation on a transmission signal including transmission information on sounding reference signals for each transmission antenna, and transmits the OFDM-modulated transmission signal, and that a mobile terminal device receives the signal including the transmission information, controls a transmission aspect of the sounding reference signals for each transmission antenna based on the transmission information, and transmits the sounding reference signals in the transmission aspect for each transmission antenna.

Abstract: A transmitter includes: spread code multiplying means that multiplies a symbol indicating a reference signal by spread code to generate a chip sequence after spreading; chip pattern generation means that generates a chip pattern by performing chip repetition a predetermined repetition number of times on the chip sequence after spreading; and multiplying means that multiplies a signal having the chip pattern by a phase specific to the transmitter.

Abstract: A mobile terminal measures interference over multiple measurement periods and generates interference probability data based on the statistical distribution of the interference measured. The interference probability data may describe, for example, the probability of each possible level of interference expected at the mobile terminal. The mobile terminal derives channel quality information as feedback to a base station based on this interference probability data (e.g., when noise at the mobile terminal falls below a threshold). In one embodiment, the mobile terminal does so by estimating from the interference probability data the probability of successfully receiving a transmission if certain feedback information is reported. Derived in this way, the feedback information more reliably indicates interference likely present at the mobile terminal when the base station sends the transmission.

Abstract: A system for implementing an orthogonal frequency division multiplexing scheme and providing an improved range extension. The system includes a transmitter for transmitting data to a receiver. The transmitter includes a symbol mapper for generating a symbol for each of a plurality of subcarriers and a spreading module for spreading out the symbol on each of the plurality of subcarriers by using a direct sequence spread spectrum. The symbol on each of the plurality of subcarriers is spread by multiplying the symbol by predefined length sequences. The receiver includes a de-spreader module for de-spreading the symbols on each of the plurality of subcarriers. The de-spreader module includes a simply correlator receiver for obtaining maximum detection. The correlator produces an output sequence of a same length as an input sequence and the de-spreader module uses a point of maximum correlation on the output sequence to obtain a recovered symbol.

Abstract: A system and method for adaptively controlling feedback information according to a loading condition of a communications cell is provided. A method comprises receiving an indication from a base station, computing an amount of feedback information to transmit back to the base station using the indication, locating a feedback resource assigned to the mobile station using the amount of feedback information and an identity of the mobile station, computing a feedback information, and transmitting the feedback information using the located feedback resource. The indication is for a set of candidate transmission formats that is based on loading conditions in the cell.

Abstract: In embodiments, an adaptive tone erasure technique is applied to orthogonal frequency division multiplexing (OFDM) communications, such as ECMA-368 standard ultra-wideband (UWB) communications. A transmitter obtains jammed sub-carrier information and calculates an erasure mask. The jammed sub-carriers are nulled before transmitting to a receiver. In accordance with the erasure mask, bits falling on the jammed sub-carriers are replaced by erasure bits before interleaving, keeping the interleaver block size constant notwithstanding variations in the number of the jammed sub-carriers. The receiver also obtains the jammed sub-carrier information and the erasure mask. After the receiver deinterleaves the constant size blocks, it decodes the data without the erasure bits. The transmitter may detect the jammed sub-carriers itself, or obtain the information from the receiver. The receiver similarly may detect the jammed sub-carriers itself, or obtain the information from the transmitter.

Abstract: Systems and methods for use in CDMA antenna systems are provided in which signals each having a common overhead component are transmitted on a set of adjacent beams of a sector with a micro-timing offset between signals transmitted on adjacent pairs of beams which is large enough that destructive cancellation substantially does not occur between the pair of beams.

Abstract: Methods for code-division multiplex communications. The method involve generating orthogonal or statistically orthogonal chaotic spreading codes (CSC1, . . . , CSCK) having different static offsets using a set of polynomial equations (f0(x(nT)), . . . , fN-1(x(nT)) and/or f0[x((n+v)T+t)], . . . , fN-1[x((n+v)T+t)]). The methods also involve forming spread spectrum communications signals respectively using the orthogonal or statistically orthogonal chaotic spreading codes. The methods further involve concurrently transmitting the spread spectrum communications signals over a common RF frequency band. The spreading codes are generated using different initial values for a variable “x” of a polynomial equation f(x(nT)) and/or different acc-dec values for a variable “v” of a polynomial equation f[x((n+v)T+t)]. The static offsets are defined by the different initial values for a variable “x” and/or different acc-dec values for a variable “v”.

Abstract: Examples are disclosed for transmitting and receiving schemes for multiuser single-carrier space time spreading (STS) with frequency domain equalization.

Abstract: Systems and methods are provided for detecting and geo-locating a target transmitting a CDMA or other spread-spectrum signal within an area of interest. Targets are identified by spatially-dividing the area of interest into a number of cells. First and second receiving beams are sequentially directed toward each of the cells from two or more different intercept sites. The presence of the spread-spectrum signal within each cell is identified from the signals received at each directional beam, and if the spread-spectrum signal is present in both the first and the second receiving beams, then the target can be indicated to be present within the cell.

Abstract: Methods and apparatus are presented for improving the feedback of channel information to a serving base station, which allows a reduction in the reverse link load while allowing the base station to improve the forward link data throughput. Over a channel quality indicator channel, three subchannels are generated; the re-synch subchannel, the differential feedback subchannel, and the transition indicator subchannel. The information carried on each subchannel can be used separately or together by a base station to selectively update internal registers storing channel conditions. The channel conditions are used to determine transmission formats, power levels, and data rates of forward link transmissions.

Abstract: Described is a method that includes receiving a signal through a channel; considering at least one channel-related criterion and, in response to the considered at least one channel-related criterion, setting a value of an adaptive combining threshold for a maximum ratio combiner that receives the outputs of a plurality of fingers of a rake receiver.

Abstract: Disclosed are a method and a device for transmitting uplink control information (UCI) by a terminal in a wireless communication system. The UCI transmission method comprises the steps of: generating an encoding information bit stream by performing channel coding for a UCI bit stream; generating complex modulation symbols by performing modulation for the generated encoding information bit stream; spreading the complex modulation symbols in block-wise on the basis of an orthogonal sequence; and transmitting the spread complex modulation symbols to a base station. The encoding information bit stream is generated by a channel coding for circularly repeating the UCI bit stream.

Abstract: A method of providing a packetized data transmission service to a mobile terminal (108) in a spread spectrum communication network (100), includes: at a transmitter (102), broadcasting an indication message to a cell on a downlink broadcast channel (114), the indication message providing notification of an available packetized data transmission service intended for the mobile terminal (108); at the mobile terminal (108), monitoring the broadcast channel (114) for the indication message, and upon receipt, acknowledging detection of the indication message to the transmitter (102) on an uplink contention channel (116); and at the transmitter (102), upon contention completion, transmitting packetized data transmission service configuration information to the mobile terminal (108) on the broadcast channel (114).

Abstract: A base station for use in a wireless network, wherein the base station transmits in a downlink to a plurality of subscriber stations using a plurality of antennas according to a multiple input, multiple-output (MIMO) protocol. During a first downlink subframe, the base station operates in single-user MIMO mode in which the base station transmits a first data subpacket to a first subscriber station using a first antenna and transmits a second data subpacket to the first subscriber station using a second antenna. During a second downlink subframe following the first downlink subframe, the base station operates in multi-user MIMO mode in which the base station transmits a third data subpacket to the first subscriber station using the first antenna and transmits a fourth data subpacket to a second subscriber station using the second antenna.

Abstract: Wireless communication systems and methods utilize one or more remote terminals, one or more base terminals, and a communication channel between the remote terminal(s) and base terminal(s). The remote terminal applies a direct sequence spreading code to a data signal at a spreading factor to provide a direct sequence spread spectrum (DSSS) signal. The DSSS signal is transmitted over the communication channel to the base terminal which can be configured to despread the received DSSS signal by a spreading factor matching the spreading factor utilized to spread the data signal. The remote terminal and base terminal can dynamically vary the matching spreading factors to adjust the data rate based on an estimation of operating quality over time between the remote terminal and base terminal such that the amount of data being transmitted is substantially maximized while providing a specified quality of service.

Abstract: A system is provided for transmitting a low code rate spatially multiplexed channel on multiple antennas. The system includes a transmitter and a processor. The processor is configured such that the processor encodes a block of information bits to form channel coded bits, wherein the ratio of the number of channel coded bits to the number of information bits is greater than one; and the processor maps the channel coded bits to modulation symbols, and each channel coded bit is mapped once to a modulation symbol. The transmitter is configured to transmit a first portion of the modulation symbols using a spreading sequence on a first antenna of the multiple antennas and to transmit a second portion of the modulation symbols using the spreading sequence on a second antenna of the multiple antennas.

Abstract: A method for generating a preamble of a data unit for transmission via a communication channel includes generating a first field of the preamble using one of a first sequence or a second sequence, such that the first sequence and the second sequence are complementary sequences such that a sum of out-of-phase aperiodic autocorrelation coefficients of the first sequence and the second sequence is zero; generating, using the other one of the first sequence or the second sequence, an indicator of a start of a second field of the preamble, the second field associated with channel estimation information, such that the indicator of the start of the second field immediately follows the first field; and generating the second field of the preamble.

Abstract: Communication circuitry uses a combination of Pseudo-Noise (PN) coded and non-PN coded transmission periods to represent different data values. In one embodiment, a number of data values are encoded into a smaller second number of encoded ternary values. The Pseudo-Noise (PN) codes are transmitted representing some of the encoded ternary values and no transmitted PN codes represent other encoded ternary values. The throughput of spread spectrum radio systems is increased by representing data values in fewer spread spectrum time slots.

Abstract: What is disclosed is a method of operating a communication system. The method includes receiving a request to initiate a communication session with a wireless communication device, wherein the request indicates an application type. The method also includes determining a spreading code based on the application type, and transferring the spreading code to the wireless communication device. The method also includes receiving communications for the communication session encoded with the spreading code and decoding the encoded communications based on the spreading code.

Abstract: A portable device, such as a mobile terminal or user equipment, for encoding uplink acknowledgments to downlink transmissions. The portable device includes a receiver configured to receive a plurality of data blocks, such that each of the data blocks include an associated cyclic redundancy check (CRC), and a processor configured to determine received status for each of the data blocks by checking the CRC of each of the data blocks. The portable device further includes a transmitter for transmitting a response sequence which indicates the received status of all of the data blocks.

Abstract: A radio transmission apparatus for transmitting a first radio signal and a second radio signal with different communication system, the apparatus includes: a first transmission unit which generates the first radio signal on the basis of a first communication system and transmits the first radio signal; a diffusion processing unit which performs diffusion processing of data allocated to DC subcarrier on the basis of the first communication system, and generate a diffusion signal; an addition unit which adds the diffusion signal and a signal obtained by orthogonal frequency division multiplex processing; and a second transmission unit which transmits the added signal as the second radio signal.

Abstract: A radio communication system having a radio transmitter and a radio receiver and adopting multiple carrier modulation and code spreading modulation methods is disclosed. The radio communication system comprises a selecting unit provided in the radio transmitter or the radio receiver, for selecting an interleaving mode out of plural interleaving modes depending on radio propagation path conditions; a symbol configuration unit provided in the radio transmitter; and a symbol reconfiguration unit provided in the radio receiver. The symbol configuration unit configures information symbols to be transmitted by the radio transmitter in both time and frequency directions in a pattern according to the interleaving mode selected by the selecting unit, and the symbol reconfiguration unit reconfigures information symbols received by the radio receiver in both time and frequency directions in an inverse pattern of the pattern.

Abstract: Methods and apparatuses are provided for uplink MIMO transmissions in a wireless communication system. In particular, a primary stream (610) may be utilized to carry a primary data channel E-DPDCH (624), and a secondary stream (612) may be utilized to carry a secondary data channel S-E-DPDCH (620). Further, the primary stream (610) may be precoded utilizing a primary precoding vector, and the secondary stream (612) may be precoded utilizing a secondary precoding vector, with coefficients orthogonal to those of the primary precoding vector. The primary stream may include an enhanced control channel E-DPCCH (614) adapted to carry control information associated with both the primary data channel E-DPDCH (624) and the secondary data channel S-E-DPDCH (620).

Abstract: An arrangement (90) for noise rise estimation in a wireless communication system comprises a power measuring means (45) for measuring received total wideband power. A means (52) for computing estimates of a noise floor measure bases its computation on a number of the measured received total wideband powers. A means (80) for calculating values of a biased noise rise measure bases its calculations on a number of received total wideband powers or an estimation derived therefrom and a respective one of the estimates of a noise floor measure. A means (91) for providing a measure representing a long term behaviour of the values of the biased noise rise measure is provided. A means (93) for obtaining a value of a present, unbiased noise rise measure, bases its function on the measure representing a long term behaviour of the values of the biased noise rise measure. A corresponding method is also disclosed.

Abstract: Sequence generation in wireless communication is provided for sequences having good aperiodic correlation properties. In particular, dual window quasi-Barker sequences are generated that possess at least some properties of Barker sequences. In addition, the sequences can be orthogonal to mitigate multiple access interference. Dual windowing allows the sequences even after being phase modulated by data to be recognized, provided that delay in transmission is large as compared to the correlation zone. In this regard, the sequences can be utilized in quasi-synchronous spread spectrum and/or code division multiple access (CDMA) signal communication to provide orthogonality while substantially eliminating inter-user and inter-symbol interference. In addition, unlike the single window low periodic correlation sequences, system overheads, such as cyclic prefix, need not be utilized in transmission as the data modulation effect can be accounted for by the dual windowing.

Abstract: The present invention relates to an apparatus for rejecting images in a receiver. The apparatus of the present invention relates to an apparatus for rejecting image signals in a receiver of a direct conversion structure and comprises a signal mismatch compensation unit configured to detect gain error and phase error between an In-phase (I) signal and a Quadrature (Q) signal received through the receiver, to reject image signals existing in the I and Q signals, and to output a result. The signal mismatch compensation unit detects the gain error and the phase error using an adaptive step method of reducing the step size of the gain error and the phase error step by step whenever the gain error and the phase error are converged. According to the present invention, high image rejection ratio is achieved and the adaptation time taken to obtain a high image rejection ratio is reduced simultaneously.

Abstract: The present invention is a double-layer multi-carrier ultra-wideband wireless communication method, wherein the frequency band for ultra-wideband communication is divided into a plurality of sub-bands, then one or more sub-bands are used for data transmission, and the Orthogonal Frequency Division Multiplex (OFDM) multi-carrier transmission technology is used in each sub-band. In the transmitting party, the data symbols to be transmitted are allocated on M branches corresponding to the M sub-bands, and the OFDM modulation is implemented on the data symbols on each branch to obtain M branches of parallel data, then digital baseband multi-carrier modulation is implemented on the M branches of parallel data. Thereby, the spectrum of data on each branch is moved onto the digital sub-band corresponding to the radio sub-band one to one, so the digital baseband signal of the radio signal to be transmitted is obtained.

Abstract: Complex digital data values derived from a DSSS signal, in particular, a GNSS signal, are delivered to a general purpose microprocessor at a rate of 8 MHz and chip sums over eight consecutive data values spaced by a sampling length (TS), each beginning with one of the data values as an initial value, formed and stored. For code removal, each of a series of chip sums covering a correlation interval of 1 ms and each essentially coinciding with a chip interval of fixed chip length (TC), where a value of a basic function (bm) reflecting a PRN basic sequence of a satellite assumes a correlation value (Bm), is multiplied by the latter and the products added up over a partial correlation interval to form a partial correlation sum. The partial correlation interval is chosen in such a way that it essentially coincides with a corresponding Doppler interval having a Doppler length (TD) where a frequency function used for tentative Doppler shift compensation and represented by a step function (sine, cosine) is constant.

Abstract: A method of evaluating the usage in a received signal of codes from a tree of codes that can be used to orthogonalise communications signals, the method including testing to determine if a given code is in use in the received signal and deducing from the result and from the tree structure the need to test in the received signal for the use of the codes in the portion of the tree depending from said given code. The invention also includes corresponding apparatus and software.

Abstract: A communication technique based on direct sequence spread spectrum signaling employs, for all users sharing an access channel, a single spreading code that has a duration sufficiently longer than the symbol length that the likelihood of confusion between users is minimized if not eliminated. The length of the spreading code is sufficiently long that contention events can occur only when two bursts occur at the receiver within one chip time of one another.

Abstract: A code division multiplex signal transmitter includes an operational circuit, a modulator unit and a multiplexer. The operational circuit adds up input transmission data on channels to produce resultant added data and modulates pieces of bit transmission data which are indicative of the values of the respective bits of the added data, when expressed in binary form, the pieces of bit transmission data being equal in number to the M bit positions of the added data expressed in binary form. The modulator unit includes modulators corresponding in number to the M bit positions of the added data in the binary form. A k-th modulator, where k is an integer of 1 to M, inclusive, modulates a k-th piece of bit transmission data to produce a k-th bit modulated signal whose amplitude level is 2k-1. The multiplexer multiplexes first to M-th bit modulated signals to produce a code division multiplex signal.

Abstract: Examples are disclosed for transmitting and receiving schemes for multiuser single-carrier space time spreading (STS) with frequency domain equalization.

Abstract: A method and system for controlling power dissipation in a base station of a navigation satellite system (NSS) is disclosed. One method utilizes a sensor to monitor one or more components of the base station. Then, based on information from the sensor, a transmission bit rate is increased from a pre-defined bit rate to an increased transmission bit rate for an NSS message transmitted from the base station without reducing transmission power level of the base station. The method also periodically provides a bit rate update signal at the pre-defined bit rate, the bit rate update signal informing a rover utilizing the base station of the increased transmission bit rate for the NSS message transmitted from the base station.

Abstract: In a wireless communication system, a portable device and an in-vehicle device wirelessly communicate with each other by a spread spectrum method. The in-vehicle device transmits a synchronization signal indicative of a reference period to the portable device. The in-vehicle device performs code acquisition for only a portion of a spread wireless signal received from the portable device. The portion has a starting point in a search period from a search start point to a search end point. The search start point is identified based on the reference period and a predetermined first correction time. The search end point is identified based on the reference period and a predetermined second correction time.

Abstract: To generate a pulse for ranging, a kernel is convolved with a spreading sequence. The spreading sequence is parametrized by one or more ordered (length, sparsity) pairs, such that the first sparsity differs from the bit length of the kernel and/or a subsequent sparsity differs from the product of the immediately preceding length and the immediately preceding sparsity. Alternatively, a kernel is convolved with an ordered plurality of spreading sequences, all but the first of which may be non-binary. The pulse is launched towards a target. The reflection from the target is transformed to a received reflection, compressed by deconvolution of the spreading sequence, and post-processed to provide a range to the target and/or a direction of arrival from the target.

Abstract: Described herein are code-modulated multi-signal systems. In one embodiment, a multi-signal system receives multiple input signals and code-modulates each input signal with a unique code to distinguish the input signal from the other input signals. The input signals may come from multiple antennas, multiple sensors, multiple channels, etc. The code-modulated signals are then combined into a combined signal that is sent through shared blocks and/or transmitted across a shared medium in a shared path. After shared processing and/or shared transmission, the individual signals are recovered using matched filters. Each matched filter contains a code corresponding to one of the unique codes for recovering the corresponding signal from the combined signal. The recovered signals may then be inputted to additional processors for further processing.

Abstract: The present invention provides a method and apparatus for multiplexing code division and frequency division transmissions. One embodiment of the method includes accessing at least one first symbol and at least one second symbol, encoding the at least one first symbol according to a frequency division protocol, and encoding the at least one second symbol using a coding sequence having a cyclic correlation property. The method also includes transmitting a radiofrequency signal indicative of the at least one encoded first symbol and the at least one encoded second symbol.

Abstract: Certain aspects of the present disclosure relate to a technique for multiple antennas on a body-mounted node to improve ranging availability. The present disclosure also supports utilizing transmit antenna diversity for reliable ranging, wherein the antenna diversity can be achieved by employing two separate transmitter chains.

Abstract: Methods, systems, and apparatuses, including computer programs encoded on computer-readable media, for receiving monitor data from a lighting equipment monitor. A data stream is created based upon the monitor data. The data stream is spread with a common pseudo-noise (PN) code that is used by a plurality of nodes in communication with an access point. A frequency offset to the spread data stream based at least in part on a timing of the access point is applied. The spread data stream is transmitted with a randomly selected timing offset.

Abstract: An early-late gate based ADC timing approach is described for performing early-late gate timing recovery despite the presence of multipath signal distortion. Multipath conditions may severely distort Barker correlator magnitudes generated for taps within two taps of a determined bit synchronization time. Exemplary embodiments of the described approach may combine Barker correlator magnitudes for several receive chains to calculate the timing error correction corresponding to a difference of early and late taps. The approach may be used to increase the size and stability of Barker correlator magnitudes generated for taps far away from a determined bit synchronization time.

Abstract: A method for facilitating transmission of data in a communication system is provided herein. In operation, a base radio of a plurality of base radios combines status information corresponding to a plurality of inbound frequencies and transmits the combined status information on a single outbound radio frequency. Further, each of the plurality of inbound radio frequencies corresponds to one of the plurality of base radios. Then, one or more radio terminals monitor the single outbound radio frequency to receive the combined status information, determine at least one available inbound radio frequency from the plurality of inbound radio frequencies based on the received combined status information, selects an inbound radio frequency of the at least one available inbound frequency, and transmitting the data using the selected inbound radio frequency to the corresponding base radio.

Abstract: A multi-channel audio decoder reconstructs multi-channel audio of more than two physical channels from a reduced set of coded channels based on correlation parameters that specify a full power cross-correlation matrix of the physical channels, or merely preserve a partial correlation matrix (such as power of the physical channels, and some subset of cross-correlations between the physical channels, or cross-correlations of the physical channels with coded or virtual channels).

Abstract: The present disclosure relates generally to a system and method for scrambling in a wireless communication system. In one example, the method includes receiving a bit group representing at least a portion of a signal, where a total number of bits in the bit group is defined by a modulation scheme applied to the signal. A bit of the bit group is identified that indicates a sign of an imaginary part of the signal and another bit of the bit group is identified that indicates a sign of a real part of the signal. Only the two bits indicating the signs of the imaginary and real parts of the signal are scrambled using a random sequence prior to wirelessly transmitting the bit group.

Abstract: A system and method for transmitting a plurality of spread-spectrum signals over a communications channel having fading. The plurality of spread-spectrum signals are radiated by a plurality of antennas, with each antenna preferably spaced by one-quarter wavelength. A plurality of receiver antennas receive the plurality of spread-spectrum signals and a plurality of fading spread-spectrum signals. Each receiver antenna is coupled to a plurality of matched filters having a respective plurality of impulse responses matched to the chip-sequence signals of the plurality of spread-spectrum signals. A RAKE and space-diversity combiner combines, for each respective chip-sequence signal, a respective plurality of detected spread-spectrum signals and a respective multiplicity of detected-multipath-spread-spectrum signals, to generate a plurality of combined signals. The symbol amplitudes can be measured and erasure decoding employed to improve performance.