MXPA99007730A - Out of channel cyclic redundancy code method for a discrete multitone spread spectrum communications system - Google Patents

Out of channel cyclic redundancy code method for a discrete multitone spread spectrum communications system

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Publication number
MXPA99007730A
MXPA99007730A MXPA/A/1999/007730A MX9907730A MXPA99007730A MX PA99007730 A MXPA99007730 A MX PA99007730A MX 9907730 A MX9907730 A MX 9907730A MX PA99007730 A MXPA99007730 A MX PA99007730A
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MX
Mexico
Prior art keywords
signal
error
base station
data
highly efficient
Prior art date
Application number
MXPA/A/1999/007730A
Other languages
Spanish (es)
Inventor
James Ryan David
Gibbons David
Lee Maxwell Robert
Original Assignee
At&T Wireless Services Inc
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Publication date
Application filed by At&T Wireless Services Inc filed Critical At&T Wireless Services Inc
Publication of MXPA99007730A publication Critical patent/MXPA99007730A/en

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Abstract

In a discrete multitone spread spectrum system, a base station distinguishes between normal collisions and noise bursts when receiving access request signals for remote units on a common access channel. The base station is then able to reply to the remote units with information about the quality of the common access channel and why their transmissions where not successful. The remote units then use this information to adapt their retry processes to the channel's quality, depending on whether there was a noise burst, a normal collision, or a successful transmission on the channel.

Description

METHOD OF CODE OF REDUCTION CYCLIC OUTSIDE THE CHANNEL FOR AN EXTENDED SPECTRUM COMMUNICATIONS SYSTEM, OF DISCRETE MULTIPLE TONES Background of the Invention Field of the Invention This invention involves improvements to communication systems and methods in a wireless discrete multi-tone extended spectrum communications system.
Description of Related Art Wireless communication systems, such as cellular and personal communication systems, operate on limited spectral bandwidths. They must make a highly efficient use of scarce band width resource to provide a good service to a large population of users. The Code Division Multiple Access Protocol (CDMA) has been used by wireless communication systems to make efficient use of Rfsf.031125 of limited bandwidths. The protocol uses a unique code to distinguish each user's data signal from other user's data signals. The knowledge of the unique code with which any specific information is transmitted, allows the separation and reconstruction of each user's message at the receiving end of the communication channel. Adaptive beam or beam formation technology has become a promising technology for wireless service providers to offer high coverage, high capacity, and high quality service. Based on this technology, a wireless communications system can significantly improve its coverage capacity, system capacity, and operation. The described personal wireless access network (PWAN) system uses the formation of an adaptive beam of light combined with a form of the CDMA protocol known as the extended spectrum of discrete multitones (DMT-SS) to provide efficient communication between a base station and a plurality of remote units, (the Agee patent, et al., uses the term "discrete multiple tone stacked carrier" (DMT-SC) to refer to this protocol). Every effort should be made to avoid loading high-priority, normal traffic channels with the management information of the system having a lower priority. An example of system management information is the characterization of channel quality factors that are not immediately necessary to control the real-time operation of the network. What is needed is a way to download communication of system management information from high priority traffic channels.
Brief Description of the Invention The invention described herein is a new method for making more efficient use of the low spectral bandwidth in a wireless discrete multi-tone extended spectrum communications system. Each remote station and each base station in the network prepares an error detection code, such as a cyclic redundancy code (CRC), on each data block that is to be transmitted over the traffic channels. The calculated CRC value for a given block of data is a unique coordinate assignment of the data block that characterizes the block of data. Any change in the data block will lead to a different CRC value. Each block of data that is to be sent is numbered with a block number to distinguish it from other blocks of data that are sent by a sending station. A data message is formed by concatenating the data block with the block number. A value of the CRC is calculated for each block of data. An error detection message is formed by concatenating the CRC value with the block number. The sending station prepares the data message by forming data vectors that will be dispersed using the discrete multitone extended spectrum (DMT-SS) protocol to distribute the message of the data over a plurality of discrete tone frequencies, forming a dispersion signal for the traffic channel. According to the invention, the sending station prepares the error detection message for transmission over the link control channel of the network. The sending station prepares the error detection messages by forming a vector of the link control channel that will be dispersed using the discrete multiple tone extended spectrum (DMT-SS) protocol to distribute the message of the data on a plurality of the discrete tone frequencies, forming an extended signal for the link control channel. A link control channel is associated with the communication session using the traffic channels. Normally, the link control channel carries the necessary control information for the sending and receiving stations during a session using the traffic channels. However, its capacity is sub-used. According to the invention, the instant of transmission of the error detection message is allowed to be different from the instant of transmission of the data message. This allows error detection messages to be transmitted when the capacity is available over the link control channel. The receiving station separates the error detection messages that it receives from the link control channel, so that they are or are accessible by their block numbers. When the receiving station receives a data message on the traffic channel, it performs a CRC calculation on the block of data in the message to obtain a new resulting CRC value. The new CRC value is also separated at the receiving station with the block number so that it is accessible by its block number. Then, when both the received error message and the new CRC value are both available at the receiving station, they are compared by their common block number. The CRC value received in the error detection message is compared with the new calculated CRC of the received data block. If the comparison determines that there is a difference in the values, then an error signal is generated. The error signal can be processed and is used in several ways. The error signal may initiate a negative acknowledgment signal to be sent from the receiving station back to the transmitter, requesting the sender to repeat the transmission of the data block. The error signal can initiate an update on the dispersion and de-dispersion weights at the receiving station in an effort to improve the signal and the interference ratio with respect to the traffic channel noise. The error signal can initiate an alarm to be used by another real-time control. Or, the error signal can be recorded for the compilation of a longer term report of the quality of the traffic channel. Usually, the invention has advantageous applications in the field of wireless communications, such as cellular communications or personal communications, where the width of the band is scarce compared to the number of users and their needs. Such applications can be made in mobile, fixed systems, or that can be moved only minimally. However, the invention can also advantageously be applied to other communication systems, not wireless.
Brief Description of the Drawings In the drawings: Figure 1 is an architectural diagram of the PWAN system, which includes the remote stations that transmit to a base station. Figure 2 is an architectural diagram of the remote station X as an emitter. Figure 3 is an architectural diagram of the base station Z as a receiver. Figure 4 is a more detailed architectural diagram of the disassembly of the vector and the CRC comparison logic in a receiving station. Figure 5 is an architectural diagram of the base station Z as an emitter. Figure 6 is an architectural diagram of the remote station X as a receiver. Figure 7 is a flow diagram showing the remote station as the emitter and the base station as the receiver.
Figure 8 is a flow diagram showing the base station as the emitter and the remote station as the receiver.
Description of the Preferred Modality Figure 1 is an architectural diagram of the personal wireless access network (PWAN) system. Two users, Alice and Bob, are located at remote station X and wish to transmit their respective data messages to base station Z. Station X is placed to be equidistant from antenna elements A, B, C, and D from the base station Z. Two other users, Chuck and Dave, are located at the remote station Y and also wish to transmit their respective data messages to the base station Z. Station Y is geographically remote from Station X and is not equidistant from the antenna elements A, B, C, and D of the base station Z. The remote stations X and Y and the base station Z use the CDMA protocol form known as the extended spectrum of discrete multitones (DMT-SS ) to provide efficient communications between the base station and the plurality of remote station units. This protocol is designated in Figure 1 as the multi-tone CDMA. In this protocol, the user's data signal is modulated by a set of weighted discrete frequencies or tones. The weights or weights are scatter weights that distribute the data signal over many discrete tones that cover a wide range of frequencies. The weights or comparisons are complex numbers with the actual component acting to modulate the amplitude of a tone while the complex component of the weight or weight acts to modulate the phase of the same tone. Each tone in the set of weighted tones supports or transports the same data signal. Several users in the transmission station can use the same set of tones to transmit their data, for each of the users who share the set of tones we have a different set of weights or weightings of the dispersion. The set of weighted tones for a particular user is transmitted to the receiving station where t is processed with non-dispersed weights or weights related to the weights of the user, to retrieve the user's data signal. For each of the antennas spatially separated in the receiver, the received multiple tone signals are transformed from the signals of the domain to the frequency domain signals. Weights or weights without dispersion are assigned to each component of the frequency of the signals received by each element of the antenna. The values of the weights or weights without dispersion are combined with the received signals to obtain an optimized approximation of the individual transmitted signals, characterized by the set of particular multiple tones and the location of the transmission. The PWAN system has a total of 2560 discrete tones (bearers) equally spaced at 8 MHZ from the available bandwidth in the range of 1850 to 1990 MHZ. The spacing between the tones is 3.125 kHz. The total set of tones are numbered consecutively from 0 to 2559 starting from the lowest frequency tone. The tones are used to carry traffic messages and higher messages between the base station and the plurality of remote units. The traffic tones are divided into 32 traffic divisions, with each traffic channel that requires at least a 72-tone traffic division. In addition, the PWAN system uses higher tones to establish synchronization and pass control information between the base station and the remote units. A Common Link Channel (C.C) is used by the base to transmit the control information to the Remote Units. A Common Access Channel (CAC) is used to transmit messages from the Remote Unit to the Base. There is a grouping of the tones assigned to each channel. These higher channels are used in common by all the units when they are exchanging the control messages with the base station. In the PWAN system, the Time Division Duplex (TDD) is used by the base station and the remote unit to transmit the data and control information in both directions on the same multi-tone frequency channel. The transmission from the base station to the remote unit is called the forward transmission and the transmission from the remote unit to the station is called the reverse transmission. The time between recurring transmissions from either the remote unit or the base station is the TDD period. In each TDD period, there are four trains of consecutive transmission pulses in each direction. The data is transmitted in each pulse train using multiple tones. The base station and each remote unit must be synchronized and conformed to the TDD timing structure and both the base station and the remote unit must be synchronized to an adaptation or framing structure. All remote units and base stations must be synchronized so that all remote units transmit at the same time and then all base stations transmit at the same time. When a remote unit is initially powered, it acquires synchronization from the base station so that it can exchange the control and traffic messages within the prescribed TDD format. The remote unit must also acquire the phase and frequency synchronization for the DMT-SS signals so that the remote unit is operating at the same frequency and phase as the base station. The selected tones within each set of tones are designated as pilots distributed across the entire frequency band. Pilot tones carry the known data configurations that make an accurate estimation of the channel possible. The series of pilot tones, which have known phases and amplitudes, have a known level and are spaced far apart at approximately 30 KHz to provide an accurate representation of the channel response (i.e., the amplitude and phase distortion introduced by the characteristics of the communication channel) over the entire transmission band.
According to the invention, each remote station and each base station in the network prepare an error detection code, such as the cyclic redundancy code (CRC), on each block of data to be transmitted on the traffic channels. . A variety of detection codes can be used, according to the invention. Polynomial codes, also known as cyclic redundancy codes, are preferred for the invention. The sender and receiver must agree on a polynomial generator before communication. A checksum is calculated for a data block based on the generator polynomial. The checksum is a unique coordinate assignment of the data block. Any changes in the bit configuration of the data block will lead to a different checksum. Examples of the error detection codes for the preferred embodiment of the invention are given in Tanenbaum, "Computer Networks", second edition, Prentice-Hall, 1989. The calculated CRC value for a given block of data is an assignment single coordinates of the block of data that characterizes the data block. Any change in the data block will lead to a different CRC value. Each block of data to be sent is numbered with a block number to distinguish it from the other blocks of data that are sent by a sending station. A data message is formed by concatenating the block of data with the block number. A CRC value is calculated for each block of data. An error detection message is formed by concatenating the CRC value with the block number. The sending station prepares the data message by forming data vectors that will be dispersed using the discrete multiple tone extended spectrum (DMT-SS) protocol to distribute the message of the data over a plurality of discrete tone frequencies, forming a Scatter signal for the traffic channel. According to the invention, the sending station prepares the error detection message for transmission over the link control channel of the network. The sending station prepares the error detection message by forming a vector of the link control channel that will be broadcast or dispersed using the discrete multiple tone extended spectrum (DMT-SS) protocol to distribute the message of the data over a plurality of discrete tone frequencies, forming a dispersion or diffusion signal for the link control channel. A link control channel is associated with the communication session using the traffic channels. Normally, the link control channel carries the control information needed by the receiving and sending stations during a session using the traffic channels. However, its capacity is sub-used. According to the invention, the instant of transmission of the error detection message is allowed to be different from the transmission of the data message. This allows error detection messages to be transmitted when the capacity is available over the link control channel. The reception station separates the detection messages that it receives from the control channel of the link, so that they are accessible by their block numbers. When the receiving station receives a data message on the traffic channel, it performs a CRC calculation on the block of the data in the message to obtain a new resulting CRC value. The new CRC value is also separated at the receiving station with the block number so that it is accessible by its block number. Then, when both the received error message and the new CRC value are both available at the receiving station, they are compared by their common block number. The CRC value received in the error detection message is compared with the new calculated CRC of the received data block. If the comparison determines that there is a difference in the values, then an error signal is generated. The error signal can be processed and used in various ways. The error signal may initiate a negative acknowledgment signal to be sent from the receiving station back to the transmitter, requesting the sender to repeat the transmission of the data block. The error signal may initiate an update in the weights or weights of the dispersion and the despread in the receiving station in an effort to improve the signal and the interference to noise ratio in the traffic channel. The error signal can initiate an alarm that will be used for another real-time control. Or, the error signal can be recorded for the compilation of a long-term report of the quality of the traffic channel. Figure 2 is an architectural diagram of remote station X as the emitter. Alice and Bob enter data to the remote station X. The data is sent to the vector forming separator 202 and also to the cyclic redundancy code generator 204. The data vectors are output from the separator 202 to the lattice encoder. 206. The data vectors are in the form of a data message formed by the concatenation of a 64K bit data block with its block number assigned in series. The output of the LCC vectors from the CRC generator 204 to the lattice encoder 206 are in the form of an error detection message formed by the concatenation of the CRC value with the block number. The lattice encoded data vectors and the LCC vectors are then output to the spectral dispersion processor 208. The resulting data tones and the LCC tones are then output from the processor 208 to the transmitter 210 for transmission to the base station. The first four steps in the flow diagram 700 of Figure 7 show the steps in the remote station X when it is the emitter. The steps in the transmission method from a remote station to a base station are the first for the Remote Station in step 710 to generate a CRC value in the data block, to assign a data block number to the value of CRC, and to concatenate the CRC value and the block number in an error message which is an input as a vector to the link control channel (LCC). Then at step 720, the Remote Station performs the lattice encoding of the vector of the CRC link control channel and the vectors of the data block. Then in Step 730, the Remote Station effects the spectral diffusion of the link control channel vector of the lattice-encoded CRC and the vectors of the data block. Then in step 740, the Remote Station transmits the tone of the CRC link control channel and the tones of the data block to the base station. The system of the personal wireless access network (PWAN) described, provides a more detailed description of a high capacity mode, wherein a division of the traffic is used in a traffic channel. The Base transmits the information to the Multiple Remote Units in its cell. The transmission formats are for the 64 kbit / s traffic channel, along with a 4 kbps Link Control Channel (LCC) between the Base and the Remote Unit. The binary source supplies the data to the transmitter of the transmitter at 64 kbit / s. This results in a train of impulses from the transmission. The information bits are encoded in accordance with a standard triple data encoder (DES) algorithm. The encoded bits are then located randomly in a block of random location of the data. A block of conversion of bits to octales converts the binary sequence located randomly into a sequence of 3-bit symbols. The sequence of symbols is converted into 16 symbol vectors. The term vector usually refers to a vector of column which is generally complex. A symbol of the LCC is added to form a vector of 17 symbols. The vector of 17 symbols is coded by lattice. The lattice encoding starts with the most significant symbol (first element of the vector) and is sequentially continued until the last element of the vector (the LCC symbol). This process employs convolutional coding that converts the input symbol (an integer between 0 and 7) to another symbol (between 0 and 15) and assigns coordinates to the encoded symbol with respect to its constellation point of the 16QAM signal (or 16PSK). The output of the lattice encoder is therefore a vector of 17 elements where each element is the signal within the set of 16 QAM (or 16PSK) constellation signals. (The term signal will usually refer to a point in the constellation of the signal). A pilot link maintenance signal (LPM) is added to form a vector of 18 signals, with the LMP as the first elements of the vector. The resulting vector (18 X 1) is premultiplied by a front blur matrix (18 x 18) to give a vector b (18 x 1).
The vector b is multiplied in the manner of elements by the preemphasis vector of the gain (18 x 1) to give another vector (18 x 1), c, where p denotes the Index of the traffic channel and is a whole number . The vector is post-multiplied by a forward spatial and spectral dispersion vector (1 x 32) to give an R (p) matrix (18 x 32). The number 32 results from multiplying the spectral dispersion factor 4 and the spatial dispersion factor 8. The matrices of 18 x 32 that correspond to the totality of the traffic channels carried (over the same division) are combined (aggregates) then to produce the matrix S of 18 x 32. The matrix S is divided (by groups of four columns) into eight submatrices (18 x 4) (A0 to A7). (Indices 0 to 7 correspond to the antenna elements on which these symbols will eventually be transmitted). Each sub-matrix is assigned coordinates with respect to the tones within a traffic division. A lower physical layer places the signals of the baseband in accumulators or vessels of the discrete Fourier Transfer Frequency (DTF) where the data is converted into the time domain and sent to its corresponding antenna elements (0 to 7) for transmission over the air. This process is repeated from the beginning for the next 48 bits of binary data that will be transmitted in the next forward transmission pulse train. Figure 3 is an architectural diagram of the base station Z as a receiver. The data tones and the LCC tones are received in the antennas of the base station A, B, C, and D. The receiver 310 passes the tones of the data and the tones of the LCC to the spectral and spatial de-scattering processor 312 The de-scattering signals are then output from the processor 312 to the lattice decoder 314. The data vectors 400, 400 and 400"are then output to the disassembly separator of the vector 316, shown in greater detail in FIG. Figure 4. LCC vectors 402, 402 and 402"are output to the CRC comparison processor 320, shown in greater detail in Figure 4. Alice data and Bob data are output from separator 316 to the public switched telephone network (PSTN). The Alice data and the Bob data are also input to the CRC 318 generator. The CRC 318 generator calculates a new CRC value for each 64 K-bit data block and outputs the new CRC value and number of blocks to separator 406 of the CRC 320 comparison processor. Figure 4 is a more detailed architectural diagram of vector disassembly and CRC comparison logic at a receiving station. The reception station separates in the CRC 320 comparison processor the error detection messages it receives from the link control channel, so that they are accessible by their block numbers N, N + 1, N +2, etc. When the receiving station receives a data message on the traffic channel, it performs a CRC calculation on the data block in the message with the CRC generator 318 to obtain a new resulting CRC value. The new CRC value is separated at 406 at the receiving station with the block number so that it is accessible by its block number. Then, when both the received error message and the new CRC value are both available at the receiving station, they are compared by the selector 404 by their common block number. The CRC value received in the error detection message 402 is compared to the new calculated CRC of the received data block 400 by means of the comparator 408. If the comparison determines that there is a difference in the values, then an error signal is generated by the generator 322. The error signal may be processed and used in various ways by the error processor 330. The error signal may initiate a recognition signal to be sent from the receiving station back to the emitter, requesting the sender to repeat the transmission of the data block. The error signal may initiate an update in the scattering and de-scattering weights or weightings in the receiving station in an effort to improve the signal and the interference ratio with respect to the traffic channel noise. The error signal can initiate an alarm that will be used for another real-time control. Or, the error signal can be registered for the compilation of a longer term report of the quality of the traffic channel. The last five steps in the flow chart of Figure 7 show the base station as the receiver. In Step 750, the Base Station performs the spectral and spatial de-dispersion of the tone of the CRC link control channel and the tones of the data block. Then, in Step 760, the Base Station performs the lattice decoding of the decoupling CRC link control channel tone and the data block tones. Then in Step 770, the Base Station generates a new CRC value on the data block and uses the block number to select the corresponding CRC vector received from the link control channel. Then, in Step 780, the Base Station compares the new CRC value calculated on the received data block with the CRC vector received from the link control channel. Then in Step 790, the Base Station generates an error signal if the new CRC does not compare to the received CRC. Figure 5 is an architectural diagram of the base station Z as an emitter and Figure 6 is an architectural diagram of the remote station X as a receiver. Figure 8 is a flow diagram showing the base station as the emitter and the remote station as the receiver. These three Figures illustrate a communication direction opposite to that shown in Figures 2, 3, and 7. The same principle of the invention applies to Figures 5, 6, and 8 as the principles described for Figures 2, 3, and 7. Figure 5 is an architectural diagram of the base station as an emitter. The PSTN inputs the data to the base station Z. The data is sent to the vector forming separator 502 and also to the cyclic redundancy code generator 504. The data vectors are output from the separator 502 to the lattice encoder 506. The data vectors are in the form of a data message formed by the concatenation of a 64-K bit data block with its block number assigned in series. The LCC vectors output from the CRC generator 504 to the lattice encoder 506 are in the form of an error detection message formed by the concatenation of the CRC value with the block number. The lattice-encoded data vectors and the LCC vectors are then output to the spectral and spatial dispersion processor 508. The resulting data tones and the LCC tones are then output from the processor 508 to the transmitter 210 for the transmission to the remote station. The first four steps in the flow chart 800 of Figure 8 show the steps in the base station Z when it is the emitter. The steps in the transmission method from a base station to a remote station are the first for the Base Station in step 810 to generate a CRC value on the data block, to assign a data block number to the CRC value , and to concatenate the CRC value and the block number in an error message which is entered as a vector to the link control channel (LCC). Then in step 820, the Base Station performs the lattice encoding of the CRC link control channel vector and the data block vectors. Then in Step 830, the Base Station performs the spectral dispersion of the control channel vector of the CRC link encoded by lattice and the vectors of the data block. Then in Step 840, the Base Station transmits the tone of the CRC link control channel and the tones of the data block to the remote station. Figure 6 is an architectural diagram of the remote station X as a receiver. The data tones and the LCC tones are received on the X antenna of the remote station. The receiver 610 passes the tones of the data and the LCC tones to the spectral de-scattering processor 612. The de-scattering signals are then output from the processor 612 to the lattice decoder 614. The data vectors 400, 400 'and 400"of Figure 4 are then output to the disassembly separator of vector 616, shown in greater detail in Figure 4. The LCC vectors 402, 402 'and 402" are output to the CRC 620 comparison processor, shown in more detail in Figure 4. Alice and Bob's data are output from separator 616 to Alice and up to Bob. The data for Alice and Bob are also input to the CRC generator 618. The CRC generator 618 calculates a new CRC value for each 64K bit data block and outputs the new CRC value and the block number to the divider 406 of the CRC 620 comparison processor. Figure 4 is a more detailed architectural diagram of the disassembly of the vector and the comparison logic of the CRC at a receiving station. The receiving station separates in the comparison processor 620 the error detection messages that it receives from the link control channel, so that they are accessible by their block numbers N, N + l, N + 2, etc. . When the receiving station receives a data message on the traffic channel, it performs a CRC calculation on the data block in the message with the CRC generator 618 to obtain a new resulting CRC value. The resulting new CRC value is separated in the separator 406 at the receiving station with the block number so that it is accessible by its block number. Then, when both the received error message and the new CRC value are both available, they are compared by the selector 404 by their common block number. The CRC value received in the error detection message 402 is compared to the new CRC calculated from the received data block 400 by means of the comparator 408. If the comparison determines that there is a difference in the values, then an error signal is generated by the generator 622. The error signal may be processed and used in various ways by the error processor 630. The error signal may initiate a negative acknowledgment signal to be sent from the receiving station back to the transmitter, requesting the sender to repeat the transmission of the data block. The error signal may initiate an update in the dispersion and de-dispersion weights or weights in the receiving station in an effort to improve the signal and the interference-to-noise ratio of the traffic channel. The error signal can initiate an alarm that will be used for the other real-time control. Or, the error signal can be registered for the compilation of a longer term report of the quality of the traffic channel. The last five steps in the flow chart of Figure 8 show the remote station as the receiver. In Step 850, the Remote Station performs the spectral and spatial de-dispersion of the control channel tone of the CRC link and the data block tones. Then, in Step 860, the Remote Station performs decoding of the lattice of the decoupling CRC link control channel tone and the data block tones. Then in Step 870, the Remote Station generates a new CRC value on the data block and uses the block number to select the corresponding CRC vector received from the link control channel. Then in Step 880, the Remote Station compares the new CRC value calculated on the received data block with the CRC vector received from the link control channel. Then at Step 690, the Remote Station generates an error signal if the new CRC does not compare with the received CRC. Although the preferred embodiments of the invention have been described in detail above, it will be apparent to those of ordinary skill in the art that obvious modifications to the invention can be made without departing from their spirit or essence. Accordingly, the foregoing description should be taken as illustrative and not as restrictive, and the scope of the invention should be determined in view of the following claims.
It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following

Claims (36)

1. A highly efficient communications method with respect to the width of the band, characterized in that it comprises the steps of: receiving in a base station a dispersion signal comprising a traffic signal of the input data, dispersed over a plurality of frequencies of discrete traffic and a signal for detecting the input errors, scattered over a plurality of link control frequencies; adaptively despread the signals received at the base station using weights or de-dispersion weights; calculate an error value for the data traffic signal; compare the error value with the error detection signal; generating an error response signal at the base station in response to the error value without comparison with the error detection signal.
2. The highly efficient bandwidth communications method according to claim 1, characterized in that the base station is part of a wireless discrete multi-tone extended spectrum communication system.
3. The method of highly efficient communications in the width of the band according to claim 1, characterized in that the error detection signal is a checksum resulting from the operation of a polynomial generator on the data block.
4. The highly efficient communication method in the width of the band according to claim 1, characterized in that the error detection signal is a cyclic redundancy code.
5. In addition, it comprises: the data traffic signal that includes a block number and the error detection signal that includes the same block number; prior to the comparison step, separating the error value from the data traffic signal and separating the error detection signal; The step of the comparison further includes the step of matching the block number of the error detection signal with the block number of the data traffic signal.
6. The highly efficient communication method in the width of the band according to claim 1, characterized in that it also comprises: initiating a negative recognition signal that is going to be sent from the base station to the transmitter, requesting the transmitter to repeat the transmission of the block of the data, in response to the error response signal.
7. The highly efficient method of communications in the width of the band according to claim 1, characterized in that it also comprises: initiating an update in the weights or weights of dispersion and de-dispersion in the receiving station in an effort to improve the signal and the interference ratio with respect to the noise of a traffic channel, in response to the error response signal.
8. The method of communications is highly efficient in the width of the band according to claim 1, characterized in that it also comprises: initiating an alarm that is going to be used for real time control, in response to the error response signal.
9. The method of highly efficient communications in the width of the band according to claim 1, characterized in that it also comprises: registering the error signal for the compilation of a longer term report of a traffic channel quality, in response to the error response signal.
10. A highly efficient communication method in the width of the band, characterized in that it comprises the steps of: receiving in a base station a first dispersion signal comprising an input data traffic signal having a block portion of the data and a portion of the block number, scattered over a plurality of discrete traffic frequencies; receiving at the base station a second dispersion signal comprising an input error detection signal having an error detection portion and the block number portion, scattered over a plurality of link control frequencies; Dispersing adaptively the first dispersion signal received at the base station using weights or de-dispersion weights, recovering the block portion of the data and a portion of the block number; calculating an error value for the block portion of the data in the base station; Dispersing adaptively the second scattering signal received at the base station using de-dispersion weights, recovering the error detection portion and the block number portion; compare the value of the error with the detection portion of the error in the base station; generating an error response signal at the base station in response to the error value without comparison with the error detection portion.
11. The highly efficient bandwidth communications method according to claim 10, characterized in that the base station is a part of a wireless discrete, multi-tone extended spectrum communication system.
12. The method of highly efficient communications in the width of the band according to claim 10, characterized in that the error detection signal is a checksum resulting from the operation of a polynomial generator on the data block.
13. The highly efficient communication method in the width of the band according to claim 10, characterized in that the error detection signal is a cyclic redundancy code.
14. The highly efficient method of communication in the width of the band according to claim 10, characterized in that it further comprises: prior to the comparison step, separating the value of the error from the signal of the data traffic and separating the detection signal from the mistakes; The comparison step further includes the step of comparing the block number of the error detection signal with the block number of the data traffic signal.
15. The method of highly efficient communications in the width of the band according to claim 10, characterized in that it also comprises: initiating a negative recognition signal that is going to be sent from the base station to the transmitter, requesting the transmitter to repeat the transmission of the data block, in response to the error response signal.
16. The method of highly efficient communications in the width of the band according to claim 10, characterized in that it also comprises: initiating an update in the weights or weights of dispersion and de-dispersion in the receiving station in an effort to improve the signal and the interference ratio with respect to the noise of a traffic channel, in response to the error response signal.
17. It also comprises: initiating an alarm to be used for real time control, in response to the error response signal.
18. The highly efficient method of communications in the width of the band according to claim 10, characterized in that it also comprises: recording the error signal for the compilation of a longer term report of a traffic channel quality, in response to the error response signal.
19. A highly efficient method of communications in the width of the band, characterized in that it comprises: means for receiving in a base station a dispersion signal comprising a traffic signal of the input data scattered over a plurality of discrete traffic frequencies and a detection signal of the input error scattered over a plurality of link control frequencies; means for adaptively descrambling the signals received at the base station using the dispersion weights or weights; means for calculating an error value for the data traffic signal; means for comparing the value of the error with the error detection signal; means for generating an error response signal in the base station in response to the error value without comparing with the error detection signal.
20. The highly efficient bandwidth communications system according to claim 19, characterized in that the base station is part of a wireless discrete multiple-tone extended spectrum communication system.
21. The highly efficient bandwidth communication system according to claim 19, characterized in that the error detection signal is a checksum resulting from the operation of a polynomial generator on the data block.
22. The highly efficient communication system in the width of the band according to claim 19, characterized in that the signal. Error detection is a cyclic redundancy code.
23. The highly efficient bandwidth communication system according to claim 19, characterized in that it further comprises: the data traffic signal includes a block number and the error detection signal includes the same block number; means for damping the error value for the data traffic signal and damping the error detection signal; and means for comparing the block number of the error detection signal with the block number of the data traffic signal.
24. The highly efficient communication system in the width of the band according to claim 19, characterized in that it also comprises: means for initiating a negative acknowledgment signal that is going to be sent from the base station to the transmitter, requesting the sender to repeat the transmission of the data block, in response to the error response signal.
25. The highly efficient communications system in the width of the band according to claim 19, characterized in that it further comprises: means for initiating an update in the weights or weights of dispersion and de-dispersion in the receiving station in an effort to improve the signal and the interference ratio with respect to the noise of a traffic channel, in response to the error response means for generating an error response signal in the base station in response to the error value without comparison with the detection portion of the error. error.
26. The communication system is highly efficient in the width of the band according to claim 19, characterized in that it also comprises: means for initiating an alarm that is to be used for real time control, in response to the error response signal .
27. The highly efficient bandwidth communication system according to claim 19, characterized in that it further comprises: means for recording the error signal for compiling a long-term report of a traffic channel quality, in response to the error response signal.
28. A highly efficient communication system in the width of the band, characterized in that it comprises: means for receiving in a base station a first dispersion signal comprising a traffic signal of the input data having a portion of the data block and a portion of the block number, dispersed over a plurality of discrete traffic frequencies; means for receiving at the base station a second dispersion signal comprising an input errror detection signal having an error detection portion and the block number portion, scattered over a plurality of link control frequencies; means to adaptively disperse the first scatter signal received at the base station using the de-scattering weights or weights, recover the block portion of the data and a portion of the block number; means for calculating an error value for the block portion of the data in the base station; means for adaptively desdispersing the dispersion signal received at the base station using weights or de-dispersion weights, recovering the error detecting portion and the block number portion; means for comparing the error value with the detection portion of the error in the base station, and means for generating an error response signal in the base station in response to the error value without comparison with the error detection portion.
29. The highly efficient bandwidth communications system according to claim 28, characterized in that the base station is part of a wireless discrete multi-tone extended spectrum communication system.
30. The highly efficient bandwidth communication system according to claim 28, characterized in that the error detection signal is a checksum resulting from the operation of a polynomial generator on the data block.
31. The highly efficient communications system in the width of the band according to claim 28, characterized in that the error detection signal is a cyclic redundancy code.
32. The communication system is highly efficient in the width of the band according to claim 28, characterized in that it further comprises: means for separating the error value from the data traffic signal and separating the error detection signal; and means for comparing the block number of the error detection signal with the block number of the data traffic signal.
33. The highly efficient communication system in the width of the band according to claim 28, characterized in that it also comprises: means for initiating a negative recognition signal that is going to be sent from the base station to the transmitter, requesting the transmitter to repeat the transmission of the data block, in response to the error response signal.
34. The highly efficient communication system in the width of the band according to claim 28, characterized in that it further comprises: means for initiating an update in the weights or weights of dispersion and de-dispersion in the receiving station in an effort to improve the signal and the interference ratio with respect to the noise of a traffic channel, in response to the error response signal.
35. The communication system is highly efficient in the width of the band according to claim 28, characterized in that it also comprises: means for initiating an alarm that is to be used for real time control, in response to the error response signal .
36. The highly efficient bandwidth communications system according to claim 28, characterized in that it further comprises: means for recording the error signal for the compilation of a longer term report of a traffic channel quality, in response to the error response signal. SUMMARY OF THE INVENTION A new method makes more efficient use of scarce spectral bandwidth in a wireless discrete multi-tone extended spectrum communications system. Each remote station and each base station in the network prepare a field for detecting errors, such as a cyclic redundancy code (CRC), on each block of data that is to be transmitted over the traffic channels. The sending station prepares an error detection message for transmission over the link control channel of the network. The sending station prepares the error detection message by forming a vector of the link control channel that will be dispersed using the discrete multiple tone spread spectrum (DMT-SS) protocol to distribute the message of the data over a plurality of discrete tone frequencies, forming a dispersion signal for the link control channel. A link control channel is associated with the communication session using the traffic channels. The instant of transmission of the error detection message is allowed to be different from the instant of transmission of the data message. This allows error detection messages to be transmitted when the capacity is available over the link control channel. The receiving station separates the messages from the detection of the error that it receives from the link control channel, so that they are accessible by their block numbers. When the receiving station receives a data message about the traffic channel, it performs a CRC calculation on the block of data in the message to obtain a new CRC value resulting. The new CRC value is also separated at the receiving station with the block number so that it is accessible by its block number. Then, when both the received error message and the new CRC value are both available at the receiving station, they are compared by their common block number. The CRC value received in the error detection message is compared to the new calculated CRC of the received data block. If the comparison determines that there is a directness in the values, then an error signal is generated.
MXPA/A/1999/007730A 1997-02-24 1999-08-20 Out of channel cyclic redundancy code method for a discrete multitone spread spectrum communications system MXPA99007730A (en)

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