RU2372739C2 - Method of gaining of access to radio communication system with possibility of tuning - Google Patents

Abstract

FIELD: information technologies.

SUBSTANCE: for the purpose of access to first communication system, terminal determines time of transmission of access attempt, expected time of system response and secure time period, on the basis of transmission time and/or expected time of response, terminal determines point of start time for transmission of access attempt in such a way that secure time period not to overlap with tuning interval in which terminal should control another frequency. This point of start time may be set initially to the end of previous access attempt plus pseudo-random wait state and may be moved back or forth in time if required for time period chosen considering secure period.

EFFECT: possibility of access to first communication system and tuning to second communication system in certain time periods.

29 cl, 9 dwg

Description

I. Cross reference to related applications

This application claims priority to provisional patent application US No. 60/649 959, registered February 3, 2005, entitled "Method to Allow Monitoring of IS2000 / IS95 System During IXEVDO Access Channel Operation for Hybrid Access Terminals", and provisional patent application US No. 60 / 698 566, registered July 12, 2005, entitled "Techniques for Accessing a Wireless Communication System with Tune-Away Capability".

II. Technical field

The present disclosure relates generally to communication, and more specifically to techniques for accessing and monitoring radio communication systems.

III. State of the art

Radio communication systems are widely deployed to provide various communication services, such as voice, packet data, video, broadcast, messaging, etc. These systems may be multiple access systems capable of communicating with multiple users by sharing available system resources. Examples of such multiple access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiplexing (OFDM) systems and managed access multiple access (ODMA). A CDMA system may implement a radio access technology (TRD) such as Broadband CDMA (W-CDMA) or cdma2000, which covers IS-2000, IS-856, and IS-95 standards. A TDMA system may implement a turbojet engine, such as a global system for mobile communications (GSM). These various turbojet engines and standards are known in the art.

Some radio communication systems are capable of providing voice and packet data services, which may be referred to as “data and voice” transmission systems. One such system is the 1xEV-DV (Development: Data-Voice) system, which embodies IS-2000 and / or IS-95. Voice and packet data services have various characteristics. For example, a voice service usually requires the same quality of service (GoS) for all users, and also has relatively strict latency requirements. In contrast, packet data transmission may allow different GoS for different users and delay variables. To support both voice and packet data services, the 1xEV-DV system may first allocate system resources to users of voice services and then distribute any remaining system resources to packet data users that may allow longer delays.

Some radio communication systems, which may be referred to as data-only systems, are optimized for packet data transmission. One such system is the 1xEV-DO (“Data Optimized Development”) system, which embodies the IS-856. Packet data transmission is typically characterized by long periods of silence that are interrupted by traffic packets.

A service provider can deploy multiple radio systems to provide advanced services to its subscribers. For example, a service provider may deploy a 1xEV-DV system to provide voice and packet data for a large geographic area and may deploy a 1xEV-DO system to provide packet data for areas where packet data usage is expected to be high. The coverage areas of these two systems usually overlap.

The hybrid terminal can communicate with 1xEV-DV and 1xEV-DO systems. A terminal can usually receive services from one of these two systems at any given time, depending on the location of the terminal and the required service. The terminal can be registered in the 1xEV-DV system and can control this system with respect to paging and other messages. The terminal may then try to access the 1xEV-DO system to receive packet data services. The terminal will then enter the 1xEV-DO access state and perform a series of tasks to gain access to the 1xEV-DO system. During the time that the terminal is in a 1xEV-DO access state, the terminal is usually not able to control the 1xEV-DV system with respect to paging and other messages. Therefore, the terminal may miss an incoming call while trying to access the 1xEV-DO system, which is very undesirable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the deployment of 1xEV-DV and 1xEV-DO systems.

FIG. 2 shows a timing diagram for a paging channel in a 1xEV-DV system.

FIG. 3 shows a timing chart of accessing a 1xEV-DO system.

FIG. 4 shows control of a 1xEV-DV paging channel and access to a 1xEV-DO system using a conventional terminal.

FIG. 5 shows tunable access probe transmission.

FIG. 6 shows a timing diagram of a rebuilding access procedure.

FIG. 7 shows a process for gaining access to a 1xEV-DO system with the ability to tune out to a 1xEV-DV system.

FIG. 8 shows a rebuilding process of gaining access to a system.

FIG. 9 shows a block diagram of a hybrid terminal.

DETAILED DESCRIPTION

The word “exemplary” is used in this work to mean “to be an example, case, or illustration”. Any embodiment or construction described herein as “exemplary” need not be construed as preferred or advantageous over other embodiments or constructions.

This paper describes the methods of gaining access to the first communication system (for example, to the 1xEV-DO system) with the ability to tune to the second communication system (for example, to the 1xEV-DV system). For clarity, these techniques are described below specifically for the 1xEV-DV system and the 1xEV-DO system.

In a preferred embodiment, the terminal determines a secure time interval for the access probe (request) to be sent to the first system, and a start time point for transmitting the access probe so that the secure time interval does not overlap with the tune-off interval in which the terminal must be detached from the first system . The terminal then transmits an access probe to the first system at a given start time.

In one embodiment, the terminal transmits at least one access probe to gain access to the first system, and may need to wait a pseudo-random period of time between access probes. The terminal may also need to tune its receiver to the second system at specific time intervals, which are called tune-off intervals, to receive paging and other messages and / or to perform other tasks.

To gain access to the first system, the terminal determines the transmission time of the access sample and the expected response time for confirmation from the first system for the access sample. The terminal then determines a secure time interval for the access probe based on the transmission time and / or the expected response time. Protected time interval - the time interval in which the receiver is tuned to the first system, and it can be equal to the expected response time or transmission time plus the expected response time. The terminal then determines the start time (for example, the start of the access channel cycle) for transmitting the access sample so that the protected time interval does not overlap with the tune-off interval in which the terminal is tuned to the second system, for example, to control the paging channel. This trigger time can be initially set to the end of the previous access probe plus a pseudo-random waiting period. This trigger time can be moved forward or backward in time, if necessary, for a period of time selected so that the protected time interval does not overlap with the offset interval. The terminal then transmits an access probe to the first system at the time of startup. The terminal can tune to the second system before the tune-off interval, perform any necessary task in the second system, and then tune back to the first system at the end of the tune-off interval. The terminal may transmit each subsequent sample in a similar manner.

FIG. 1 shows an example deployment 100 through which a 1xEV-DO system overlaps with a 1xEV-DV system. The 1xEV-DV system includes a plurality of base stations 110 that provide voice and packet data for terminals 130 located within the coverage area of these base stations. Similarly, the 1xEV-DO system includes a plurality of base stations 120 that provide packet data for terminals 130 located within the coverage areas of these base stations. Base stations 110 and 120 may be located in various places or co-located in the same places. The base station controller (BSC) 142 is connected to the base stations 110 and provides coordination and control of these base stations. Similarly, BSC 144 is connected to base stations 120 and provides coordination and control of these base stations. BSC 142 and 144 may optionally connect to a network entity 140 that supports communication between a 1xEV-DV system and a 1xEV-DO system.

In general, a base station (1xEV-DV terminology) is a fixed station used to communicate with terminals and may also be called an access point (1xEV-DO terminology), Node B (W-CDMA terminology), and base transceiver station (BTS) , or some other terminology may be used. A terminal can be a fixed or mobile phone and can also be called a mobile station (1xEV-DV terminology), access terminal (1xEV-DO terminology), user equipment (W-CDMA terminology), wireless device, subscriber unit, or some other terminology can be used . In the description below, the term “base station” is used for a fixed station, and the term “terminal” is used for a wireless device that communicates with a fixed station.

In FIG. 1, a solid line with arrows at both ends indicates communication between the terminal and the base station. A dashed line with an arrow at one end indicates the reception of a pilot signal and / or signaling by the terminal from the base station. A terminal may communicate with one or with a plurality of base stations via a forward communication channel and / or a reverse communication channel at any given moment. A forward communication channel (or downlink) refers to a communication channel from base stations to terminals, and a reverse communication channel (or uplink communication channel) refers to a communication channel from terminals to base stations.

The hybrid terminal can be registered in the 1xEV-DV system and can operate in a “standby” state when the terminal does not actively exchange data with any base station in the 1xEV-DV system. In the standby state, the terminal typically monitors the paging channel (PCH) from the 1xEV-DV system for messages that correspond to that terminal. Such messages may include paging messages that alert the terminal to an incoming call, and service messages that carry system and other information for the terminal.

In IS-2000 and IS-95, the paging channel is divided into PCH slots. Each PCH slot has a duration of 80 milliseconds (ms). The terminal is allocated one PCH slot in each slot cycle having a duration of T _sc seconds, which is defined as:

(1)T _sc = 1.28 × 2 ^SCI ,

(one)

where SCI is the slot cycle index applied to the terminal and which the terminal can negotiate with the system. SCI can range from -4 to +7, and the slot cycle can last from 80 ms to 163.84 seconds, respectively. Each slot cycle contains 16 × 2 ^SCI PCH slots, which are assigned indices from 1 to 16 × 2 ^SCI . The terminal is assigned a specific index of the PCH slot, which is determined using the identification information of the terminal. This identification information may be an International Mobile Subscriber Identity (IMSI), which is unique for each terminal, Mobile Identification Number (MIN), Electronic Factory Number (ESN), Temporary Mobile Subscriber Identity (TMSI), etc. The terminal PCH slot index is fixed, and each PCH slot with this slot index is called a dedicated paging slot. The terminal processes a dedicated paging slot in each slot cycle, since a message can be sent to the terminal in this paging slot.

FIG. 2 shows a timing diagram of paging channel processing by a terminal in a 1xEV-DV system. To save battery power in the “standby” state, the terminal can operate in slot mode, according to which (1) the 1xEV-DV system transmits messages to the terminal only in dedicated paging slots and (2) the terminal controls the paging channel with respect to messages during the allocated slots paging. In slot mode, the terminal switches from an inactive state to an active state before a dedicated paging slot in each slot cycle, controls the paging channel and performs other functions to maintain a communication channel with the 1xEV-DV system. The active time indicates the period of time when the terminal is in the active state, and the inactive time indicates the period of time when the terminal is in the inactive state. The active time usually covers a dedicated paging slot, any necessary installation and update time for the data within the terminal, and the program overhead time and the “clear” time. The active start times for consecutive dedicated paging slots are separated by Tsc seconds.

The hybrid terminal can operate both in the 1xEV-DV system and in the 1xEV-DO system using time division multiplexing on one receiver. The hybrid terminal can maintain an active connection with the 1xEV-DO system to receive packet data services and control the paging channel in the 1xEV-DV system. This can be achieved by (1) temporarily stopping the 1xEV-DO connection before each allocated paging slot in the 1xEV-DV system, (2) setting the receiver to the 1xEV-DV system to receive the paging channel and (3) setting the receiver back to the 1xEV-system DO and reconnecting to 1xEV-DO after processing the 1xEV-DV paging channel. Since the connection with 1xEV-DO is based on asynchronous data packets, temporary stops and resumption of the 1xEV-DO connection are virtually invisible to users or applications running on the terminal. Using such techniques, the hybrid terminal can control the 1xEV-DO system with minimal impact on the control of the 1xEV-DV paging channel.

The above operation is described for the case when the hybrid terminal has already gained access to the 1xEV-DO system and has established active communication with the 1xEV-DO system. Traditionally, the terminal is not able to control the paging channel, trying to access the 1xEV-DO system. The reason for this is that the terminal must perform a sequence of time-critical tasks in order to gain access to the 1xEV-DO system, and tuning out the receiver to control the 1xEV-DV paging channel may interrupt this task sequence, as described below.

The terminal enters the 1xEV-DO access state and performs an access procedure to gain access to the 1xEV-DO system. For an access procedure, the terminal transmits one or more access probes to the 1xEV-DO system. The 1xEV-DO system responds with an access channel acknowledgment message (ACAck), which confirms the successful receipt of an access probe from the terminal. IS-856 defines the method by which access samples can be transmitted.

In IS-856, access samples are transmitted on an access channel to a 1xEV-DO system. The access channel is divided into access channel cycles, with each access channel cycle having a configurable duration of N _acd slots. Each slot has a duration of 1,667 milliseconds (ms) and is identified by the system time T _{sys_s} , which is set in the slots. Access channel cycles begin in slots in which T _{sys_s} mod N _acd = 0, where mod denotes a modulo operation. An access probe can only be transmitted starting with a new access channel cycle, but it can continue for one or many access channel cycles.

In IS-856, transmission is not allowed on the reverse link during designated silence intervals that occur periodically. Each silence interval has a configurable duration of N _SI frames. Each frame has a duration of 26.67 ms (or 16 slots) and is identified by the system time T _{sys_f} , which is set in frames. Silence intervals begin in frames in which T _{sys_f} mod (2048 × 2 ^Nsi -1) = 0.

FIG. 3 shows a timing diagram of accessing a 1xEV-DO system, which is called a timing pattern of access samples. The terminal can transmit up to N _s sequences of access probes to the 1xEV-DO system and can transmit up to N _p access probes for each sequence of access probes, where N _p and N _s are configurable parameters.

The terminal performs a stability test before starting the first sequence of access probes. The stability test is used to control congestion in the access channel. For stability tests, the terminal generates a pseudo-random number x between 0 and 1, compares x with the threshold q and announces successful completion if x is less than q, where q is a configurable parameter for each class of terminals. The terminal can start transmitting access samples if the stability test is successful or if 4 / q consecutive resistance tests fail.

After passing the stability test, the terminal transmits the first access probe in the access channel and then waits for the ACAck message from the 1xEV-DO system. If the ACAck message is not received, then the terminal waits for a random period of T _p slots, counting from the end of the previous access probe. This random waiting period T _{p is} also called the pause between samples and is calculated as follows. The terminal initially sets the variable y _total to zero. The terminal then generates a pseudo-random integer y, which is evenly distributed between 0 and N _pbo , where N _pbo is the maximum waiting period (in units of the duration of the access channel) between access probes. The terminal updates the variable y _total as y _total = y _total + y and then calculates a random waiting period T _p as follows:

(2)T _p = T _{ack_max} + y _total × N _acd ,

(2)

where T _{ack_max} is the maximum timeout for an ACAck message before transmitting another access probe. T _{ack_max} - 128 slots in IS-856.

The terminal then determines the time interval in which the second access probe will be transmitted. If this transmission interval of the sample overlaps with the interval of silence, the terminal transmits an access sample after the interval of silence. This is achieved by generating a new pseudo-random number y, adding this new y to the current y _total and calculating a new random waiting period T _p . The terminal continues to increase the waiting period until the transmission interval of the sample ceases to overlap with the interval of silence. The terminal then transmits a second access probe through T _p slots after the end of the first access probe.

The terminal transmits each subsequent access probe in the first sequence of access probes in the same manner, i.e. transmits an access probe, waits for an ACAck message, waits for a random period of time, and transmits another access probe. A terminal may transmit up to N _p access probes for a first sequence of access probes.

If the terminal transmits all N _p access samples for the first sequence of access samples and does not receive the ACAck message, then the terminal waits for a random period of time T _s slots before starting the second sequence of access samples. A random waiting period T _{s is} also called a pause between sequences, and it is calculated similarly as a random waiting period between samples T _p , except that the pseudo-random number y is evenly distributed between 0 and N _sbo , where N _sbo is the maximum waiting period between access probe sequences. The terminal then transmits a second access probe sequence in the same manner as the first access probe sequence. A terminal may transmit up to N _s access _probe sequences for an access procedure.

For the access procedure, the terminal continues to transmit access samples one at a time until either (1) the ACAck message is received from the 1xEV-DO system, or (2) the maximum number of access samples is transmitted. For the example shown in FIG. 3, the terminal receives the ACAck T _ack slots message after transmitting the third access probe in the second sequence of access probes. The terminal stops transmitting access samples after receiving this ACAck message. If the terminal sent the maximum number of access probe sequences and still did not receive the ACAck message within the T _{ack_max} slots after the last access probe, the terminal exits the access state to 1xEV-DO with a failure indication.

The access procedure described above indicates that the terminal performs a sequence of time-critical tasks during the time pattern of access samples. The terminal is not able to tune the receiver to control the 1xEV-DV paging channel without the possible violation of this time pattern of access samples. The terminal is not able to tune out to the 1xEV-DV system during allocated paging slots due to (1) the random nature of the waiting period T _p between samples and the waiting period T _s between sequences and (2) the asynchronous nature of the ACAck message from the 1xEV-DO system.

FIG. 4 shows the control of the 1xEV-DV paging channel and access to the 1xEV-DO system using a conventional hybrid terminal. This conventional terminal stops monitoring the 1xEV-DV paging channel before entering the 1xEV-DO access state at time t _a and resumes monitoring the 1xEV-DV paging channel after completing the access procedure and exiting the 1xEV-DO access state at time t _b . A typical terminal may skip paging messages when it is in a 1xEV-DO access state if the dedicated paging slot is between times T _a and T _b , as shown in FIG. four.

The timing diagram of access samples can be changed to enable the hybrid terminal to perform intra-system tasks by gaining access to the 1xEV-DO system. Such intra-system tasks may include monitoring the paging channel in another system (for example, in a 1xEV-DV system), performing pilot measurements, receiving signaling, or performing some other tasks at a different frequency and / or in another system, etc. Changing the timing diagram of access samples, as described below, minimally affects the operation of the hybrid terminal to access the 1xEV-DO system and is invisible to the 1xEV-DO system.

In an embodiment of the modified timing pattern of access samples, the terminal determines the total sample interval for the access sample to be sent to the 1xEV-DO system, as follows:

(3)

(3)

where T _ap is the transmission time of the access sample;

- предполагаемое время ответа для сообщения ACAck от системы 1xEV-DO для пробы доступа;

- the estimated response time for the ACAck message from the 1xEV-DO system for the access probe;

T _total - full sample interval.

можно устанавливать в значение между 96 и 128 слотами (т.е. 128>

>96) или в некоторое другое значение. Значение для

можно определять, основываясь на измерениях в условиях эксплуатации, компьютерном моделировании и т.д.As shown in equation (3), the full sample interval includes the transmission time of the access sample plus the estimated response time for the ACAck message from the 1xEV-DO system. IS-856 requires the base station to send an ACAck message within 96 access probe reception slots. IS-856 requires that the terminal wait at most 128 slots before transmitting another access probe. Estimated Response Time

can be set to a value between 96 and 128 slots (i.e. 128>

> 96) or some other value. Value for

can be determined based on measurements in the field, computer simulations, etc.

The terminal transmits the access sample so that the full sample interval does not overlap with the tuning interval, which is the time interval in which the terminal must configure the receiver to another system. The tune-away interval may correspond to a dedicated paging slot in a 1xEV-DV system, transmission of a pilot signal or signaling from another system, or some other event. The terminal transmits an access sample that begins in the cycle of the access channel, which meets the criterion for transmitting the sample, which requires that the full interval of the sample does not overlap with the offset interval. This start of the access channel cycle can be determined in various ways.

In the first access channel loop start determination scheme, the terminal first determines a random waiting period (if one exists) for the access probe in the usual manner, as defined by IS-856 and described above. The terminal then determines if any part of the full sample interval overlaps with the rebuild interval. If the answer is yes, then the terminal either delays or promotes the transfer of the access sample so that the full interval of the sample does not overlap with the rebuild interval.

For the first access probe in the first sequence of access probes, the terminal can transmit this access probe in the access channel loop immediately after the tune-off interval. For each subsequent access probe in the first sequence of access probes, the terminal can add N _a slots to a random waiting period T _p , where N _{a is} chosen so that the entire sample interval does not overlap with the offset interval. N _a may be the minimum number of slots that meets the criterion for transferring the sample. Alternatively, if T _p > T _{ack_max} + T _total , then the terminal can subtract N _b slots from a random waiting period T _p , where N _{b is} chosen so that the full sample interval does not overlap with the build-up interval. For the first access probe in each subsequent sequence of access probes, the terminal can add N _a slots to a random waiting period between sequences T _s or alternatively subtract N _b slots from T _s so that the full sample interval does not overlap with the build-up interval. Each subsequent access probe may be transmitted in the same manner.

FIG. 5 shows tunable access probe transmission. The terminal transmits the first access probe at time T ₁ and does not receive an ACAck message for this access probe. The terminal then determines a random waiting period T _{W of the} second access probe, where T _W may be either T _s or T _p . The terminal then determines the total sample interval T _total for the second access sample, as shown in equation (3). This full sample interval is between times T ₄ and T ₇ , where T ₄ -T _W slots from the end of the first access sample at time T ₂ . The terminal must rebuild between points in time T ₆ and T ₈ , which is the interval of rebuilding. Since the full sample interval overlaps with the offset interval between times T ₆ and T ₇ , the terminal can either delay or accelerate the transmission of the second access sample.

To delay the transmission of the second access probe, the terminal adds N _a slots to a random waiting period T _W , where N _{a is} chosen so that T ₂ + T _W + N _a > T ₈ . The waiting period then becomes T _wa = T _W + N _a . The terminal can rebuild to another system at time T ₆ , perform the necessary task, rebuild to the 1xEV-DO system at time T ₈ and transmit a second access probe at time T ₉ , which is located after time T ₈ .

To speed up the transmission of the second access probe, the terminal subtracts N _b slots from the random waiting period T _W , where N _{b is} chosen so that T ₂ + T _W -N _b + T _total <T ₆ . The terminal then transmits a second access probe at time point T ₃ , which is located T _W -N _b slots after the end of the first access probe and at least T _total before the start of the tune-off interval at time point T ₆ . The terminal ends the transmission of the second access probe and waits for an ACAck message at time T ₅ , which is located until time T ₆ . The terminal can then rebuild to another system at time T ₆ , perform the necessary task, and tune back to the 1xEV-DO system at time T ₈ .

In the second scheme, to determine the beginning of the access channel cycle, the terminal delays the transmission of the first access sample and determines a random waiting period for each subsequent access sample, taking into account the rebuild interval in a similar way as the silence interval. For the first access probe in the first sequence of access probes, the terminal can transmit this access probe that starts in the access channel cycle immediately after any silence interval and any tune-off interval. For each subsequent access probe in the first sequence of access probes, the terminal generates a pseudo-random number y and calculates a random waiting period T _p , as shown in equation (2). The terminal then determines whether (1) the sample transmission interval overlaps with the silence interval and (2) the full sample interval overlaps with the rebuild interval. If either condition (1) or condition (2) is true, then the terminal generates a new pseudo-random number y, adds this new y to the current y _total and calculates a new random waiting period T _p . The terminal continues to increase the waiting period T _p until (a) the transmission interval of the sample ceases to overlap with the interval of silence and (b) the full interval of the sample ceases to overlap with the interval of detuning. The terminal then transmits the next access probe T _p slots after the end of the previous access probe.

The terminal calculates a random waiting period T _s between sequences of access probes in the same manner. The terminal continues to increase the waiting period T _s until (a) the transmission interval of the sample ceases to overlap with the interval of silence and (b) the full interval of the sample ceases to overlap with the interval of detuning. The terminal then transmits the first access probe in a new sequence of T _s slots from the end of the last access probe in the previous sequence.

The second scheme leads to a delayed transmission of the access sample if the full sample interval overlaps with the rebuild interval. However, the access probe is transmitted starting from the access channel cycle, which is located on a pseudo-random number of slots from the end of the tune-away interval, instead of the access channel cycle located immediately after the end of the tune-away interval.

FIG. 6 shows an example of gaining access to a 1xEV-DO system and controlling a 1xEV-DV paging channel using a hybrid terminal with a modified time pattern of access samples. In the first sequence of access probes, the terminal transmits the first and second access probes in the usual way and does not receive the ACAck message. For a third access sample, the terminal determines a random waiting period T _p and a full sample interval, determines that the full sample interval overlaps with the rebuild interval, and therefore delays the transmission of the third access sample to N _a slots. The transmission of the access sample without delay is indicated by the dashed line of the frame in FIG. 6. The transmission delay of the third access probe allows the terminal to tune out to control the 1xEV-DV paging channel. A subsequent access probe is transmitted in the usual manner without the need to delay any of these access probes.

As shown in FIG. 6, the modified access probe timing diagram allows the terminal to tune out and control another system with a short interruption of the access procedure. Without the ability to rebuild, the terminal could not control the 1xEV-DV paging channel during access to the 1xEV-DO system and could skip paging messages. The ability to tune can significantly reduce the proportion of missed calls due to access to the 1xEV-DO system.

For the embodiment described above, an access sample is transmitted so that the full sample interval does not overlap with any part of the setback interval. This limitation can be relaxed if the terminal does not need to transmit to the 1xEV-DV system and it only needs to divide the receiver time division between monitoring the 1xEV-DV system with respect to paging messages and the 1xEV-DO system with respect to the ACAck message.

In another embodiment of the modified timing pattern of access samples, the terminal transmits the access sample so that the expected response time does not overlap with the tune-away interval. For this embodiment, the sample transfer time may overlap the tune-off interval since the terminal can transmit to the 1xEV-DO system and simultaneously receive from the 1xEV-DV system. For the delayed transmission example of the access probe shown in FIG. 5, a second access probe can be transmitted starting earlier than time T ₈ and ending at or after time T ₉ .

In the above description, the terminal delays or speeds up the transmission of the access sample if the full sample interval (or the expected response time) overlaps with the tune-off interval. The terminal may also terminate the access procedure and exit the access state to 1xEV-DO if the rebuild interval exceeds a predetermined duration (for example, 500 ms). The terminal may provide an indication of failure when exiting the access state to 1xEV-DO.

FIG. 7 shows a process 700 performed by a hybrid terminal to access a rebuildable 1xEV-DO system. Process 700 is for an embodiment in which the terminal delays or accelerates the transmission of the access sample so that the full sample interval does not overlap with the offset interval.

First, the terminal sets the variable s for the current sequence of access probes to unity and the variable p for the current access probe to unity (step 710). Before starting a new sequence of access probes, the terminal performs a stability test (block 712). It then determines whether (1) the stability test completed successfully and (2) whether the number of consecutive failed stability tests exceeds 4 / q (step 714). If both conditions are false and the answer is no at step 714, then the terminal returns to step 712 to perform another stability test. Otherwise, if any of the conditions is true and the answer is “yes” at step 714, then the terminal proceeds to step 720 and starts a new sequence of access probes.

слотов от конца пробы доступа, то определяют, послали ли максимальное количество проб доступа для текущей последовательности проб доступа, т.е. p=N_p (этап 730). Если ответ - «нет», то переменную p увеличивают (этап 732). Терминал затем определяет случайный период ожидания между пробами T_p и ждет этот период времени (этап 734). Терминал затем возвращается на этап 720 для передачи новой пробы доступа для текущей последовательности проб доступа.Before transmitting a new access sample, the terminal determines the start of the access channel cycle for transmitting the access sample so that the full sample interval does not overlap with the offset interval (step 720). This start of the access channel cycle can be determined based on the first or second pattern described above, or in some other way. The terminal then transmits a new access probe at the start of the access channel cycle (block 722). After transmitting the access probe, the terminal waits for the ACAck message. If the ACAck message is received, as determined at step 724, then the terminal ends the access procedure with an indication of success (step 726). Otherwise, if the ACAck message is not received after

slots from the end of the access probe, it is determined whether the maximum number of access probes for the current sequence of access probes has been sent, i.e. p = N _p (step 730). If the answer is “no”, then the variable p is increased (step 732). The terminal then determines a random waiting period between samples T _p and waits for this period of time (block 734). The terminal then returns to step 720 to transmit a new access sample for the current sequence of access samples.

If the maximum number of access samples was sent for the current sequence of access samples, and the answer is “yes” at step 730, then it is determined whether the maximum number of sequences of access samples was sent, i.e. s = N _s (block 740). If the answer is “no”, then the variable s is increased (step 742). The terminal then determines a random waiting period between sequences T _s and waits for this period of time (block 744). The terminal then returns to block 712 to perform a stability test before initiating a new sequence of access probes. Returning to step 740, if the maximum number of access probe sequences was sent and the answer is “yes,” then the terminal ends the access procedure with an indication of failure (step 746).

For clarity, rebuilding access techniques have been described specifically for 1xEV-DV and 1xEV-DO systems. These techniques can be used for other radio communication systems, such as, for example, a W-CDMA system, a GSM system, a wireless local area network (WLAN), such as an IEEE 802.11 network, an orthogonal frequency division multiple access (OFDMA) system, etc. These techniques allow the terminal to access the system by completing tasks for one or more other systems. For example, the terminal can access the 1xEV-DO system by monitoring the paging channel in the 1xEV-DV system, by measuring the pilot signal in the W-CDMA system and / or in the GSM system, etc.

FIG. 8 shows a process 800 performed by a hybrid terminal to gain access to a first communication system (e.g., 1xEV-DO system) with the ability to tune away to a second communication system (e.g., 1xEV-DV system). The terminal determines a transmission time point for the access probe to be sent to the first system (step 810), and the expected response time for confirmation from the first system for the access probe (step 812). The terminal then determines a secure time interval for the access probe based on the transmission time and / or the expected response time (step 814). The protected time interval is the time interval in which the receiver is tuned to the first system, and it can be between (1) the expected response time and (2) the transmission time plus the expected response time.

The terminal then determines the start time for transmitting the access sample so that the protected time interval does not overlap with the tune-away interval (block 816). This trigger time can be set initially at the end of the previous access probe plus a pseudo-random waiting period. This trigger time can be advanced or moved backward in time, if necessary, for a time period selected so that the protected time interval does not overlap with the offset interval. The terminal then transmits a sample access to the first system at the time of startup (step 818). The terminal returns to block 810 if another access probe needs to be sent, as determined at block 820, otherwise terminates the process.

FIG. 9 shows a block diagram of an embodiment of a hybrid terminal 130. Terminal 130 includes a wireless modem for communicating with multiple systems (eg, 1xEV-DV and 1xEV-DO systems), a controller 940, a memory 942, and a timer 944. In the transmission path, data and signaling for transmission by terminal 130, it is processed (e.g., formatted, encoded, and interleaved) using an encoder 922 and further processed (e.g., modulated, spread spectrum, structured, and scrambled) using a modulator (Mod) 924 to generate a data signal stream. The transmitter module (Rx) 932 brings to the required state (for example, converts to an analog signal, filters, amplifies and converts with increasing frequency) the data signal stream to generate a signal of the reverse communication channel, which is transmitted through the antenna 936. In the receiving path, the signals of the forward communication channel transmitted by the base stations in the systems are received using the antenna 936 and provided to the receiver module (PFP) 938. The receiver module 938 brings to the required state (for example, filters, amplifies, converts with decreasing frequency and digitally received signal to generate a data sample. A demodulator (Demod) 926 processes (e.g., descrambles, compresses the spectrum, structures, and demodulates) data samples to obtain a symbol estimate. Decoder 928 further processes (e.g., interleaves and decodes back) symbol estimates to obtain decoded data. Encoder 922, modulator 924, demodulator 926, and decoder 928 can be implemented using modem processor 920 and can be provided on one special integrated circuit (LIS) along with, for example, controller 940, memory 942, and timer 942. These modules perform processing as defined systems.

A controller 940 controls the operation of various modules within terminal 130. A memory unit 942 stores program codes and data used by the controller 940 and other modules. A timer 944 provides synchronization information used to determine when to transmit an access probe to one system (e.g., 1xEV-DO system) and when to tune in to another system (e.g., 1xEV-DV system). Controller 940 may carry out process 700 in FIG. 7 to gain access to the 1xEV-DO system by monitoring the 1xEV-DV system, or the process 800 shown in FIG. 8.

The described access techniques with the ability to rebuild can be carried out using various means. For example, these techniques may be embodied in hardware, software, or a combination thereof. For implementation in equipment, processors used to gain access to one system, to control another system, etc. can be implemented within one or more specialized integrated circuits, digital signal processing (DSP) processors, digital signal processing devices (DSPD) , programmable logic devices (PLDs), user-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, electronic devices, and other electronic modules that assigned to perform the described functions, or combinations thereof.

For a software implementation, retuning access techniques can be implemented using modules (e.g., procedures, functions, etc.) that perform the described functions. Software codes may be stored in a memory unit (for example, in a memory unit 942 in FIG. 9) and executed by a processor (eg, controller 940). The memory unit may be implemented within the processor or outside the processor.

Various modifications of the described embodiments will be readily apparent to those skilled in the art, and the general principles defined in this work can be applied to other embodiments without departing from the scope or form of the invention.

Claims (29)

1. A device for accessing a wireless communication system configured to tune away, comprising a controller configured to determine a secure time interval when the access request can be transmitted to the first communication system, determine a start time for transmitting the access request so that the secure time interval is not overlapped with the interval of rebuilding, and initiating the transmission of a request for access to the first communication system at a given start time. 2. The device according to claim 1, additionally containing a receiver, in which the protected time interval is a time interval in which the receiver is tuned to the first communication system, and in which the tuning interval is the time interval in which the receiver is detached from the first communication system. 3. The device according to claim 1, in which the controller is further configured to determine the expected response time to confirm the access request from the first communication system and determine a secure time interval based on the expected response time. 4. The device according to claim 1, in which the controller is further configured to determine a transmission time for an access request, determining a secure time interval, further based on the transmission time. 5. The device according to claim 1, wherein the controller is further configured to determine an initial time for transmitting an access request and setting a start time at an initial time plus or minus a zero or non-zero time period selected such that transmitting an access request at a start time leads so that the protected time interval does not overlap with the rebuild interval. 6. The device according to claim 5, in which the controller is further configured to determine a pseudo-random waiting period and set the initial time at the end of a previous access request plus a pseudo-random waiting period. 7. The device according to claim 1, in which the controller is additionally configured to initially set the start time to the end of the previous access request, to determine the pseudo-random waiting period, to advance the start time to the pseudo-random waiting period, and to re-define the pseudo-random waiting and moving periods forward of the start time until the transmission of the access request at the time of the start leads to the fact that the protected time interval does not overlap with and otstraivaniya interval. 8. The device according to claim 2, in which the controller is further configured to instruct the receiver to tune to the second communication system before the tune-off interval, and to instruct the receiver to tune back to the first communication system after the tune-off interval. 9. The device of claim 8, in which the controller is further configured to receive a paging channel from the second communication system during the rebuild interval. 10. The device according to claim 1, in which the rebuild interval corresponds to a dedicated paging slot for the second communication system. 11. The device according to claim 1, in which the offset interval corresponds to the transmission of the pilot signal or the transmission of signaling from the second communication system. 12. The device according to claim 1, in which the rebuild interval corresponds to the measurement interval for the second communication system. 13. A method of accessing a wireless communication system configured to tune away, comprising the steps of:
determining a secure time interval for an access request to be sent to the first communication system, a secure time interval is a time interval in which the receiver is tuned to the first communication system;
determining a start time point for transmitting an access request so that the protected time interval does not overlap with the tune-away interval, the tune-off interval is the time interval in which the receiver is detached from the first communication system; and
transmit an access request to the first communication system at a given start time. 14. The method of claim 13, wherein defining a secure time interval for an access request comprises the steps of: determining a transmission time for an access request, determining an expected response time for confirming an access request from the first communication system, and determining a secure time interval based on at least one of the transmission time and the expected response time. 15. The method of claim 13, wherein determining a start time for transmitting an access request comprises the steps of: determining a pseudo-random waiting period, setting a start time to the end of the previous access request plus a pseudo-random waiting period, and adjusting the start time either forward or backward in time , if necessary, for a period of time selected so that the transmission of the access request at the corrected start time leads to the fact that the protected time interval does not overlap with the rebuild interval . 16. The method according to item 13, further comprising the steps of: tuning the receiver to a second communication system before the rebuild interval;
receive a paging channel from the second communication system and tune the receiver back to the first communication system after the rebuild interval. 17. A device for accessing a wireless communication system configured to rebuild, comprising:
means for determining a secure time interval for an access request to be sent to the first communication system, the secure time interval is the time interval in which the receiver is tuned to the first communication system; means for determining a start time for transmitting an access request so that the protected time interval does not overlap with the tune-away interval, the tune-off interval is the time interval in which the receiver is detached from the first communication system; and means for transmitting an access request to the first communication system at a start time. 18. The device according to 17, in which the means for determining a secure time interval for an access request comprises means for determining a transmission time for an access request, means for determining an expected response time for confirming an access request from the first communication system, and means for determining a secure time interval based on the transmission time and the expected response time. 19. The device according to 17, in which the means for determining the start time for transmitting the access request includes means for determining the pseudo-random waiting period, means for setting the start time to the end of the previous access request plus the pseudo-random waiting period, and means for adjusting the start time either forward or backward in time, if necessary, for a period of time selected so that the transmission of the access request at the adjusted start time leads to the fact that it is protected the first time interval does not overlap with otstraivaniya interval. 20. The device according to 17, additionally containing means for tuning the receiver to the second communication system before the rebuild interval; means for receiving a paging channel from the second communication system; and means for tuning the receiver back to the first communication system after the tuning interval. 21. A computer-readable medium comprising computer-executable instructions for causing a processor in a wireless device to perform the steps of determining a secure time interval for an access request to be sent to the first communication system, a secure time interval is the time interval in which the receiver is tuned to the first system communication;
determining a start time point for transmitting an access request so that the protected time interval does not overlap with the tune-away interval, the tune-off interval is the time interval in which the receiver is detached from the first communication system; and are prompted to transmit an access request to the first communication system at a given start time. 22. The computer-readable medium of claim 21, further comprising instructions for determining a transmission time for an access request; determining the expected response time to confirm the access request from the first communication system and determining a secure time interval based on the transmission time and the expected response time. 23. The computer-readable medium of claim 21, further comprising instructions for determining a pseudo-random waiting period; setting the start time to the end of the previous access request plus a pseudo-random waiting period and adjusting the start time either forward or backward in time, if necessary, for the time period chosen so that the transmission of the access request at the adjusted start time leads to the protected time interval did not overlap with the rebuild interval. 24. The computer-readable medium of claim 21, further comprising instructions for causing the receiver to tune to the second communication system before the tune-off interval;
the motivation for receiving a paging channel from a second communication system and
prompting the receiver to tune back to the first communication system after the setback interval. 25. A method of accessing a system, comprising the steps of: determining a secure time interval for an access request to be sent to a communication system intended only for data transmission, a secure time interval is a time interval in which the receiver is tuned to a system intended only for data transmission ; determining the start of the access channel cycle for transmitting the access request so that the protected time interval does not overlap with the tune-off interval, the tune-off interval is the time interval in which the receiver is tuned to the voice and data communication system; and transmitting an access request to a communication system intended only for data transmission at the beginning of an access channel cycle. 26. The method of claim 25, wherein determining a secure time interval for an access request comprises determining a transmission time for an access request, determining an expected response time for confirming an access request from a data-only system, and setting a secure time interval based on transmission time and expected response time. 27. The method according A.25, in which determining the start of an access channel cycle for transmitting an access request comprises the steps of: determining a pseudo-random waiting period, setting the start of an access channel cycle to a first access channel cycle located immediately after the previous access request plus a pseudo-random waiting period and select the second cycle of the access channel as the start of the cycle of the access channel, if the transmission of the access request in the first cycle of the access channel leads to the fact that the protected time interval overlaps I otstraivaniya interval. 28. The method according to item 27, in which the second cycle of the access channel is located after the first cycle of the access channel. 29. The method according A.25, further comprising the steps of: setting up the receiver to a data and voice transmission system before the rebuild interval; receive a paging channel from the data and voice transmission system and tune the receiver back to the data transmission system only after the tuning interval.

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