ES2614111T3 - Mobile unit and method implanted in a mobile unit - Google Patents

Abstract

A mobile unit (42) comprising: means for transmitting, to a base station, signals (165, 170) that have different formats in terms of different power levels in time intervals where the mobile unit is not transmitting data, means for transmitting signals having different formats comprising means for demanding, in at least one of the different formats (170), for the mobile unit, resources for transmitting data; at least two of the different formats (170) being associated with different power levels; means for applying a first power level for a non-demand state and means for applying a second power level for a demand state; means for receiving information indicating the resources that allow data to be transmitted, in response to the demand made by the mobile unit (42), for the resources that allow data to be transmitted; means for assigning an orthogonal sequence and means for deriving the signals transmitted from the orthogonal sequence; characterized by means for transmitting signals for the non-demand state and signals for the demand state in a channel of mutually exclusive codes in time intervals when a pulse signal is at a logical zero level.

Description

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DESCRIPTION

Mobile unit and method implemented in a mobile unit BACKGROUND OF THE INVENTION

The increasing use of wireless telephones and personal computers has led to a corresponding increase in the demand for advanced telecommunications services that were considered once practical only for specialized applications. In the 1980s, wired vocal communications became widely available through mobile phone networks. These services were considered, first of all, as being the exclusive domain of businessmen due to the high subscription costs provided. The same was also true for access to distant distributed computer networks, where, until very recently, only businessmen and large institutions could access the necessary computers and wired access equipment.

As a consequence of the wide availability of new affordable technologies, users in general now increasingly want not only to have wired access to networks such as private Internet and Intranet, but also wireless access. The wireless technology is particularly useful for users of portable computers, laptops, portable personal digital assistants and similar devices that prefer access to such networks without connecting to a telephone line.

There is still no satisfactory solution widely available to provide high-speed, low-cost access to the Internet, private Intranets and other networks using existing wireless infrastructure. The foregoing is very likely a so-called computer artifact of several unfortunate circumstances. First, the typical way of providing a high-speed data service in the business environment through a wired network is not easily adaptable to the voice quality service available in most of the offices or places of residence. By way of example, said standard high-speed data services do not necessarily provide for efficient transmission through standard mobile wireless handsets since the wireless networks were originally designed only to provide voice services. Consequently, current digital wireless communications systems are optimized for voice transmissions, although some systems such as CDMA provide some measure of asymmetric behavior for the admission of data transmissions. As an example, the data rate specified by the Telecommunication Industry Association (TIA) for IS-95 in the traffic channel without return path is adjustable in increments from 1.2 kbps to 9.6 kbps for the so-called set asf of rates 1 and rate increases from 1.8 kbps to 14.4 kbps for the so-called set of frames 2. In the link traffic channel with no return path, however, the data rate is set at 4.8 kbps.

In the best case, existing wireless systems usually provide, therefore, a radio channel that can support transfers of maximum data rates of 14.4 kilobits per second (kbps) through a link address without a return path . Said low data rate channel does not lend itself directly to transmitting data at rates of 28.8 or even 56.6 kbps that are now normally available using non-high-cost cabling modems, nor to mention even higher rates such as 128 kbps. which are available with the Digital Services Integrated Services (ISDN) type equipment. Data rates at these levels quickly become the minimum acceptable rates for activities such as web page exploitation.

Although wired networks are known at the time of the initial development of cellular systems, for the most part, there is no provision for such wireless systems to provide data services of the ISDN or ADSL type at a higher speed with respect to topology of cellular networks

In most wireless systems, there are many more potential users than in radio channel resources. Some type of demand-based multiple access system is required accordingly.

If multiple access is provided by a traditional Frequency Division Multiple Access (FDMA) system, using an analog modulation in a group of radio frequency carrier signals, or by systems that allow the shared use of a radio carrier frequency using the Multiple Access by Time Division (TDMA) or Multiple Access by Code Division (CDMA) system, the nature of the radio spectrum is such that it is intended to be shared. This situation is quite different from the traditional environment that supports data transmission where wired support is relatively low cost and is not usually intended to be shared.

Other factors to consider in the design of a wireless system are the characteristics of the data itself. As an example, it can be considered that access to web pages is usually burst-oriented, with requirements for the transmission of asymmetric data rates in a reverse and direct direction. In a common application, a user of a remote client computer first specifies the address of a web page to a browser program. The browser program then sends the web page address data, which is usually 100 bytes or less in length, across the network to a server computer. The server computer responds,

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Then, with the content of the website demanded, it can include any value from 10 kilobytes to several megabytes of text, image, audio or even video data. Then, the user can spend several seconds or even several minutes reading the content of the page before downloading another web page.

In an office environment, the nature of the computer work habits of the majority of employees is usually to check a few websites and then do everything else for an extended period of time, such as accessing locally stored data or even terminal the use of the computer as a whole. Therefore, even if such users can remain connected to the private Internet or Intranet continuously throughout the entire day, the actual use of the high-speed data link is usually quite sporadic.

If wireless data transfer services, which support Internet connectivity are to coexist with wireless voice communication, it becomes increasingly important to optimize the use of available resources in wireless CDMA systems. The frequency of reuse and dynamic allocation of traffic channels solve some aspects of increasing the efficiency of high-performance wireless CDMA communications systems, but there is still a need for a more efficient use of available resources.

EP-0760564-A2 describes an access protocol in a radiocommunication system where a plurality of mobile stations use OFDM for an uplink between the mobile station and a base station. The mobile station transmits a random access sequence in a random access channel and the sequence is repeated in a cyclic manner. The mobile station checks an AGCH access concession channel to determine if access has been granted and if the mobile station has not been granted access, the random access sequence is retransmitted to a higher power.

SUMMARY OF THE INVENTION

The invention is defined by the appended claims.

One way to obtain a more efficient use of available resources is to ensure that resources are allocated in an error-free manner. As an example, a base station should not assign traffic channels to a mobile unit when a demand for traffic channels has not been made. Similarly, the base station must assign traffic channels to a mobile unit when a demand has been made. Said demand is made by the mobile unit when the mobile unit is used by a user to send traffic data to a remote network node.

In one application, a transmission of a marker in a time interval through a channel indicates a demand by the corresponding mobile unit to be active. That is, the transmission of a brand in an assigned time interval indicates that the mobile unit is demanding that reverse link traffic channels be assigned to the user to transmit a payload of data from the mobile unit to the base station. The above assumes that the mobile unit is currently in reserve mode. As an alternative, a mobile unit transmits a mark through a second channel of the reverse link channel pair to indicate that the mobile unit is not demanding that it be placed in active mode. As an example, the mobile unit does not wish to transmit data through a reverse link channel. Instead, the mobile unit demands to remain inactive but synchronized with the base station so that the mobile unit can immediately go back to the active state at any time.

In either case, the present invention improves the performance to detect a signal that has a mark, or indication, of a demand to change communications states, by way of example, by measuring the indications to determine what has been done. a demand to change communications states. In a particular embodiment, the measurement includes at least two positive identifications of the demand in a given time interval. The system can also improve performance by applying a difference in power levels for a non-demand state (that is, steady state or 'maintained control' state) as opposed to a demand state (that is, state of demand). 'change request' communications). The result may include a reduced number of erroneous communications states, such as erroneously assigned or intended traffic channels.

In a particular application, a subscriber unit provides a pulse channel that uses a first code in a CDMA system in a pulse with demand channel using a second code in the reverse link to a base station. The subscriber unit provides the signals with a repetition and, optionally, different power levels in a manner in which a base station uses the principles of the present invention in determining a demand to change the communication states with a probability reasonably high detection and a reasonably low probability of false detection.

The teachings of the present invention are compatible with 1xEV-DV systems and I-CDMA systems, but sufficiently general to support systems employing various other communication protocols used in wired and wireless communication systems. Multiple Access Systems by Code Division (CDMA) such as IS-2000 and Orthogonal Frequency Division Multiplexing (OFDM) systems, such

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As the wireless local area network (LAN) according to the IEEE 802.11a standard, you can use an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing objective and other objectives, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings, in which similar references refer to same parts through different tracks. The drawings are not necessarily to scale, instead, emphasizing their placement in the illustration of the principles of the invention.

Figure 1 is a schematic diagram of a communications system in which an embodiment of the present invention can be developed;

Figure 2A is a schematic diagram of a subsystem used by a base station in the communications system illustrated in Figure 1, which is used to determine whether a reverse link signal includes an indication of a change demand in the communication states ;

Figure 2B is a flow chart of a process executed by a state machine in the subsystem represented in Figure 2A;

Figure 3A is a signal diagram of a 1xEV-DV signal with a first marker indicating 'control maintained' and a second marker indicating a 'demand to go into active state';

Figure 3B is a signal diagram of a multiple access set by code division (CDMA) of code channels having a marker in an assigned time interval indicating that the mobile unit is demanding a change in the communication states;

Figure 3C is a signal diagram of an alternative embodiment of a reverse link signal having the indications; Y

Figure 4 is a plot of the signal-to-noise ratio with respect to the probability of detection that can be used in determining the energy levels of the indications in the signals represented in Figures 3A-3C.

DETAILED DESCRIPTION OF THE INVENTION

A description of the preferred embodiments of the invention is provided below.

The cost of absent or erroneous detection of pulse signals (HB) and pulse with demand to enter active status (HB / RQST) is high. If a false detection for HB occurs, the power control orders and timing orders used between a base station and the mobile terminal can be generated based on a received code phase that is not correct. In this way, the power control can be wrong and not based on the actual power received from the terminal. For the demand message, resources will have to be assigned to a user when resources are not needed, which results in wasted capacity.

Traditionally, if a very low probability of false detection is important, a requirement of a very high threshold of the Eb / No ratio (that is, energy per bit relative to noise density) at the Base Transceiver Station (BTS). As an alternative, if the detection speed is less important, as in the case of the HB signal, multiple successive detections may be useful. This allows the probability of false detection to be greatly reduced.

As an example, if you have P (fd) = 0.01 and if three detections in a row are specified to be made before a “Valid Detection” is determined, the overall probability P (fd) = (0.01) A3 or 0.000001 . The foregoing is less expensive for detection since the probability is much higher at the beginning. As an example, if the probability of single detection is 0.9, which requires three detections that lower the probability of detection to 0.9A3 or 0.72, it is only a slight reduction. This technique is known in radar systems, but has not been used in this application to detect HB and HB / RQST signals and other communications systems and applications. It should be understood that the HB and HB / RQST signals are examples of signals to which the teachings of the present invention can be applied and are not intended for limitation in any way.

The signals to be detected and accounted for (i) can be successive - in due time or in the time interval assigned by the user in a TDMA system, as an example, - or (ii) may have interruptions between the

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signals but have a given number of pulses, bits or other indicators in a given time interval. For a reverse CDMA link, the requirement of multiple serial or non-serial detections can be used for qualification as a system level detection. In addition, the system can set a different power control objective unlike the detection objective, which means that for a lower transmission power, the integration time is increased to increase the energy for detection. For a system that uses temporary intervals, the system may include intelligence to monitor successive or non-successive time intervals for the given user. In addition, the system works with signals blocked and not blocked by logic gates.

The level of interference of the pulsations is derived as a problem of detection of classic RADAR. For this purpose, the advantages are made possible on the basis of the pulse pulses that are “detected” and not demolished as in the case with the technology of the Dedicated Control Channel (DCCH) and Control Mode Maintained Slotted (DCHM ) in CDMA technology.

Figure 1 is a diagram of an exemplary communications system 100, similar to the system described above, which employs an embodiment of the present invention. A base transceiver station (BTS) 25 with antenna tower 23 maintains the wireless communication links with each of a plurality of mobile units 42a, 42b, 42c (collectively mobile units 42) as illustrated. Said wireless links are established on the basis of the allocation of resources in a link without return path 70 and a reverse link 65 between the base station 25 and the mobile units 42. Each link 65 or 70 is usually constituted by several link channels logical inverse 55 and several link channels without logical return path 60, respectively.

As illustrated, the communications system 100 supports wireless communications between an interface 50 and a network 20. Under normal conditions, the network 20 is a Public Switched Telephone Network (PSTN) or computer network, such as the Internet, Internet, or Intranet. The interface 50 is preferably coupled to a digital processing device, such as a laptop 12 sometimes referred to as an access unit to provide wireless access to the network 20. Accordingly, the laptop 12 has access to the network 20 on the basis of communications through a combination of wired and wireless data links.

In a preferred embodiment, the link channels without a return path 60 and the reverse link channels 55 are defined in the communication system 100 as Multiple Access Channels by Code Division (CDMA). That is, each CDMA channel is preferably defined by encoding and transmitting data through the channel with an increased sequence of pseudo-random noise (PN) codes. The data encoded in PN is then modulated in a radiofrequency carrier. The foregoing allows a receiver to decipher a CDMA channel from another of which it knows only the particular enhanced PN code assigned for a given channel. In accordance with one embodiment, each channel preferably occupies a 1.25 MHz band consistent with the CDMA IS-95 standard or the 1xEV-DV standard and is capable of transmitting at 38.4 kbps.

A link without return path 70 includes at least four channels of logical links without return route 60. As illustrated, this includes a pilot channel 60PL, a Link Quality Management (LQM) 60L channel, a search channel by 60PG page and multiple 60T traffic channels.

The reverse link 65 includes at least five logical channels 55. As illustrated, this includes 55HS pulse reserve channels, an active 55HRA pulse demand channel, an access channel 55A and multiple 55T traffic channels.

In general terms, the reverse link channels 55 are similar to the link channels without a return path 60 with the exception that each reverse link traffic channel 60T can support variable data rates from 2.4 kbps to a maximum of 160 kbps .

The data between the base station 25 and the mobile unit 42a usually include encrypted digital information, such as web page data. On the basis of the assignment of multiple traffic channels on the reverse link 65 or on the no return route link 70, higher data transfer rates can be achieved on a particular link between the base station 25 and the mobile unit 42a . However, since mobile units 42 compete for bandwidth allocation, a mobile unit 42a may have to wait until resources are free to allocate to traffic channels to transmit a payload of data.

Before describing an exemplary detector system (Figure 2) that can be used to distinguish a pulse signal from a pulse signal with demand, a brief description of example signals will be made with reference to Figures 3A-3C.

In Figure 3A, a 1xEV-DV 160 signal that can be transmitted by the mobile unit is shown having three different states: a state of 'maintained control' 165, a state of 'demand to go into active state' 170 and a state of data traffic 175. In the 'maintained control' state 165, signal 160 does not include an indication of 'demand to go into active state'. In other words, signal 160 remains in an 'inactive' or 'control' state.

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maintained ', which indicates that mobile unit 42a is not demanding traffic channels. The state of 'demand to go to active state' 170 is an indication that the mobile unit is demanding to transmit data in a traffic channel through a reverse link to the BTS 25. In traffic state 175, the data of traffic traffic is transmitted by the mobile unit to the BTS. After the transmission of the traffic data through the reverse link, the signal 160 is reverted to the 'maintained control' state 165 after a transmission of a 'complete data transmission' state (not shown).

Although illustrated as a single signal 160, it should be understood that the signal can be multiple signals, optionally encoded with orthogonal or non-orthogonal codes in mutually exclusive channels. As an example, the 'maintained control' state 165 can be transmitted on a different channel from the 'demand to go active' state 170. Similarly, the traffic data transmitted in a transmission state 175 may be in a separate channel from the other two states 165,170. An example of a multiple channel is described with reference to Figures 3B and 3C.

Figure 3B is an example of a multiple-access Internet Code Division (I-CDMA) signaling diagram that has assigned time slots for users 1, 2, 3, ..., N that are repeated in epoch i 177a, epoch i + 1 177b and so on. The channels are constituted by the pulsation channel 55H, demand channel 55R and traffic channels 55T. Each of these channels has an associated code C1, C2, C3, C4, ..., CN, which allow the signals to be transmitted on mutually exclusive code channels. The transmission and reception systems process the information in the channels using the codes to separate the information respectively included in them in a typical way of CDMA.

In the illustrated example, users 1, 2, 4, 5, 6, ..., N are demanding to remain in an inactive state, indicated by the presence of a signal 180 in the pulse channel 55H. The user 3, however, is demanding to transmit data through a reverse link on the basis of a signal 185 in the demand channel 55R in the first epoch 177a, a signal 185b in the demand channel 55R in the second epoch 177b and possibly additional epochs. In the third epoch 177c, the BTS station 25 has detected the demand to transmit data based on the two consecutive indications 185a and 185b. After receiving a confirmation, the user 3 begins to transmit traffic data 190 on an associated traffic channel using the code C5. In an alternative embodiment, the BTS station 25 may require three consecutive indications 185a to 185c inclusive before determining that a claim is being made and confirmed.

Figure 3C is a more detailed signal diagram of the 1xEV-DV signal of Figure 3A that is used to indicate a state of 'demand to go into active state' to the base station 25 from the mobile unit 42a. In this embodiment, the 1xEV-DV signal is made up of multiple signals in different logical channels: a 55H pulse channel and a 55R demand channel. Pulse channel 55H provides a continuous timing and other information (eg, power level, synchronization, etc.) from the mobile unit 42a to the base station 25. The mobile unit 42a uses the demand channel 55R to make a request (eg, digital "1") of the base station 25 to demand a traffic channel on the reverse link 65 to transmit data.

The sampling times 195a, 195b, ..., 195f (collectively 195) indicated by arrows indicate times or intervals in which the BTS station 25 shows the time intervals of the demand signal 55R and, optionally, the channel of 55H pulsations to determine if a demand is being made for a traffic channel. It should be understood that sampling may occur during the entire time interval or a subset thereof. In addition, the pulsation channel 55H and the demand channel 55R use mutually exclusive codes, in this particular embodiment, whereby sampling is performed on their channels of mutually exclusive codes 55H, 55R in all or a subset of intervals Temporary In a particular embodiment, the base station 25 samples conventional mutually exclusive codes 55H, 55R at time intervals designated to demand indications, such as at time intervals at sampling times 195b, 195d and 195f. During these time intervals, pulse channel 155H is in "inactive" condition, but demand channel 55R is in "active" condition.

As described above, the signals in the time intervals of "active" demand can be modulated messages or simply pilot signals encoded without any "bit". In this way, the detection can be based exclusively on the respective energetic levels of the pulse and pulse signals with demand at respective time intervals during a given time interval or spanning several time intervals.

In a particular embodiment, the indication of the 'maintained control' state 165 has a first level of energy and the state of 'demand to go into active state' 170 has a second level of energy. The base station 25 can benefit from the difference in power levels in addition to the repetition of the pulses used to indicate a demand for passage to active state. As an example, in this particular embodiment, distinguishing two states may be a matter of measuring energy levels of the signals and (i) comparing the energy levels with respect to at least one threshold or (ii) determining that a demand it is present, optionally, in a channel of mutually exclusive codes in time intervals when the pulse signal is at a logic level zero. The energy levels different from the indications can be provided

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by the cycle of signal usage, signal frequency, signal strength, signaling structure, etc.

To understand how the energy levels of the signals can be used to improve system performance, reference can be made to Figure 4, which provides a diagram to select signaling requirements based on the following parameters or factors: (i) probability of detection, P (d) (x axis), (ii) ratio of signal to noise in decibels (y axis) and (iii) probability of false detection, P (fd) (curves in the diagram). This diagram illustrates a signal to noise ratio required at the input terminals of a linear rectifier detector as a function of detection probability for a single pulse, with the false alarm probability P (fd) as a parameter, calculated for a not fluctuating signal. It should be understood that alternative parameters or factors can be used to establish or define the transmitted power levels of the indications.

At the point surrounded by a circle 200, the signal to noise ratio is 3 dB, P (d) = 20%, and P (fd) = 1%. To increase the probability of detection for the same probability of false detection, it is simply necessary to slide the point surrounded by a circle 200 upward along the same probability of the false detection curve, suggesting that an increase in the signal to noise ratio to improve system performance and thus improve the probability that the demand signal will be detected quickly.

Before providing an example model and an examination with respect to the energetic levels of the 55HS reserve pulse signal and the 55HRA active condition pulse demand for the example 100 communications system (Figure 1), a brief discussion of A processor and detector that can be used in the system is provided below.

Figure 2A is a schematic diagram of a demand detection processor 110 used to determine if the mobile unit 42a has demanded the data send to the BTS station 25. The receiver Rx 35 receives signals 55, which includes the maintenance channel 55M , the traffic channels 55T, the access channel 55A, the reserve pulse channel 55HS and the active pulse demand channel 55HRA. The signal 55 is processed so that a pulse channel processor 112 receives the pulse reserve channel 55HS and a demand channel processor 114 receives the pulse demand channel in active condition 55HRA.

The pulse channel processor 112 and the demand channel processor 114 includes the same processing elements, in this particular embodiment, whereby an operational description of only the pulse channel processor 112 will be provided for brevity purposes. .

The pulse channel processor 112 receives the pulse reserve channel 55HS. A correlator 115 uses a so-called despreader 120 to de-extend the pulsation reserve channel 55HS. An integrator 125 is used to coherently combine the pulse signal. By coherently combining the signal, an integration of I, Q and its phase causes the phase of the signal to be eliminated and the power of the signal to be provided.

After the correlator 115, a rectifier 130 (that is, absolute value of the quadratic signal, rectifies the power of the signal, which is then integrated by a second integrator 135 to calculate the energy of the received pulse signal. The second integrator 135 provides a non-coherent signal combination, which is calculated for short time intervals.The non-coherent integration provides only magnitudes if the terminal travels too fast, which causes a 180-degree phase point crossing, which results in it can cause ambiguities in determining the signal energy in the absence of the non-coherent combination.

The output from the pulse channel processor 112 is an energetic level of pulsation and the output from the demand channel processor 114 is an energy level of demand. Each of these energy levels, in this particular embodiment, is fed to a hypothesis detector 140, which determines whether a pulse signal, demand signal or no signal is in signal 55 received by base station 25.

The output of the hypothesis detector 140 is provided to a state machine 145. The state machine is used to determine if the mobile unit is making a 'demand to go into active state' in accordance with a given criterion, where, in a particular embodiment is a measurement of the output from the hypothesis detector 140. The example measurements include the count of the number of consecutive demand signals, the measurement of a ratio of pulse reserve channel signals and channel signals active pulse demand, the count of active pulse demand signals in a given time interval, etc. In addition, the hypothesis detector 140 and the difference in energy levels of the indications improve system performance, but are not required for the present invention. In other words, the pulse reserve channel 55HS and the active pulse demand channel 55HRA can be processed directly by the state machine 145 to determine if the mobile unit 42a is demanding the passage to the active state. More details are provided after a description of one embodiment of the state machine 145.

In this particular embodiment, state machine 145 provides a true or false Boolean signal. An example of a process executed by the state machine is illustrated in Figure 2B.

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Figure 2B is an exemplary flow chart of state machine 145. The example state machine 145 starts operation in step 205 when the detection processor 110 is 'initialized'. In step 210, the machine of states 145 initializes counters that are used to determine if a detection has occurred. In step 215, the state machine 145 receives the output from the hypothesis detector 140. After the operational start, the state machine 145 can act as an 'interrupt service routines', beginning in step 215, at Receipt of any output from the hypothesis detector 140. The counters are reset (that is, reset) to a determination of a detection or a non-detection to restore the measurement process without a reset of the detection processor 110, as described below.

After receiving the output from the hypothesis detector 140 in step 215, the state machine 145 determines whether or not the output of the hypothesis detector 145 is a demand (that is, 'demand to go to active state') . If the answer is yes, in this case, the state machine 145 continues in step 240 in which a detection counter is incremented. In step 245, the detection counter is compared with respect to a threshold value. If the detection counter exceeds the threshold, in this case, in step 250, the state machine 145 reports a detection of a 'demand to enter the active state' from the mobile unit 42a. If the detection counter does not exceed the threshold value, in this case, the state machine 145 returns to step 215 and is waiting to receive another output from the hypothesis detector 140.

Continuing the reference to Figure 2B if, in step 220, the output of the hypothesis detector 140 is determined to be not a 'demand', then the state machine 145 continues in step 225. In step 225, the state machine 145 increases a non-detection counter. In step 230, a determination is made as to whether the non-detection counter exceeds a threshold value. If the answer is yes, in this case, the state machine 145 continues in step 235, in which the state machine 145 reports a non-detection of a 'demand to go into active state' by the mobile unit 42a. If the non-detection counter does not exceed the threshold value, in this case, the state machine 145 continues in step 215.

After steps 235 and 250, the state machine 145 performs the zero reset of the counters in step 255, which allows the state machine 145 to detect future 'demands to move to active status' by the mobile unit 42a. In step 260, the state machine 145 ends its action.

The detection counter is used by the state machine 145 to determine how many indications of a 'demand to enter active state' have been received by the detection processor 110 in accordance with a given criteria. The criterion can be in any form, including a given number of consecutive detections, a given number of detections in a given time interval or a relation of detections to non-detections. Alternatively, non-count based measurements can be used to determine if a demand is being made to go into active status, such as measuring the phase of the demand signals.

It should be understood that alternative ways of using counters or other criteria can be used by state machine 145. By way of example, state machine 145 can use other process flows, non-counter variables or other standard or non-standard techniques. standard to determine a detection. In addition, instead of receiving the output from the hypothesis detector 140, the input to the state machine 145 may be raw data from the pulse channel processor 112 or the demand channel processor 114. In addition, in a form Alternatively, the state machine 145 may be included in combination with the hypothesis detector 140.

Referring again to Figure 2A, in addition to using the state machine 145 to find out with high probability of whether the mobile unit 42a is making a 'demand to go into active state', also using the hypothesis detector 140.

To determine which signals are present, the hypothesis detector 140 includes logical functions. As an example, in this particular embodiment, the hypothesis detector 140 compares a first energy level threshold with respect to the first energy level (i.e., energy level of the pulse) and compares a second energy level threshold with respect to at the second energetic level (that is, energy demand level).

The thresholds of energy levels, by way of example, with respect to what compares the energy level of the pulse and the energy level of the demand, are 9 dB and 11 dB, respectively. The thresholds of energy levels can be dynamically selected, predetermined or applied in another way, such as on the basis of a transmitted power level, which can be communicated by the mobile unit to the base station through the 55HS pulse reserve channel, as an example. In the case of the calculation of the energy level and its comparison, the first and second energy levels may be dependent on the occupation of the time intervals in the signaling channels used by the signal 55, so that the thresholds of energy levels can be based in a predicted or specified number of bits "1" used to indicate a 'demand to go into active state' or to indicate a demand to remain in idle mode. The use of energy level thresholds is examined in connection with a US patent application entitled "Pulse signal transmission at a level lower than the pulse demand", by Proctor, J., filed at the same time

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that this, whose complete teachings are incorporated herein by reference.

As described above, the output of the hypothesis detector 140 is measured by the state machine 145 determining whether or not to change the state of the communications system, which is the state of the reverse link traffic channels between the unit. mobile 42a and the base station 25. By way of example, if the hypothesis detector 140 determines that a 'demand to enter the active state' is being made (that is, to send a data transmission on the reverse link) through the mobile unit 42a, in this case, the state machine 145 provides a signal to a processor (not illustrated) at the BTS station 25 which is responsible for providing the laptop 12 with a traffic channel 55T. In a particular embodiment, the BTS station 25 assigns the traffic channel 55T if the number of consecutive demand signals is determined to be two or more consecutively. Alternative criteria have been described previously.

As described with reference to Figure 3C, the pulse channel processor 112, the demand channel processor 114 and the hypothesis detector 140 can be configured or designed in a manner that monitors an occupation of time intervals used to indicate the change demand for communications states. In one embodiment, the detection includes the supervision of the occupation of mutually exclusive code channels, such as those illustrated in Figures 3B and 3C.

A feedback loop (not shown) can be used to make the pulse channel processor 112 and the demand channel processor 114 "adaptive". By way of example, on the basis of the energy level received from the pulsation channel 55H, the integration time of the integrators 125, 135, and the thresholds of energy levels used by the hypothesis detector 140 for comparing the energy levels can be adjusted of the pulse and demand signals that can also be adjusted through the feedback loop. Other operational feedback may cause (i) the number of consecutive pulses required for a detection to be increased or decreased or (ii) the number of transmitted demand signals is increased or decreased. Said feedback loop may use an order or message to transfer information between the BTS station 25 and the mobile unit 42a that includes information regarding the repetition of pulses or energy levels of the pulse and pulse signals with demand transmitted by the mobile unit. 42a.

As described above, the first communications status may be a reserve status and the second communications status may be a payload status. In other systems, or even in the same system, the communication states may refer to other communication states, such as a demand to change the base stations, power control signaling, etc. The use of different signal repetitions or energetic levels in signaling, as described here, is applicable to wireless, wired or optical communications systems. In either case, the communication states can be used in data or voice communications systems.

As also described above, the second energy level may be based on an objective probability of detection, false detection or combination of both as described with reference to Figure 4. In other words, the mobile unit can transmit the signal of demand at a given power level or a given number of pulses per given period of time to achieve a corresponding signal to noise ratio for a given target probability of detection, false detection or both at the same time as described by referring to the Figure Four.

An analysis can be used to establish the transmission power or the number of transmitted indications, or the above-mentioned feedback mechanism can be used in the communications system to make the mobile unit change its behavior in terms of making the received energy levels of the indications reach a predetermined signal to noise ratio, thus providing the desired probability of detection and the false detection parameters.

SIMULATION

A simulation for a reverse link was performed when the reverse link is assumed to have power control and a pulse channel of any of the types of examples illustrated in Figures 3A to 3C or other type of communication link signaling.

First, there are two assumptions that have been made for this simulation. First, power control is used in a combination of detected routes or in a single route. Power control is performed even when a positive detection is not achieved. Second, the probability of detection was set to achieve detection at a sufficiently high rate to ensure that the power control is performed on the correct signal. For clarification purposes, detection is required to track the registration of the received signal.

Table 1 indicates the detection rate required for a single route channel from a vehicle that moves away from the base station at a speed of 60 mph. This table requires that there is at least one detection bias of an integrated circuit due to movement.

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 Bias distance for 1 integrated circuit

 814 feet

 Handset Speed

 60 mph

 Handset Speed

 88 feet / second

 Integrated circuit bias rate

 9.2 integrated circuits / second

 Pulsation rate

 50 HB / s

 Press s / Td

 462

Table 1

In Table 1, the time period Td is defined as the period during which a single pulse pulse must be detected to ensure that the signal is subject to registration when at the time of the arrival of the signal it is subject to bias due to the vehicle movement. Table 1 indicates that one of every 462 pulses must be received for a very high probability or there is a risk of losing signal tracking.

Based on this calculation, the threshold detection was established from a table of probabilities of false detection / detection (eg, Figure 4). Although Table 1 is defined for the so-called Additive White Gaussian Noise (AWGN), it is expected that the detection probabilities will not be greatly affected for a relatively short period of time. This is due to the statistical independence of the fading from pulse pulse to pulse pulse.

Although the probabilities of individual detection impulses varied markedly, the overall results did not turn out to vary significantly by more than a factor of approximately 50% in the detection latency. More specifically, the average detection latency for the demand message in AWGN was 11 ms compared to approximately 15 ms for 30 km / h. Again, this result is due to a detection process rather than a more difficult demodulation process.

Based on this analysis, a detection probability of 20% and a false detection of 1% were selected. The foregoing requires an average Eb / No value of 3 dB. The above is illustrated by referring to the Figure

Four.

Table 2 indicates a calculation of the probability of detection and false detection during the time Td defined above.

 E / Io target value (total energy / interference density)

 3 dB

 Probability of detection

 0.2

 Probability of false detection

 0.01

 Probability of detection for 3 sequential HBs

 8.00E-03

 Number of tests in Td

 462

 Probability of no detection in Td

 2.44E-02

 Probability of false detection for 3 sequential

 1.00E-06

 Tests required for non-false detection

 462

 Probability of false detection for Td

 4.62E-04

Table 2

To reduce the probability of false detection, three sequential detections were needed to validate a unique detection. Since the probability of false detections is multiplicative in this case, the probability of a single false detection is cubed.

Table 3 below calculates the average Ec / Io ratio (energy per integrated circuit) with respect to the interference density, which is the SNR ratio integrated during the entire integrated circuit) that is required to achieve the statistics in Table 2.

 E / lo objective

 3 dB

 Processing gain

 256

 Rafaga Ec / Io

 -21.08 dB

 Half Ec / Io

 -40.9 dB

Table 3

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Since the pulsation channel is multiplexed by time division (TDM) in the structure, the interference for all other users due to the pulsation users increases as follows:

Effective mean of Ec / Io (all HB users) = 10 * log10 (N) -40.9, where N is the number of users.

Thus, for 96 users of a given base station, the average total interference will be equal to the Burst Ec / Io ratio or -21.08 dB.

EXAMPLES

1. In a wireless communications system, a method for determining a demand for a change in communication status, whose method comprises:

receive at least one signal that has a first indication of a first communication state and a second indication for change demand for a second communication state;

count at least one of the indications; Y

Based on the measurement, determine if a demand for change of communication states has been made.

2. The method according to example 1, wherein the determination step includes comparing the number of second indications received with respect to a threshold of at least two.

3. The method according to example 2, wherein the count of the detected indications is reset for non-consecutive detected indications.

4. The method according to example 2, wherein the counting of the indications detected is subject to reposition if said threshold of at least two second indications is not achieved within a given time interval.

5. The method according to example 1, which also includes the supervision of at least a first and second time intervals for said first and second indications.

6. The method according to example 5, wherein the detection includes applying independent thresholds for detection to the indications.

7. The method according to example 5, wherein the time intervals are mutually exclusive.

8. The method according to example 7, wherein a demand for communications status originates by detecting a repetition of the first and second indications above a given threshold value, and a demand not to change the communication states originates by detecting a repetition of less than the first and second indications above a given threshold value.

9. The method according to example 1 which also includes having a current communication status change in response to a determination that a claim has been made.

10. The method according to example 1 wherein the first indication has a first energy level and the second indication has a second energy level and also includes the detection of the indications based on the energy levels in accordance with an alternative criterion .

11 The method according to example 10 wherein the detection includes comparing the first energy level with respect to a first threshold of energy levels and comparing the second energy level with respect to a second threshold of energy levels.

12. The method according to example 11 wherein the detection includes integrating time intervals into a signal channel in which said at least one signal is received, said first and second energy levels being dependent on the occupation of the time intervals.

13. The method according to example 11 wherein the criterion includes at least one of the following: the first energy level exceeds a first threshold of energy levels, the second energy level exceeds a second threshold of energy levels, the second indication occupies time intervals , the first and second indications occupy time intervals in mutually exclusive code channels and the first and second indications occupy mutually exclusive time intervals.

14. The method according to Example 13, wherein the indication count includes the count of only indications that are detected on the basis of the energy levels in accordance with the alternative criteria.

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15. The method according to example 14 which also includes adjusting the basis of an objective probability of detection.

16. The method according to example 14 which also includes the base adjustment of an objective probability of false detection.

17. The method according to example 1, wherein the first communication state is a reserve state and the second communication state is a payload state.

18. The method according to example 1, wherein the communication states are data communication states.

19. The method according to example 1, wherein the communications system is a wireless system of multiple access code division code (CDMA) or orthogonal frequency division multiplexing (OFDM).

20. In a communications system, an apparatus for determining a demand for a change in communication status, said apparatus comprising:

a receiver to receive at least one signal that has (i) a first indication of a first communication state and (ii) a second indication of a demand for change to a second communication state;

a counter coupled to the receiver to count at least one of the first and second indications; or

a logic unit coupled to the unit of measure to determine whether or not a demand for changing communication states has been made.

21. The apparatus according to example 20, wherein the logic unit compares the number of second indications received with respect to a threshold value of at least two.

22. The apparatus according to example 21, wherein the counter is subject to reset for non-consecutive detected indications.

23. The apparatus according to example 21, wherein the counter is reset if said threshold of two detected indications is not achieved within a given time interval.

24. The apparatus according to example 20 which also includes at least one monitor to control at least the first and second time intervals for said first and second indications.

25. The apparatus according to example 24, wherein the unit of measurement applies independent thresholds for the detection of the indications.

26. The apparatus according to example 24, wherein the time intervals are mutually exclusive.

27. The apparatus according to example 26, wherein the logic unit causes a demand for changing communication states in response to the determination of repetition rates greater than the respective thresholds at mutually exclusive time intervals, and the logic unit does not cause a demand for changes in communications states in response to the determination of repetition rates higher than the respective thresholds in less than both mutually exclusive time intervals.

28. The apparatus according to example 20 which also includes a state control unit coupled to the logic unit used to change the communication status in response to a detection that a demand has been made.

29. The apparatus according to example 20, wherein the first indication has a first energy level and the second indication has a second energy level and where the meter counts the indications on the basis of the energy levels in accordance with criteria Alternative

30. The apparatus according to example 29, wherein the unit of measure includes a comparator to compare the first energy level with respect to a first threshold of energy levels and to compare the second energy level with respect to a second threshold of energy levels.

31. The apparatus according to example 29, wherein the unit of measurement includes the integration of time intervals in a signaling channel in which said at least one signal is received, said first and second energy levels depending on the occupation of the intervals Temporary

the second energetic level of the signal over that of the second energetic level of the signal over the

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32. The apparatus according to example 29, wherein the criteria include at least one of the following: the first energy level exceeds a first threshold of energy levels, the second energy level exceeds a second threshold of energy levels, the second indication occupies intervals temporary, the first and second indications occupy temporal intervals in mutually exclusive code channels and the first and second indications occupy mutually exclusive temporal intervals.

33. The apparatus according to example 29, wherein the meter counts only indications that are detected on the basis of energy levels in accordance with the alternative criteria.

34. The apparatus according to example 33, which also includes adjusting the second energy level of the signal based on an objective probability of detection.

35. The apparatus according to example 33, which also includes adjusting the second energy level of the signal based on an objective probability of false detection.

36. The apparatus according to example 20, wherein the first communications state is a reserve state and the second communications state is a payload state.

37. The apparatus according to example 20, wherein the communication states are data communication states.

38. The apparatus according to example 20, wherein the communications system is a wireless communications system with multiple access by code division (CDMA) or orthogonal frequency division multiplexing (OFDM).

39. In a wireless communications system, an apparatus for determining a demand for a change in communications status, the apparatus of which comprises:

means for receiving at least one signal having (i) a first indication of a first communication state and (ii) a second indication for a demand for change to a second communication state;

means for counting the indications detected; Y

means to determine whether or not a claim has been made to change communications states.

40. In a communications system, a method for making a demand for a change in communications status, said method comprising:

select indications to be transmitted in a signal, the indications associated with data communication states and capable of counting by a reception system to determine whether or not a demand has been made to change the communication states; Y

transmit the signal that includes at least one indication to the reception system.

41. The method according to example 40, wherein the indications are transmitted consecutively in the expectation that they be counted as consecutive indications for the reception system.

42. The method according to example 40, wherein at least two indications detected are included in the signal in a given time interval.

43. The method according to example 40, wherein the selection of the indications is carried out in accordance with the energetic levels associated with the indications.

44. The method according to example 40, wherein signal transmission includes multiplexing the indications at time intervals in a signaling channel.

45. The method according to example 40, wherein the signal transmission includes the application of the signals to the signal in at least one of the following ways: in mutually exclusive code channels, in mutually exclusive time intervals, in time intervals vacancies, with respective energy levels, with a given repetition rate or as an uncoded carrier signal.

46. The method according to example 40, wherein the communication states include a reserve status and a payload status.

47. The method according to example 40, wherein the communication states are communication states of

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data.

48. The method according to example 40, wherein the respective energy levels are based on an objective probability of detection.

49. The method according to example 40, wherein the respective energy levels are based on an objective probability of false detection.

50. The method according to example 40, wherein the communications system is a wireless system of multiple access code division code (CDMA) or orthogonal frequency division multiplexing (OFDM).

51. In a communications system, an apparatus for making a demand for change in the state of the communication, said apparatus comprising:

a selector to select indications to be transmitted in a signal, the indications being associated with communication states and quantifiable by a reception system to determine whether or not a demand has been made to change a communication state; Y

a transmitter coupled to the selector to transmit the signal that includes at least one indication to the reception system.

52. The apparatus according to example 51, wherein the selector selects the indications in a manner in which the indications are transmitted consecutively in the expectation of being counted as consecutive indications by the receiving system.

53. The apparatus according to example 51, wherein the selector selects at least two indications to be included in the signal in a given time interval.

54. The apparatus according to example 51 which also includes a multiplexer coupled to the selector and transmitter to apply the indications at time intervals in a signaling channel.

55. The apparatus according to example 51, wherein the selector and the transmitter apply the indications in at least one of the following ways: in mutually exclusive code channels, in mutually exclusive time channels, in vacant time intervals, with energy levels respectively, with a given repetition rate or as an uncoded carrier signal.

56. The apparatus according to example 51, wherein the communication states include a reserve status and a payload status.

57. The apparatus according to example 51, wherein the communication states are data communication states.

58. The apparatus according to example 51, wherein the selector applies the indications to the signal based on an objective probability of detection.

59. The apparatus according to example 51, wherein the selector applies the indications to the signal based on an objective probability of false detection.

60. The apparatus according to example 51, wherein the communication system is a wireless communications system with multiple codes division code access (CDMA) or orthogonal frequency division multiplexing (OFDM).

61. In a communications system, an apparatus makes a demand for a change in communication status, said apparatus comprising:

means for selecting indications to be transmitted in a signal, the indications associated with the communication states and quantifiable by a reception system to determine whether or not a demand for changing a communication status has been made; Y

transmission means for transmitting the signal that includes at least one indication towards the reception system.

Although this invention has been particularly illustrated and described with reference to its preferred embodiments, it will be understood by those skilled in this art that various changes in its form and details can be made without deviating from the scope of the invention set forth by the claims. attached.

Claims (8)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 65 1. A mobile unit (42) comprising: means for transmitting, at a base station, signals (165, 170) that have different formats in terms of different power levels in time intervals where the mobile unit is not transmitting data, the means for transmitting signals that have different formats that they comprise means to demand, in at least one of the different formats (170), for the mobile unit, resources to transmit data; at least two of the different formats (170) being associated with different power levels; means for applying a first power level for a non-demand state and means for applying a second power level for a demand state; means for receiving information indicating the resources that allow data to be transmitted, in response to the demand made by the mobile unit (42), for the resources that allow data to be transmitted; means for assigning an orthogonal sequence and means for deriving the transmitted signals from the orthogonal sequence; characterized by means for transmitting signals for the state of non-demand and signals for the state of demand in a channel of mutually exclusive codes in time intervals when a pulse signal is at a logical zero level. 2. The mobile unit according to claim 1, further comprising: means to use the mobile unit in a Multiplexing system by Division of Orthogonal Frequency, OFDM. 3. The mobile unit according to claim 1, comprising means for deriving, in addition, the signals transmitted from a pseudo-noise sequence. 4. The mobile unit according to claim 1, further comprising: means for repeating the demand by the mobile unit for the resources destined to transmit up to the information indicating that the data transmission resources are received. 5. A method implemented in a mobile unit (42) comprising: transmit signals (165, 170), which have different formats in terms of different power levels, in time intervals to a base station; where the transmitted signals are transmitted in the time intervals in which the mobile unit is not transmitting data; at least one of the different formats (170) being configured to include a demand by the mobile unit of resources to transmit data; wherein at least two of the different formats (170) are associated with different power levels; wherein a first power level is applied for a non-demand state and a second power level is applied for a demand state; receive information indicating the resources for the transmission of data in response to the demand by the mobile unit (42) of the resources for the transmission of data; characterized in that the mobile unit (42) is assigned an orthogonal sequence and the transmitted signals are derived from the orthogonal sequence; where the signals for the non-demand state and the signals for the demand state are transmitted in a channel of mutually exclusive codes in time intervals when a pulse signal is at a logical zero level. 6. The method according to claim 5, wherein the mobile unit operates in a Multiplexing system by Division of Orthogonal Frequency, OFDM. 7. The method according to claim 6, comprising the derivation of the signals transmitted from a pseudo-noise sequence. 8. The method according to claim 6, comprising the repetition of the demand by the mobile unit for the resources destined to transmit data up to the information indicating that the data transmission resources are received. 10