Abstract: A system, method and apparatus includes a transmitter that has an encoder and baseband modulator that encodes and modulates a sequence of payload data symbols as a signal constellation to be communicated. An amble generator and baseband modulator generates amble symbols as a known sequence of M symbol times in length every N symbol times. A multiplexer multiplexes the data and amble symbols together to form a communications signal that is transmitted over a communications channel.

Abstract: Embodiments of the invention provide method and apparatus for generating a structure in an orthogonal frequency division multiplexing OFDM communication system having a transmitter with one or more transmitting antennas. The method includes composing a frame with a time domain and a frequency domain. The frame has a transmission time interval in the time domain and occupies a bandwidth in the frequency domain. The transmission time interval has multiple orthogonal frequency division multiplexing symbols. A pilot signal is located from a transmitting antenna into two non-consecutive orthogonal frequency division multiplexing symbols of the frame.

Abstract: A method for verifying interoperability of an implementation of a communication standard includes monitoring a symbol comprising a set of subcarrier symbols in a communication stream, in which some of the subcarrier symbols of the symbol are generated from pilot symbols, transmitted on subcarriers in accordance with the standard. For a given implementation and a given symbol, it is known which subcarriers will be pilot symbols, and what their pilot symbol values will be. A communication stream, generated by an implementation that is interoperable with the standard, will contain expected pilot information. Using the implementation to be verified, a communication stream is generated, containing pilot information. The generated pilot information is compared with the expected pilot information, and interoperability is determined based on the result of the comparing.

Abstract: An orthogonal frequency division multiplexing (OFDM) transmission apparatus and method generate a transmission sequence including first data, second data, and known signals such that more known signals are allocated to the first data than to the second data within the transmission sequence. The transmission sequence is OFDM multiplexed into a sequence of OFDM signals and transmitted. A receiver of the OFDM signal sequence uses the known signals for estimating transmission paths of the communicated OFDM signals and improving the reception of the data to which they are allocated.

Abstract: Angle estimation for modulated signal. A novel compensation technique is presented by which angle estimation may be performed for a modulated signal. More specifically, the angle between a constellation corresponding to a received signal and a constellation corresponding to a received signal may be very efficiently estimated using any one of the possible embodiments corresponding to various aspects of the invention. After this angle has been estimated, the received signal or the expected constellation may be rotated (or de-rotated) to compensate for this angular difference. In doing so, better estimates of the information bits that are demodulated and decoded from the received signal may be made.

Abstract: An object of the present invention is to provide a radio quality estimation system, a base station, a mobile station, and a radio quality estimation method whereby, regardless of influence of fading, a radio quality of a predetermined measurement period is more accurately estimated. An interference power calculator calculates an interference-signal power of each of local estimation intervals which are parts of the predetermined estimation interval. An SIR calculator calculates an SIR of the predetermined estimation interval based on the interference-signal powers calculated by the interference power calculator.

Abstract: A hardware apparatus (10) for conditioning pilot symbols for channel estimation in a mobile radio comprises a time-division multiplexed low-pass filter unit for filtering the received pilot symbols. The time-division multiplexed low-pass filter unit comprises, between its input and its output, a feedback path which can be switched in and which can be used to implement a plurality of filter stages in a time-division multiplexed arrangement.

Abstract: A wireless communication method includes generating and transmitting an OFDM signal containing a first OFDM symbol possessing a first transmitting pilot signal and a second transmitting pilot signal respectively allocated to a first subcarrier and a second subcarrier being symmetric with respect to a center frequency on a frequency axis, and a second OFDM symbol possessing a third transmitting pilot signal and a fourth transmitting pilot signal respectively allocated to the first subcarrier and the second subcarrier, wherein a difference between a product of a first transmitting pilot signal and a complex conjugate of a fourth transmitting pilot signal and a product of a third transmitting pilot signal and a complex conjugate of a second transmitting pilot signal is non-zero.

Abstract: Systems and techniques are disclosed detecting an embedded signal which includes producing a plurality of first correlated values from a portion of the first signal and a second signal, transforming the first correlation values into a plurality of second correlation values related to a frequency content of the first correlation values, and searching for the embedded signal by evaluating the second correlation values. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Abstract: The position of a specific pattern such as a known symbol in a signal such as an OFDM signal is estimated with high accuracy. An effective symbol extraction section extracts a known symbol (preamble) as an effective symbol from a signal to be measured according to an approximate position of the known symbol. A mixer determines the product of the frequency spectrum of the extracted effective symbol by the result of the conversion performed by a complex conjugate conversion section from the frequency spectrum of the known symbol into the conjugate complex. A phase shift amount measuring section measures the phase shift amount ?? of the product determined by the mixer. A precision pattern position measuring section measures the difference between the position of the known symbol and its approximate position on the basis of the phase shift amount.

Abstract: The present invention provides an audio data sync format detecting circuit that can minimize both the hardware configuration software processing, and furthermore, has a large flexibility with respect to unknown formats. Audio data is written in sequence into a data register, where the audio data are units having a predetermined number of bits. Samples of the format that is the object of detection are written in sequence into a register. A comparator compares the data in the sample register and the data in the data register. A control circuit receives hit signals and outputs an interrupt signal to the controller, and the controller writes in sequence samples of the format that is the object of detection into the register each time an interrupt signal is received. When hit signal is continuously output a predetermined number of times, a match detection circuit outputs a format match signal.

Abstract: The invention relates to data communications, more particularly to a protocol encapsulation technique which captures the time between frames at a transmitting site for comparison with an idle counter at a receiving site. At the originating site, the time between successive frames in the native protocol is encoded in an interframe time field associated with each respective frame, before the time encoded frame is mapped into the protocol associated with the transport medium. At the destination site, the framing associated with the transport medium is removed to reveal the interframe time field. The value contained in this field is compared with the value of an idle counter running at the native protocol rate. When the idle count is greater than or equal to the encoded inter-frame time, the data contained in the frame is then delivered to the client.

Abstract: In an OFDM system the same Walsh code is used at the same time for a plurality of transmitters. The multiple transmitters can be from the same, or different devices (e.g., different base stations on the downlink, different terminals on the uplink). Each subcarrier/antenna combination will share a similar pilot Walsh code, except for the fact that the scrambled spread pilot signals will be phase shifted on some subcarriers of some antennas, based on the subcarrier/antenna combination.

Abstract: A method and apparatus for pilot signal transmission is disclosed herein. In particular, a pilot transmission scheme is utilized where pilot sub-carrier bandwidth differs from data sub-carrier bandwidth. Because some user's data sub-carriers will no longer have the user's pilot sub-carriers adjacent to them, the set, or pattern of sub-carriers used by the pilot blocks changes at least once in a burst. Changing the pilot block pattern (the set of occupied pilot block sub-carriers) at least once in the burst serves to increase the frequency proximity of occupied data sub-carriers to occupied pilot sub-carriers in the burst.

Abstract: A method of transmitting pilot signals in a system which performs communication using two or more earners comprises transmitting first pilots and second pilots from at least one user equipment to a base station, the first and second pilots, which are transmitted from the at least one user equipment, being multiplexed by code division multiplexing, and the first and second pilots, which are transmitted from a specific user equipment, having different transmission powers, and transmitting data from the at least one user equipment to the base station depending on the first pilots and the second pilots. Since many UEs can transmit CQ pilots, exact channel estimation can be performed and thus communication efficiency can be improved.

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

Abstract: In a wireless communication method and system, a data/pilot constellation is modulated and generated based on input information bits. Channel estimation (CE) sequence in frequency-domain is off-line generated. The frequency-domain channel estimation sequence is transformed into a time-domain channel estimation sequence by ideal IFFT to avoid IFFT (Inverse Fast Fourier Transform) impact to EVM (Error Vector Magnitude) performance. Off-line resealing the time-domain CE sequence, multiplied by a rescaling coefficient, in time-domain improves EVM performance. Further, the time-domain channel estimation sequence is off-line quantized.

Abstract: Base stations transmit strip signals using strip signal segments and self supporting modulation scheme techniques facilitating rapid channel estimate. A strip segment occupies one OFDM symbol time interval and uses a set of downlink tones; some, e.g., half, of the tones are left unused facilitating SIR measurement. The strip segments are advantageously timed to correspond to uplink access intervals in which connected wireless terminals do not typically transmit uplink signals. Connected wireless terminals including: multiple antennas used in combination, an antenna duplex module, single RF receiver chain and single RF transmitter chain, switch antenna coefficient combinations based on strip signal segment timing. The wireless terminal determines an independent downlink channel quality measurement, e.g., SNR and/or SIR for each strip signal segment and for on-going non-strip signaling.

Abstract: The invention provides a multicarrier system constructed on a time-frequency lattice defined comprising frames having MxN symbols distributed over M subcarriers each of which is divided into N specific symbol times. Each frame comprises P pilot symbols distributed time-wise and frequency-wise so as to cover the frame in a meshed structure, so that, in particular, some at least of the M subcarriers contain no pilot symbol and/or that no pilot symbol should be transmitted to some at least of the N symbol times. The invention also relates to a method for tracking a transmission channel using such a signal, and a device for implementing the method.

Abstract: There is provided a data communication system that performs power line communication having satisfactory communication quality by disposing data in channels where notches or noises do not exist in a distributed manner.

Abstract: To allow a receiving entity to derive a longer channel estimate while limiting overhead, a transmitting entity transmits a pilot on different groups of subbands in different time intervals. N subbands in the system are arranged into M non-overlapping groups. Each group includes P=N/M subbands that are uniformly distributed across the N subbands. The transmitting entity transmits the pilot on a different subband group in each time interval, and selects all M subband groups in M time intervals based on a pilot staggering pattern. The receiving entity derives (1) an initial impulse response estimate with P channel taps based on the pilot received on one subband group and (2) two longer impulse response estimates with different lengths used for data detection and time tracking. Each longer impulse response estimate may be derived by filtering initial impulse response estimates for a sufficient number of subband groups using a time-domain filter.

Abstract: Carrier frequency selection and handoff initiation methods in wireless communications systems employing multiple carrier frequencies are described. Although the receiver is tuned to a single band, based on the relative energy of one or more beacon signal components corresponding to the currently used carrier and one or more beacon signal components corresponding to an alternative carrier, a carrier selection and a handoff determination is made. Mobile nodes can use a single RF chain with a controllable RF filter to receive and process a signal within a first selected carrier band including components from different transmitters, e.g., a first signal component identified with the first currently selected band and a second signal component identified with a second alternative band. The signal components, e.g., beacon signal components from different transmitters may be obtained from a signal which corresponds to multiple symbol transmission time periods.

Abstract: In a wireless local area network (WLAN) that includes high-throughput communication devices with multiple antennas and legacy communication devices with single antennas, training tones are transmitted over a plurality of spatial channels during a first portion of an orthogonal frequency division multiplexed (OFDM) packet-training preamble. The training tones are interspersed among subcarrier frequencies of the spatial channels. The training tones are retransmitted during a second portion of the packet-training preamble. The training tones are shifted among the subcarrier frequencies of the spatial channels during the retransmission allowing a high-throughput receiving station to perform a channel estimation on different subcarrier frequencies of the spatial channels. The legacy communication devices may receive and process the training tones and may set their network allocation vector to refrain from communicating during a subsequent interval.

Abstract: A system, method and apparatus includes a transmitter that has an encoder and baseband modulator that encodes and modulates a sequence of payload data symbols as a signal constellation to be communicated. An amble generator and baseband modulator generates amble symbols as a known sequence of M symbol times in length every N symbol times. A multiplexer multiplexes the data and amble symbols together to form a communications signal that is transmitted over a communications channel.

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

Abstract: An apparatus and method for transmitting/receiving a pilot pattern set to distinguish a base station in an FDM communication system. The method divides a total frequency bandwidth into at least two sub-bandwidths including a plurality of sub-carriers in an OFDMA (Orthogonal Frequency Division Multiple Access) mobile communication system, configures a single frame cell (FC) using one sub-bandwidth from among the sub-bandwidths and a plurality of OFDM (Orthogonal Frequency Division Multiplexing) symbol intervals, and assigns a pilot signal to a time-frequency cell comprised of at least one OFDM symbol and at least one sub-carrier within the FC. The method includes the steps of spreading a pilot signal and a data signal using different orthogonal codes, synthesizing the spread pilot and data signals, and performing a CDM (Code Division Multiplexing) process; and mapping the CDM-processed pilot and data signals to a predetermined time-frequency cell in the FC.

Abstract: Equipment for transmitting a signal, the equipment comprising an antenna array (600-606) for providing three or more radiation antenna patterns. The equipment is arranged to transmit a primary common pilot signal with at most two radiation patterns and a secondary common pilot signal with at least one radiation pattern. The equipment comprises controllers (622a-622d) for adjusting the power ratio between the primary and the secondary common pilot signal and the total power of the primary and the secondary common pilot signals, and controllers (614a-614d) for adjusting the transmit power of the dedicated pilot signal, such that the power levels of the dedicated pilot signals transmitted with the same radiation patterns as the secondary common pilot signal are relatively higher than the power levels of the dedicated pilot signals transmitted with the same radiation patterns as the primary common pilots.

Abstract: Transmission scheme for the uplink of FDMA systems that improves performance in an interference-dominated system by using a pilot scheme that provides enough information so that channel estimates can be obtained for a particular user, but which at the same time makes it possible to use pilot patterns that are different in different cells so that co-channel interference is mitigated. A codeword is used to position a set of pilot symbols within a set of subcarriers wherein each subcarrier has a first pilot time slot and a second pilot time slot associated with one or more data time slots. The set of subcarriers are identified on which to transmit the composite signal and the first pilot time slots and the second pilot time slots are filled with the pilot symbols in accordance with the codeword. The composite signal is then formatted as a combination of modulated data and pilot signals.

Abstract: Systems and methodologies are described that facilitate detecting and/or identifying peers in a local area peer-to-peer network. Times (e.g., peer discovery intervals) for performance of mutual detection and identification between peers may be synchronized (e.g., based upon a signal broadcast to the peers), Further, within each partitioned peer discovery interval, a wireless terminal may select a portion of time to transmit (e.g., broadcast) short messages that may be employed by peers to detect and/identify the wireless terminal. Moreover, the remainder of the time within the partitioned peer discovery interval may be employed to listen to short messages received from peers.

Abstract: The present invention discloses a method for pilot channel tracking based on multipath channel barycenter tracking loop, comprises steps of evaluating multipath fading channel parameters, calculating the barycenter of a multipath energy window, and loop filtering and adjusting the phase of spread spectrum sequence codes. The method of the invention does not need to individually track each delay path, thereby improving the tracking performance and timing recovery stability of a spread spectrum receiver. Only a multipath channel evaluator and a multipath energy window barycenter calculating means are used to track PN signals from a plurality of signal sources, thereby reducing hardware. Thus, a novelty coherent spread spectrum receiver can be constituted by cooperating with other parts.

Abstract: A reference signal multiplexing method for multiple mobile stations includes: grouping together control signals for the multiple mobile stations; and multiplexing reference signals corresponding to the control signals by CDM over the same bandwidth as that of grouped control signals.

Abstract: For demodulating radio navigation signals (s(t)) transmitted in spread spectrum and comprising a data channel modulated by a navigation message and a pilot channel not modulated by a navigation message, the data channel and the pilot channel are combined into one multiplexing scheme so as to modulate a carrier, this method consists in applying de-spreading processing to the pilot and data channels' signals and in demodulating the de-spread data signal (rd) in order to obtain the navigation message <d(t)>, the demodulation of the de-spread data signal (rd) used to obtain the navigation message <d(t)> is performed using the carrier (rp) obtained from the dispreading processing of the pilot channel.

Abstract: In the channel quality information (CQI) coding method of the present invention, first basis sequences for generating sub-codes of 32 bits are created, and second basis sequences for generating codewords of 20 bits are created using the first basis sequences, the second basis sequence maximizing system throughput such that five information bits are coded into CQI code using the second basis sequences. Also, since HSDPA system has been designed in order to increase the system throughput, the CQI coding method of the present invention, which shows the best system throughput in the simulation, can be the optimum CQI coding scheme for HS-DPCCH.

Abstract: A method is provided for extracting a sequence of pilot symbols enabling to estimate the transfer function of a transmission channel. At least a radiocommunication device communicates through the channel with a remote station, the latter regularly delivering to the radiocommunication device a reference pattern. The structure of the reference pattern is variable, depending on at least one characteristic of the transmission channel.

Abstract: In an orthogonal frequency division multiplexing (OFDM) system, a receiver of an OFDM signal via an air interface defines training symbols to be included in the frame structure of the air interface and a post-FFT receiver algorithm that can efficiently estimate a fractional frequency offset (e.g., a frequency offset less than a single intercarrier spacing). The algorithm may be modified to estimate a large frequency offset (e.g., of more than a single intercarrier spacing) using increased hardware complexity. The algorithm does not need a correlator block in its simplest implementation. The frequency detection itself features excellent performance in a very low SNR environment. However, if noise plus timing error is present, system parameters may be designed to substantially assure good performance in low SNR.

Abstract: There is provided a method and apparatus for selecting an appropriate base station and an optimal data rate to provide a voice service and a data service based on a voice service load in a CDMA system. A base station transmits two pilot signals orthogonally spread with different orthogonal codes in association with its voice service load, and a mobile station estimates the voice service load based on a pilot power ratio.

Abstract: Method embodiments for achieving hyperframe symbol synchronization are disclosed, along with device and system embodiments for implementing such methods. In one embodiment, the method comprises: receiving a pilot signal having at least two phase states; measuring the pilot signal as a sequence of measured symbols; and determining an alignment offset upon detecting between adjacent measure symbols a phase difference greater than a predetermined threshold. The alignment offset determination may include: forming a data field of four measured symbols around the detected phase difference; searching for the position of a two-symbol window in the data field that maximizes a phase difference; and calculating the alignment offset from this position.

Abstract: By providing a interference power estimation unit obtaining the power of interference in a common pilot signal with ten symbols in one slot and outputting the power of interference as the estimate of the amount of interference in the data signal's pilot signal and a signal-to-interference power ratio calculation unit calculating a signal-to-interference power ratio (SIR) using an output of the interference power estimation unit, in a spread spectrum communication method, a correct SIR can be estimated even when the number of symbols of an individual pilot signal in the slot of the data channel is small.

Abstract: A method and apparatus for wireless transmission from a mobile unit to a base station includes multiplexing a pilot signal and a data signal, wherein the data signal operates at a data rate by splitting the data signal into a plurality of data streams; applying a pilot gain to the pilot channel, wherein the data gain and the pilot gain are a function of the data rate; and combining the plurality of data streams and the pilot signal into a subset of sub-carriers. The subset of sub-carriers are transmitted using Discrete Fourier Transform Spread OFDMA.

Abstract: A transmitter forms each subcarrier group of only frequency locations of subcarriers to which at least one pilot signal is allocated, and conducts transmission by allocating a macro-diversity signal into the subcarrier group and allocating a non-macro-diversity signal to other frequencies (outside the subcarrier group). As for the macro-diversity signal, a receiver conducts channel estimation on the basis of the pilot signal in the same subcarrier group as the macro-diversity signal. As for the non-macro-diversity signal outside the subcarrier group, the receiver conducts channel estimation on the basis of the pilot signal, and results of channel estimations of the macro-diversity signal and other non-macro-diversity signals.

Abstract: In an OFDM system the same Walsh code is used at the same time for a plurality of transmitters. The multiple transmitters can be from the same, or different devices (e.g., different base stations on the downlink, different terminals on the uplink). Each subcarrier/antenna combination will share a similar pilot Walsh code, except for the fact that the scrambled spread pilot signals will be phase shifted on some subcarriers of some antennas, based on the subcarrier/antenna combination.

Abstract: A cell search apparatus and method in a W-CDMA mobile communication system. The cell search apparatus and method performs a first cell search step, a second cell search step, and a third cell search step using a slot count value and a lower count value, counted by an index counter after being initialized upon power up of a UE (User Equipment), thereby determining a scrambling code for a Node B. Further, the cell search apparatus and method manages neighboring Node Bs by performing a multipath search.

Abstract: A user equipment (UE) located in a soft handover region transmits channel quality indicator (CQI) information bits for informing a Node B of quality of a downlink channel through a CQI field and a high speed pilot (HS-Pilot) field constituting a subframe of an uplink secondary dedicated physical control channel (DPCCH) in a code division multiple access (CDMA) communication system. The UE outputs a codeword of length 20 by coding the CQI information bits with a code of length 20, which is used when a high speed downlink packet access (HSDPA) service is not supported, and permutes 15 coded bits coded by the same code, as a code of length 15, which is used when the HSDPA service is supported, among 20 coded bits constituting the codeword, thereby locating the 15 coded bits in the CQI field, and permutes the 5 remaining coded bits to be located in the HS-Pilot field.

Abstract: Systems and methods for correcting phase ambiguity in a total pilot phase value are presented. Examples include comparing and correcting total pilot phase values having different pilot frequencies within the same sampling interval, such as the same data symbol. Another example includes correcting a total pilot phase value for one sampling interval and corresponding to one pilot frequency using nonlinear filtering of values of the total pilot phase for prior sampling intervals at the same pilot frequency.

Abstract: Symbol 102 that is spread with the only short spreading code and inserted in synchronism with a long spreading code is specified by detecting the correlation with only the short spreading code. Next, another short spreading code indicative of a timing of reverse and forward link switching is specified, where the short spreading code is multiplexed at the same position as that of the detected symbol. The detection of the symbols spread with only these spreading codes enables to acquire synchronization of the long spreading code, synchronization of switching of reverse and forward links, and synchronization of a transmission frame. It is thereby possible to reduce synchronization acquisition time for the long spreading and an easy planning of base station locations without decreasing the frequency utilization efficiency.

Abstract: In a wireless communication system a method for combination transmission of packet data and low delay data. In one embodiment a parallel signaling channel provides a message to receivers indicating a target recipient of packet data. The message also identifies the transmission channels used for packet data transmissions. Each receiver may then selectively decode only packets where the message identifies the receiver as a target recipient. The data packets stored in a buffer are ignored if the target recipient is another mobile unit. In one embodiment, the message is sent concurrently with the data packet on a parallel channel. In one embodiment, the message is punctured into the high rate packet data transmission.

Abstract: The invention is a method for limiting the peak transmit power in a CDMA communication system including the steps transmitting a first communication signal having a first high transmit power region and transmitting a second communication signal having a second high transmit power region. One of the first and second communication signals is time offset to prevent the first and second high transmit power regions from occurring simultaneously. Time shifting only a portion of one of the first and second communications signals is also taught. The first and second communication signals can also include respective first and second low transmit power regions. The time offset can be selected to align one of the first and second high transmit power regions with one of the first and second low transmit power regions.

Abstract: An optical communication system for optically transmitting transmission data from a transmitting station to a transmitting device includes an adder for adding an intermediate frequency subcarrier signal modulated with data to be transmitted to a pilot carrier signal as a sinusoidal wave, and an electro-optical converter for electro-optically converting the above sum signal to an optical signal by directly modulating a semiconductor laser element having a resonant frequency fr in accordance with the sum signal and transmitting the signal to an optical fiber for a down link. The frequency fIF of the intermediate frequency subcarrier signal and the frequency fLO of the pilot carrier signal satisfy fLO?fIF?1[GHz], 2×fIF<fLO<(?)×fr, fIF<1[GHz], and 2 [GHz]<fLO.

Abstract: A system and method selectively establishes data communications, such as XDSL services, between data devices and a network switch. Status of the data devices are monitored and active data devices are connected to a data branch for data communications. Data devices which are inactive may remain connected to the data branch, if available, or may be switched to a pilot branch. While disconnected from the pilot branch, the system may detect a signal from the data device indicating that the device is going active. If pilot signals are being used, the pilot signals between a data device and the network switch are monitored to determine when the data device is going active. Once detected, the data device is connected to the data branch. Alternately, if pilot signals are not being used, the system monitors the connection with the data device for any signals, such as a wake-up signal, which indicates that the data device is going active.

Abstract: There is provided a method and apparatus for selecting an appropriate base station and an optimal data rate to provide a voice service and a data service based on a voice service load in a CDMA system. A base station transmits two pilot signals orthogonally spread with different orthogonal codes in association with its voice service load, and a mobile station estimates the voice service load based on a pilot power ratio.