Abstract: The present invention is a method for accurately estimating a location of a mobile-telephone using forward link power control. In one embodiment, the present invention comprises the steps of transmitting first, second and third signals from first, second and third base stations during first, second and third time intervals; decreasing the power level of the first base station during at least portions of the second and third time intervals; receiving a mobile-telephone signal having receive information indicating times-of-arrivals of the first, second and third signals at the mobile-telephone; and estimating a location of the mobile-telephone using the receive information and known locations of the first, second and third base stations. Advantageously, this embodiment of the present invention actually decreases the interference level contribution of the first base station, and requires little change to the network side of existing wireless communication standards and no change to the mobile-telephone side.

Abstract: The invention is a repeater for a telecommunications transmission system such as a CDMA wireless system. The repeater reduces leakage by using a feedback signal whose amplitude and phase are adjusted in response to the amplitude and phase of a sampled input signal when a switch turns off the normal output of the repeater for a short period of time. In one embodiment, a pilot signal is transmitted during this time period so that the sampled input is the leakage signal. In another embodiment, the sampled input is the normal transmission signal received during the time period.

Abstract: A CDMA communication system capable of operating at higher data rates with less bit errors and reduced cochannel interference facilitates coherent detection without the use of a pilot tracking signal. A transmitter in the communication system includes a coherence interval channel encoder, an orthogonal function encoder, such as a Walsh encoder, as well as a pseudo noise (PN) channel modulator. The channel encoder processes data sequences into sufficiently short encoded data blocks to minimize any phase shifts at a receiver in a high mobility environment due to a Doppler frequency shift. Depending on the application, several transmitters may be synchronized such that the corresponding transmitted information signals are orthogonal to one another.

Abstract: The present invention is a reduced iteration decoder circuit and method to compute error-locator sequence values for use in the correction of bit errors in Reed-Solomon or BCH coded information. By utilizing special properties of Reed-Solomon code and BCH codes, the decoder circuit of the present invention can detect n symbol errors using approximately n mathematical iterations with substantially reduced decoding processing time. A further reduction of decoding time is achieved by the performance of a substantial portion of the decoding processing in a parallel manner. The present invention may be utilized in digital communication systems and data storage systems or other information systems where Reed-Solomon or BCH encoding is utilized.

Abstract: A signal despreader for use in a CDMA system processes samples of the received signal with filtered replicas of the code coefficient sequences associated with the system users. The symbols transmitted by each system user are recovered using a filtered replica of that user's associated code coefficient sequence. In the disclosed embodiment, the communications channel between each system user's transmitter and the base station is bandlimited. Accordingly, within each user's transmitter, filtering apparatus having a frequency characteristic is utilized to limit the frequency spectrum of each coded signal to a predetermined bandwidth equal to or less than that of the communications channel. Each filtered replica, pursuant to the present invention, reflects this frequency characteristic. In addition, the communications channel also has a frequency characteristic, and each filtered replica can reflect this characteristic as well.

Abstract: Despreading of the received signal in a CDMA system is provided using code coefficient sequences which are derived from those utilized by the system users to encode their respective symbols. Each derived code coefficient sequence is a function of the correlation between a different user's code coefficient sequence and the code coefficient sequences of all other users. Advantageously, this technique substantially reduces interference effects and is suitable for use in the despreader of differentially or nondifferentially coded CDMA systems.

Abstract: To recover the bits from various users in an asynchronous CDMA communications system, samples of the received signal are processed using blocks of code coefficients. Each code coefficient block includes the sequence of code coefficients for each user which formed the received signal samples. Each sequence has the same number of code coefficients and this number is equal to the product of a predetermined number of bit intervals and the number of code coefficients per bit interval. Processing of the received signal samples using this block formation completely eliminates interference including the so-called leading and lagging edge effects and can be implemented with blocks that include the code coefficients in one or more bit intervals.

Abstract: A CDMA system embodying apparatus and methods operates to reduce the effects of the multiple access interference in order to increase the channel capacity and achieve greater efficiency in the use of a given frequency bandwidth. Reception of CDMA radio transmissions is in multiple stages is which the multiple access interference is estimated after the first stage. This estimated multiple access interference is subtracted from the original received input, and the detection of the intended signal is performed on the signal having the reduced multiple access interference.

Abstract: A channel assignment system provides channel assignments to make effective use of the available frequency spectrum by assigning one channel at a time until all the channels in the allotted frequency spectrum are used. A pre-allocation step assigns specified channels to certain cells and these assignments are checked against initial input system constraints. Then the remaining channels are assigned one at a time to the cells according to defined system performance constraints and the number of channels required by each cell. Each cell is defined by its logical faces. The traffic load for each logical face is defined according to selected factors which may include call rates, blocking rates, handoff thresholds, access thresholds, call drop rates, etc. Given these factors the number of channels required by each logical face can be derived and input to the channel assignment system. A level of interference is determined for each logical face as caused by every other logical face by a signal matrix computer.

Abstract: A method for compressing data employing vector quantization is achieved by calculating the norm of an input vector and identifying a reference codebook vector which has a norm which is closest to the norm of the input vector. The distance between the input vector and the reference codebook vector selected is computed and employed to identify a vector space about the reference vector containing a subset of codebook vectors one or more of which may be closer to the input vector than the initially selected reference vector. The closest codebook vector is selected iteratively without the necessity of searching every vector in the codebook.