WO2011008060A2

WO2011008060A2 - Method for user pairing test

Info

Publication number: WO2011008060A2
Application number: PCT/KR2010/004705
Authority: WO
Inventors: Haipeng Lei; Xiaoqiang Li
Original assignee: Samsung Electronics Co., Ltd.; Beijing Samsung Telecom R&D Center
Priority date: 2009-07-17
Filing date: 2010-07-19
Publication date: 2011-01-20
Also published as: WO2011008060A3; KR20110007990A; CN101959305A

Abstract

An embodiment of the present invention provides a method for user pairing test, applicable to a GERAN/VAMOS system. In the method, a time condition for stress test is preset and a base station selects two users as candidate users. Then, when the time condition for the stress test is satisfied, the base station instructs one of the candidate users to perform the stress test on a slot of the other candidate user and to report a channel condition. Next, the base station adjusts transmission power of the two candidate users according to channel conditions reported by the two candidate users, and when channel qualities of the candidate users meet channel quality requirements, multiplex the two candidate users onto a same time-frequency resource and releases redundant time-frequency resources. Another embodiment of the present invention provides another method for user pairing test. According to the methods, mobile stations of users are not required to support multi-slot processing and no additional slot is required. The user pairing test can still be realized, the system capacity is increased and the system call drop probability is reduced.

Description

METHOD FOR USER PAIRING TEST

The present invention relates to wireless communication technologies, and more particularly, to a method for user pairing test applicable to a GERAN/VAMOS system.

In recent years, with a rapid increase in requirements of mobile voice services, the GSM network receives rapid development. Consequently, it becomes more and more difficult for limited spectrum resources to meet people’s communication requirements, especially in populous cities. In addition, with an increase in the aging degree of GSM network devices, it becomes quite urgent to expand capacities of the GSM network. However, from the aspect of an operator, because charges for the voice services are reduced gradually year by year, it is required to reuse existing hardware resources and frequency resources more effectively. Therefore, it becomes a quite important research field to improve system capacities on the premise that the existing system frequency resources are not increased.

The Multiple User Reuse One Slot (MUROS) technique is mainly applied to 3GPP GSM/EDGE Radio Access Network (GERAN). The MUROS technique is named Voice services over Adaptive Multi-user channels on One Slot (VAMOS) formally in the GERAN#40 meeting in November in 2008.

The GERAN/VAMOS system needs to further improve voice capacities on the basis of reusing the existing network devices and wireless resources. At a feasibility study stage, a candidate VAMOS solution mainly multiplexes two or more users onto one slot on the premise that the communication quality is not decreased. At present, the industry mainly considers improving the system voice capacities by twice, i.e. reusing two users on each slot. On one aspect, what affected by this solution are full-rate and half-rate voice channels, including: TCH/FS, TCH/HS, TCH/EFS, TCH/AFS, TCH/AHS and TCH/WFS, as well as related associated control channels such as a Slow Associated Control Channel (SACCH) and a Fast Associated Control Channel (FACCH). On the other aspect, after the VAMOS technique is used, along with an increase in the number of users in a cell, it will definitely cause an increase in common frequency interference and adjacent frequency interference and also will result in a decrease in a Carrier/Interference (C/I) ratio and frequency multiplexing. Therefore, how to reach a compromise between reducing frequency multiplexing and increasing slot reuse should be further studied.

Conventional candidate VAMOS solutions mainly include the following three kinds:

First, Co-Traffic-Channel (Co-TCH) solution

On the downlink, two channels of Gauss Minimum Frequency-shift Keying (GMSK) baseband modulation signals are combined linearly, and are then transmitted after frequency modulation and power amplification. The two channels of signals have a π/2 phase difference.

On the uplink, each Mobile Station (MS) adopts GMSK modulation, adopts a Training Sequence (TSC) different from any other, and separates two channels of multiplexed user signals at a bases station side according to a method such as associated detection.

Second, Orthogonal Sub-channel (OSC) solution

On the downlink, Quarternary Phase-Shift Keying (QPSK) is adopted to transmit two channels of user signals; and at a user receiving end, each channel of user signals may be received through the GMSK modulation.

On the uplink, each mobile station adopts the GMSK modulation, adopts a training sequence different from any other, and separates two channels of multiplexed user signals at the bases station side according to a method such as interference cancellation.

Third, Adaptive Symbol Constellation mapping (ASC) solution

On the downlink, an alpha-QPSK solution is adopted, and transmission power of I channel and Q channel can be controlled through adaptively adjusting constellation mapping.

On the uplink, each mobile station adopts the GMSK modulation, adopts a training sequence different from any other, and demodulates two channels of multiplexed user signals at the bases station side by using a Multi-User-Multiple-Input Multiple-Output (MU-MIMO) receiver.

Although the above three solutions have differences, they can all be deemed that two sub-channels, sub-channel 1 and sub-channel 2, share a same time-frequency resource. Generally, the sub-channel 1 can support earlier cell phones and the sub-channel 2 can only support cell phones with the VAMOS technique, called VAMOS cell phones for short.

Figure 1 is a schematic diagram illustrating a frame structure of a conventional GSM system. As shown in Figure 1, the GSM system adopts Time Division Multiple Access (TDMA) technique. Each TDMA frame is divided into 8 slots, which are numbered 0, 1, …, 7. Regardless of frames or slots, they are not overlapped with each other. A slot is a basic wireless resource unit in the GSM system. According to a specific slot allocation principle, in each frame, each mobile station can transmit a signal to the base station only on a designated slot; and in a periodical and synchronizing condition, the base station can receive the signal of each mobile station on each respective slot without confusion and interference of signals. Meanwhile, signals transmitted by the base station to multiple mobile stations are arranged in sequence, and are transmitted on predetermined slots. As long as each mobile station receives the signals on a designated slot, it can differentiate a signal transmitted to itself from the combined signals.

Figure 2 is a schematic diagram illustrating two users reusing one time-frequency resource in the conventional GERAN/VAMOS system. In the circuit switch mode, the VAMOS allows multiplexing two users onto one time-frequency resource. These two users form one VAMOS pair, and share a same slot number, ARFCN and TDMA frame number on the uplink and the downlink.

Figure 3 is a schematic diagram illustrating downlink modulation of users in a pair in the conventional GERAN/VAMOS system. The VAMOS sub-channel 1 and the VOMOS sub-channel 2 in Figure 3 are voice Traffic Channels (TCH) of two users respectively in a VAMOS pair. Bits of the VAMOS sub-channel 1, the VOMOS sub-channel 2 and the corresponding associated control channel are mapped onto one Adaptive QPSK (AQPSK) modulation symbol (Si shown in Figure 3). After performing rotation and pulse shaping on the Si, the Si is then transmitted. At the receiving end, a user demodulates its own bits on the TCH and the corresponding associated control channel, and performs wireless link measurement.

Figure 4 is a schematic diagram illustrating uplink modulation of users in a pair in the conventional GERAN/VAMOS system. On the uplink, two users in a pair in one cell adopt the GMSK modulation and transmit signals on a same time-frequency resource, i.e. the two users have a same slot number, and ARFCN and TDMA frame number. Users are differentiated according to different training sequences in data transmitted by the users. In one cell, users on two sub-channels adopt training sequences in different TSC sets. For example, a user on the sub-channel 1 adopts a training sequence in TSC set 1, and a user on the sub-channel 2 adopts a training sequence in TSC set 2. At the base station receiving end, the multi-user detection or interference cancellation technique is adopted to demodulate and decode the received signals of the two users, and meanwhile corresponding wireless link control is performed on the two users respectively.

Although the foregoing three conventional candidate VAMOS solutions ensure orthogonality between the two multiplexed users, the inter-symbol interference caused by the multipath propagation characteristic of wireless channels plus the nonlinear characteristic of a transmitting filter and a receiving filter will cause crosstalk between two sub-channels at the receiving end. On the downlink, this means that two multiplexed users interfere with each other. On the uplink, this means that a random phase difference between the users causes that the orthogonality at the receiving end can not be ensured even when the channels do not have time-diffusibility attenuation. Because the orthogonality between two sub-channels can not be ensured at the receiving end, intra-cell interference is generated and two multiplexed sub-channels interfere with each other, which causes a decrease in the system performance. After the system matches two users together, due to the interference between the sub-channels, it is impossible to ensure that the wireless channel transmission quality of each user is acceptable, neither to quickly change channel conditions of users through adjusting transmission power of the users in a pair. In this situation, call drop of users usually occurs and the service quality thus decreases.

Based on the above situation, currently, users with good channel conditions and high signal-noise ratios are mainly selected as candidate users in a pair. Meanwhile, the transmission power of the selected users is increased so as to ensure that the users after being in a pair still have an acceptable channel quality. Regarding the so call acceptable channel quality, the channel quality of a user is divided into 8 levels according to the GSM, different levels representing different channel qualities. When a channel quality is not lower than a level used as a threshold, the channel quality is deemed as the acceptable channel quality. Even so, the user pairing still has a huge uncertainty. For example, if initial transmission power of a user is insufficient or the transmission power can not be quickly adjusted to a continuous-satisfying channel condition, it will cause call drop or cause returning to a mode that a single user occupies one slot from the VAMOS multiplexing mode.

In addition, different users encounter different interference degrees at different positions, different slots or different frequencies, and also encounter different inter-sub-channel interference after the user pairing. Therefore, it becomes quite difficult to predict an interference situation.

In a Frequency Division Duplex (FDD) system, the uplink and the downlink are in different channel conditions. Especially after the VAMOS multiplexing is introduced, the downlink adopts the AQPSK modulation while the uplink keeps adopting the GMSK modulation, which makes the uplink and the downlink encounter different interference. On the uplink, the base station needs to determine the initial transmission power after the user pairing. Thus, it is determined that both the uplink and the downlink require stress test.

In view of the above, before the system decides to match two users on a same time-frequency resource, it requires pairing test first, i.e. enabling mobile stations of two candidate users to transmit or receive dummy data and performing the pairing test in the stress test mode. Meanwhile, it requires adjusting transmission power ratios of mobile stations of the two users so that the two users in a pair still have relatively reliable channel transmission qualities, thereby reducing a call drop probability. If both the uplink and the downlink can satisfy the channel transmission qualities of the two users in a pair, the pairing test is completed, the two users are multiplexed onto a same time-frequency resource and redundant wireless resources are released.

A familiar conventional method for pairing test is that the base station assigns one dedicated slot to the two candidate users for the stress test. On the dedicated slot, the mobile stations of the two candidate users transmit or receive the dummy data and submit channel measurement reports; meanwhile, original slots of the two users are still reserved to be used for transmitting or receiving practical communication data of the two users. The method has disadvantages: the method requires not only one extra slot for the stress test but also requires that all mobile stations of candidate users must support the multi-slot processing capability, and therefore the method has a quite limited application scope in a practical system.

Another conventional method for pairing test is that: the base station takes a slot of any of the two candidate users as the slot for the stress test. On the slot for the stress test, the mobile stations of the candidate users transmit or receive the dummy data and submit channel measurement reports, while the original slot of the other user is still reserved to be used for transmitting or receiving the practical communication data of the other user. This method does not need an extra slot for the stress test. However, this method still requires that the mobile stations of the candidate users support multi-slot processing capability, and thereby its application scope is restricted.

In view of the above, an objective of the present invention is to provide a method for user pairing test, which does not require mobile stations of users support multi-slot processing and implements the user pairing test on a condition that no extra slot is required, thereby improving a system capacity and reducing a system call drop probability.

To achieve the above objective, a technical scheme of the present invention is implemented as follows:

A method for user pairing test, applicable to a Voice services over Adaptive Multi-user channels on One Slot (VAMOS) system in which multiple users are multiplexed onto a same slot, includes presetting a time condition for stress test, and further includes steps of:

A, selecting, by a base station, two users including a first user and a second user as candidate users;

B, instructing, by the base station, the second user to perform the stress test on a slot of the first user;

C, when the time condition for the stress test is satisfied, performing, by the second user, the stress test on the slot of the first user, and reporting a channel condition to the base station;

D, determining, by the base station according to channel conditions reported by the first user and the second user, whether channel qualities of the first user and the second user meet preset channel quality requirements; if the channel qualities of the first user and the second user meet the preset channel quality requirements, proceeding to step F; otherwise, proceeding to step E;

E, adjusting, by the base station according to the channel conditions reported by the first user and the second user, transmission power of the first user and the second user; and returning to the step C; and

F, multiplexing, by the base station, the first user and the second user onto a same time-frequency resource, and releasing time-frequency resources occupied by the first user and the second user except the time-frequency resource multiplexed.

Preferably, the time condition for the stress test is that the second user is in a Discontinuous Transmission (DTX) state and that the second user need not transmit a Silence Indicator and a Slow Associated Control Channel (SACCH) in a current frame

Preferably, the time condition for the stress test is that the second user requests a voice Traffic Channel (TCH).

The step A may include: selecting, by the base station, two users as the candidate users randomly; or selecting, by the base station according to channel qualities of users, two users with similar channel qualities as the candidate users

The step B includes: determining, by the base station, whether mobile stations of the two users both support VAMOS; if the mobile stations of the two users both support the VAMOS, selecting any of the two users as the second user; otherwise, selecting a user corresponding to a mobile station which does not support the VAMOS as the second user

When the time condition for the stress test is that the second user requests the TCH, a mobile station of the second user support VAMOS.

In the step B, instructing by the base station the second user to perform the stress test on the slot of the first user includes:

instructing, by the base station, a candidate user to perform the stress test through an assignment command;

including the slot of the first user and a Mobile Allocation Index Offset (MAIO), or the slot of the first user and an Absolute Radio Frequency Channel Number (ARFCN) into the assignment command; and

notifying the second user to report the channel condition.

Preferably, an idle bit or an idle bit combination in a channel type and Time Division Multiple Access (TDMA) offset field in a channel description message of the assignment command is taken as an indicator for indicating the candidate user whether the stress test should be performed; and

the slot of the first user and the MAIO, or the slot of the first user and the ARFCN are included into the channel description message of the assignment command.

When the time condition for the stress test is that the second user is in the DTX state and the second user need not transmit the SID and the SACCH in the current frame, the assignment command is transmitted to the second user through a Fast Associated Control Channel (FACCH);

when the time condition for the stress test is that the second user requests the TCH, the assignment command is transmitted to the second user through a Stand-Alone Dedicated Control Channel (SDCCH)

Preferably, performing the stress test on the slot of the first user by the second user in the step C includes:

through a sub-channel 2 of the first user, transmitting dummy data, or receiving the dummy data, or receiving and transmitting the dummy data by the second user by using a training sequence in a training sequence set different from a training sequence set which a training sequence used by the first user belongs to.

Preferably, the preset channel quality requirements are that channel conditions of uplinks and downlinks of the two candidate users all reach a preset channel quality threshold, or that channel conditions of the downlinks of the two candidate users reach the preset channel quality threshold, or that channel conditions of the uplinks of the two candidate users reach the preset channel quality threshold.

a, selecting, by a base station, candidate users;

b, instructing, by the base station, the candidate users to perform the stress test on respective slots of the candidate users;

c, when the time condition for the stress test is not satisfied, transmitting, by the base station, voice data of each candidate user through a sub-channel 1 of the candidate user, and transmitting dummy data through a sub-channel 2; when the time condition for the stress test is satisfied, transmitting, by the base station, the dummy data through both the sub-channel 1 and the sub-channel 2 of each candidate user; receiving, by each candidate user, data through the sub-channel 1 of a slot of the candidate user, and reporting a channel condition to the base station;

d, determining, by the base station according to the channel condition reported by each candidate user, whether a channel quality of the candidate user meet a preset channel quality requirement; if the channel quality of each candidate user meet the preset channel quality requirement, proceeding to step f; otherwise, proceeding to step e;

e, adjusting, by the base station according to the channel condition reported by each candidate user, transmission power of the sub-channel 1 and the sub-channel 2 of each candidate user; and returning to the step c;

f, multiplexing, by the base station, candidate users whose channel qualities meeting the preset channel quality requirement onto a same time-frequency resource, and releasing time-frequency resources occupied by the candidate users except the time-frequency resource multiplexed.

Preferably, the time condition for the stress test is that the candidate users are in a Discontinuous Transmission (DTX) state and that the candidate users need not transmit a Silence Indicator and a Slow Associated Control Channel (SACCH) in a current frame.

Preferably, the candidate users selected in the step a are two, a first user and a second user;

the step d includes: determining, by the base station according to channel conditions reported by the first user and the second user, whether channel qualities of the first user and the second user meet preset channel quality requirements; if the channel qualities of the first user and the second user meet the preset channel quality requirements, proceeding to the step f; otherwise, proceeding to the step e;

the step e includes: adjusting, by the base station according to the channel conditions reported by the first user and the second user, the transmission power of the sub-channel 1 and the sub-channel 2 of the first user and the second user; and returning to the step c; and

the step f includes: multiplexing, by the base station, the first user and the second user onto the same time-frequency resource, and releasing time-frequency resources occupied by the first user and the second user except the time-frequency resource multiplexed.

Preferably, the candidate users selected in the step a are more than two;

the step d includes: determining, by the base station according to channel conditions reported by the candidate users, whether there is a candidate user whose channel quality meets the preset channel quality requirement; if there is the candidate user whose channel quality meets the preset channel quality requirement, terminating the stress test for the candidate user and proceeding to the step f; otherwise, proceeding to the step e for a candidate user for which the stress test is not terminated;

the step e includes: adjusting, by the base station according to the channel conditions reported by the candidate users, the transmission power of the sub-channel 1 and the sub-channel 2 of each corresponding candidate user; and returning to the step c; and

the step f includes: determining whether candidate users for which the stress test is terminated but user pairing is not completed include two candidate users whose channel qualities meet preset channel quality requirements; if including the two candidate users, multiplexing the two candidate users onto the same time-frequency resource, releasing time-frequency resources occupied by the two candidate users except the time-frequency resource multiplexed, terminating the user pairing for the two candidate users, and determining whether there is a candidate user whose channel quality does not meet the preset channel quality requirement; if there is a candidate user whose channel quality does not meet the preset channel quality requirement, performing the step e for a candidate user for which the stress test is not terminated.

Preferably, the step a includes:

selecting, by the base station, users as the candidate users randomly; or selecting, by the base station according to channel qualities of users, users with similar channel qualities as the candidate users.

Preferably, instructing by the base station the candidate users to perform the stress test on the respective slots of the candidate users in the step b includes:

taking an idle bit or an idle bit combination in a channel type and Time Division Multiple Access (TDMA) offset field in a channel description message of an assignment command as an indicator for indicating the candidate users whether the stress test should be performed;

instructing the candidate users to perform the stress test through the assignment command and to report the channel conditions; and

transmitting the assignment command through a Fast-Associated Control Channel (FACCH).

As can be seen from the above technical scheme of the present invention, in the method for user pairing test according to the present invention, the time condition for stress test is preset; then, the base station notifies a candidate user to perform the stress test on a slot of the candidate user or a slot of another candidate user when the time condition for the stress test is satisfied, and to report a channel condition; finally, the base station adjusts transmission power of candidate users according to channel conditions of the candidate users, and when channel qualities of the candidate users meet the channel quality requirements, multiplexes two candidate users onto a same time-frequency resource and releases redundant time-frequency resources. According to the method in this embodiment, on one aspect, it need not occupy extra slot resources; on the other aspect, by way of reasonably setting the time condition for the stress test, the candidate users need not perform multi-slot processing and thereby the mobile stations of users are not required to support multi-slot processing. As can be seen, in the situation that the mobile stations of users are not required to support multi-slot processing and that no extra slot is required, the present invention can still implement the user pairing test, the system capacity is increased and the system call drop probability is reduced.

Figure 1 is a schematic diagram illustrating a frame structure of a conventional GSM system.

Figure 2 is a schematic diagram illustrating two users reusing a same time-frequency resource in a conventional GERAN/VAMOS system.

Figure 3 is a schematic diagram illustrating downlink modulation of users in a pair in the conventional GERAN/VAMOS system.

Figure 4 is a schematic diagram illustrating uplink modulation of users in a pair in the conventional GERAN/VAMOS system.

Figure 5 is a flowchart of a first preferred method for user pairing test according to the present invention.

Figure 6 is a flowchart of a second preferred method for user pairing test according to the present invention.

Figure 7 is a schematic diagram illustrating a method for user pairing test when a user is in a DTX state according to Embodiment 1 of the present invention.

Figure 8 is a schematic diagram illustrating a method for user pairing test when a user requests a TCH voice channel according to Embodiment 2 of the present invention.

Figure 9 is a schematic diagram illustrating a method for user pairing test when candidate users perform stress test on respective slots according to Embodiment 3 of the present invention.

To make the objective, technical scheme and merits of the present invention clearer, the present invention will be described hereinafter in detail with reference to accompanying drawings and embodiments.

According to an embodiment of the present invention, a time condition for stress test is preset; then, a base station notifies a candidate user to perform the stress test on a slot of the candidate user or a slot of another candidate user when the time condition for the stress test is satisfied, and to report a channel condition; finally, the base station adjusts transmission power of candidate users according to channel conditions of the candidate users, and when channel qualities of the candidate users meet channel quality requirements, multiplexes two candidate users onto a same time-frequency resource and releases redundant time-frequency resources. According to the method in this embodiment, on one aspect, it need not occupy extra slot resources; on the other aspect, by way of reasonably setting the time condition for the stress test, the candidate users need not perform multi-slot processing and thereby the mobile stations of users are not required to support multi-slot processing. As can be seen, in the situation that the mobile stations of users are not required to support multi-slot processing and that no extra slot is required, the present invention can still realize the user pairing test, the system capacity is increased and the system call drop probability is reduced.

According to an analysis of practical communication processes in the mobile communication system by inventors of the present invention, how to select the time condition for the stress test will be hereinafter described in detail.

Through research, during one communication process, a mobile user usually spends only 40% of time on talking while transmits no voice message in most time. Therefore, the GSM system introduces a Discontinuous Transmission (DTX) mechanism.

Functions of the DTX mechanism include:

1) Use of DTX can lower an interference level in the system and improve validity of the system;

2) Because a DTX transmitter is used, the total transmission time is reduced, and the life span of cells is increased while power consumption is reduced.

In order to realize the DTX, a Voice Activation Detection (VAD) technique should be used, and thus an indicator can be given immediately once talking pauses.

In a DTX state, a mobile station only transmits an inherent SACCH frame and a Silence Indicator (SID). The SID frame is used for generating “comfort noise”. The comfort noise is made manually and thus is generated regularly and periodically. When the comfort noise is decoded, a listener will not be sick of it. One main objective of using the comfort noise is that: when no voice need be transmitted, on one aspect, it is a must for system measurements; one the other aspect, it is generated on purpose so that the listener will not mistake a pause for connection interruption (i.e. call drop). The DTX transmission mode requires only a quite low speed, and only 260 bits of codes are transmitted every 480ms in this mode. Comparatively, in a normal communication state, a voice stream will generate 260 bits of codes every 20ms.

In the VOAMOS system, the DTX takes an important role in reducing interference between two users multiplexed onto a same time-frequency resource in a cell. On the downlink, when the TCH channel adopts the DTX technique, regarding one VAMOS pair, if the two users both need to transmit data, i.e. neither users are in the DTX state, the base station adopts the AQPSK modulation shown in Figure 3; if the TCH channel of one user is in the DTX state and the other user is not in the DTX state, the base station transmits a GMSK modulation signal to the user which is not in the DTX state; if TCH channels of the two users are both in the DTX state, the base station transmits only DTX information.

Therefore, the present invention proposes that: when a candidate user is in the DTX state and need not transmit the SID and SACCH, the candidate user can perform the stress test, i.e. “a candidate user is in the DTX state and need not transmit the SID and SACCH” may be taken as a time condition for stress test. Specifically, there may be two conditions: the candidate user can perform stress test on its occupied slot, or on a slot occupied by another user.

In addition, when a candidate user requests a TCH channel, the system has already completed authentication and encryption for the candidate user but hasn't allocated the time-frequency resource to the candidate user, the candidate user may adopt this interval to perform the stress test on a slot of another user, i.e. “a candidate user requests a TCH channel” may also be taken as a time condition for stress test.

Based on the above analysis, the present invention provides two kinds of methods for user pairing test, which will be described in detail hereinafter.

Figure 5 is a flowchart of a first preferred method for user pairing test according to the present invention. In the first preferred method, it is supposed that the candidate user performs stress test on a slot of another candidate user. As shown in Figure 5, the method is applicable to the GERAN/VAMOS system and includes the following:

Step 501: Preset a time condition for stress test.

According to the above analysis, the time condition preset for stress test in this step may be: “a candidate user is in the DTX state and need not transmit the SID and SACCH in a current frame” (called first time condition for short hereinafter), or “when a candidate user requests a TCH channel” (called second time condition for short hereinafter).

Step 502: The base station selects two users, a first user and a second user, as candidate users.

In this step, the base station may randomly select two users as the candidate users, or select two users having similar channel qualities as the candidate users according to channel qualities of users.

If the time condition preset for stress test is the second time condition, in this step, the base station must select one voice user and one user requesting a TCH channel as the candidate users for pairing test.

Step 503: The base station instructs the second user to perform stress test on a slot of the first user.

In this step, corresponding to the first time condition, the base station may determine whether mobile stations of the two selected users both support the VAMOS; if yes, the base station selects any of the two users as the second user; otherwise, the base station selects a user corresponding to a mobile station which does not support the VAMOS as the second user.

Corresponding to the second time condition, the voice user is selected as the first user and the user requesting a TCH channel is selected as the second user.

In this step, the base station may instruct the second user to perform the stress test through an Assignment Command, and transmits the slot of the first user and MAIO, or the slot of the first user and ARFCN which are contained in the Assignment Command to the second user. Herein, the slot on which the stress test is performed, i.e. the slot of the first user, must be transmitted to the second user, while just one of the MAIO and the ARFCN is transmitted. Whether to transmit the MAIO or the ARFCN is determined according to whether the system adopts a frequency hopping mode. When the system adopts the frequency hopping mode, the MAIO is transmitted; otherwise, the ARFCN is transmitted.

In the specific implementation, it is possible to take a spare bit or a spare bit combination in a channel type and TDMA offset field in a channel description message (Channel Description, Channel Description 2 or Channel Description 3) of the Assignment Command as an indicator for indicating the candidate user whether the stress test should be performed, and include the slot of the first user and MAIO or the slot of the first user and ARFCN into the Channel Description message of the Assignment Command to be transmitted to the second user.

Corresponding to the first time condition, the base station may include the Assignment Command into the FACCH channel and transmit it to the second user.

Corresponding to the second time condition, the base station may include the Assignment Command into the SDCCH channel and transmit it to the second user.

Step 504: When the time condition for stress test is satisfied, the second user performs the stress test on the slot of the first user and reports a channel condition to the base station.

In this step, the first user may not make any changes, and still transmit and receive data through sub-channel 1 on its slot according to its original training sequence. When the time condition for stress test is satisfied, the second user transmits the dummy data, or receives the dummy data, or transmits and receives the dummy data through sub-channel 2 on the slot of the first user by using a training sequence in a training sequence set different from a training sequence set which a training sequence used by the first user belongs to.

According to practical requirements, if only the uplink requires the stress test, the second user only transmits the dummy data through the sub-channel 2 on the slot of the first user; if only the downlink requires the stress test, the second user only receives the dummy data through the sub-channel 2 on the slot of the first user; if both the uplink and the downlink require the stress test, the second user receives and transmits the dummy data through the sub-channel 2 on the slot of the first user.

Step 505: According to channel conditions reported by the first user and the second user, the base station determines whether the channel qualities of the first user and the second user meet a preset channel quality requirement. If yes, proceed to Step 507; otherwise, proceed to Step 506.

Herein, channel quality requirements may be different for the uplink and the downlink according to practical application requirements, i.e. different channel quality requirements may be configured according to practical application requirements, so as to be adaptive to the practical application requirements more flexibly. For example, the channel quality requirements may be: channel conditions of uplinks and downlinks of two candidate users all reach a preset channel quality threshold, or channel conditions of downlinks of two candidate users reach a preset channel quality threshold, or channel conditions of uplinks of two candidate users reach a preset channel quality threshold.

Considering that the restriction of the user pairing in the practical system is centralized on the downlink, it is possible to configure a higher channel quality requirement for the downlink and a lower channel quality requirement for the uplink. Or, considering the complexity of the pairing test process, it is also possible to only consider the channel quality requirement of the downlink.

Step 506: The base station adjusts transmission power of the first user and the second user according to the channel conditions reported by the first user and the second user, and then Step 504 is performed again.

Through the determining in Step 505, when a current channel quality hasn’t reached the preset requirement, Step 506 is performed. Therefore, after adjusting the transmission power of the first user and the second user, the method returns to Step 506 to continue the stress test.

Step 507: The base station multiplexes the first user and the second user onto a same time-frequency resource, releases time-frequency resources occupied by the first user and the second user except for the multiplexed time-frequency resource.

Through the determining in Step 505, when a current channel quality reaches the preset requirement, it indicates that the pairing test succeeds. At this moment, the base station multiplexes the candidate users onto the same time-frequency resource and releases redundant time-frequency resources.

So far, the first preferred method for user pairing test is terminated.

Figure 6 is a flowchart of a second preferred method for user pairing test according to the present invention. In the second preferred method, it is supposed that a candidate user performs stress test on its own slot. As shown in Figure 6, the method is applicable to the GERAN/VAMOS system and includes the following steps:

Step 601: Preset a time condition for stress test.

In this step, the time condition preset for stress test may be: a candidate user is in the DTX state and need not transmit the SID and SACCH in a current frame.

Step 602: The base station selects candidate users.

In this step, the base station may randomly select the candidate users or select users having similar channel qualities as the candidate users according to channel qualities of the users.

The number of the selected candidate users may include the following two conditions:

First condition: two candidate users are selected. If only two candidate users are selected, it indicates that the two candidate users may be taken as objects of the pairing test. Then, transmission power of the two candidate users is adjusted according to channel conditions reported by the two candidate users. When the channel conditions meet the channel quality requirements, the two users are matched together.

Second condition: more than two candidate users are selected. If more than two candidate users are selected, it indicates that a pairing relation between the candidate users is relatively incompact. Transmission power of a candidate user may be adjusted according to a channel condition reported by the candidate user itself without reference to channel conditions of other candidate users. Then, every two of users having suitable channel conditions are selected according to channel conditions of the users.

Step 603: The base station instructs the candidate users to perform stress test on respective slots of the candidate users.

In this step, the base station may take an idle bit or an idle bit combination in a channel type and TDMA offset field in a channel description message (Channel Description, Channel Description 2 or Channel Description 3) of the Assignment Command as an indicator for indicating the candidate user whether stress test should be performed. The base station then adopts the indicator to instruct the candidate user to perform the stress test and report the channel condition, and transmits the Assignment Command carried in the FACCH to the candidate user.

Step 604: If the time condition for stress test is not satisfied, the base station transmits voice data of each candidate user through sub-channel 1 of each candidate user and transmits the dummy data through sub-channel 2. If the time condition for stress test is satisfied, the base station transmits the dummy data on both sub-channel 1 and sub-channel 2 of each candidate user. Each candidate user receives data through the sub-channel 1 on a slot of the candidate user, and reports a channel condition to the base station.

Step 605: The base station determines whether channel qualities of the candidate users meet preset channel quality requirements according to channel conditions reported by all the candidate users. If yes, proceed to Step 607; otherwise, proceed to Step 606.

If only two candidate users are selected in Step 602, referred to as a first user and a second user, the processing in Step 605 is that: according to the channel conditions reported by the first user and the second user, the base station determines whether the channel qualities of the first user and the second user meet the preset channel quality requirements; if yes, proceed to Step 607; otherwise, proceed to Step 606.

If more than two candidate users are selected in Step 602, the processing in Step 605 is that: according to a channel condition reported by each of the candidate users, the base station determines whether there is a candidate user meeting a preset channel quality requirement; if yes, proceed to Step 607; otherwise, proceed to Step 606 for candidate users which haven’t finished the stress test.

Step 606: According to a channel condition reported by each of the candidate users, the base station adjusts transmission power of sub-channel 1 and sub-channel 2 of each of the candidate users, and return to Step 604.

If only two candidate users are selected in Step 602, the processing in Step 606 is that: according to the channel conditions reported by the first user and the second user, the base station adjusts the transmission power of the sub-channel 1 and the sub-channel 2 of the first user and the second user, then returning to Step 604.

If more than two candidate users are selected in Step 602, the processing in Step 606 is that: according to a channel quality reported by each of the candidate users, the base station adjusts transmission power of sub-channel 1 and sub-channel 2 of each corresponding candidate user, then returning to Step 604.

Step 607: The base station multiplexes candidate users whose channel qualities meet the preset channel quality requirements onto a same time-frequency resource, and releases time-frequency resources occupied by the candidate users except the multiplexed time-frequency resource.

If only two candidate users are selected in Step 602, the processing in Step 607 is that: the base station multiplexes the first user and the second user onto the same time-frequency resource, and releases time-frequency resources occupied by the candidate users except the multiplexed time-frequency resource.

If more than two candidate users are selected in Step 602, the processing in Step 607 is that: determining whether candidate users for which the stress test is terminated but the user pairing is not completed include two candidate users with channel qualities meeting the preset channel quality requirements; if yes, multiplexing the two candidate users onto the same time-frequency resource, releasing the time-frequency resources occupied by the two candidate users except the multiplexed time-frequency resource, terminating the user pairing for the two candidate users, and then further determining whether there are candidate users with channel qualities meeting the preset channel quality requirements; and if there are candidate users with channel qualities meeting the preset channel quality requirements, performing Step 606 for the candidate users which haven’t finished the stress test.

So far, the second preferred method for user pairing test is terminated.

Hereinafter, the present invention will be described in detailed with reference to three embodiments.

Embodiment 1:

This embodiment provides a method for user pairing test when a user is in a DTX state. The method is applicable to the GERAN/VAMOS system.

Figure 7 is a schematic diagram illustrating a method for user pairing test when a user is in a DTX state according to Embodiment 1 of the present invention. As shown in Figure 7, it is supposed that MS1 and MS2 are voice users, respectively occupying time slots TS1 and TS5. Because the load of the system becomes heavier and heavier, the base station needs to assign some users having better channel conditions onto a same slot and a same frequency resource. In order to not affect channel conditions and communication qualities of users after the user pairing, it is necessary to perform pairing test before actual pairing and to adjust transmission power of two candidate users through the stress test method, so that the uplinks and downlinks of the two candidate users all have acceptable channel conditions.

In the practical system, not all mobile stations support the multi-slot processing capability. In order to expand the application scope of the method for user pairing test according to the present invention, this embodiment proposes: starting the user pairing test when a candidate user is in the DTX state and need not transmit the SID and SACCH in a current frame.

The base station takes the MS1 and the MS2 as two candidate users. If mobile stations of the two candidate users support the VAMOS, a slot of any of the two candidate users is selected as a slot used for the stress test. Otherwise, a slot of an earlier cell phone (i.e. legacy user) is selected as the slot used for the stress test. Hereinafter, it is supposed that the slot of the MS1 is selected as the slot used for the stress test. The base station transmits the Assignment Command to the MS2 through the FACCH, and takes an idle bit 7 in the channel type and TDMA offset field of the Channel Description message as an indicator for indicating whether to perform the stress test. For example, when bit 7 equals to 0, it indicates that the stress test is not performed; when bit 7 equals to 1, it indicates that the stress test starts. The slot number, and the MAIO or ARFCN value which are used during the stress test are included in the Channel Description message. When the MS2 is in the DTX state and need not transmit the SIN and SACCH in a current frame, the dummy data are transmitted or received on the TS1 of the MS1.

In the channel type and TDMA offset field, bit 6 is also an idle bit and may also be used as an indicator for indicating whether to perform the stress test. For example, when bit 6 equals to 0, it indicates that the stress test is not performed; when bit 6 equals to 1, it indicates that the stress test starts. Certainly, in the practical applications, bit 7 and bit 6 may be combined together as an indicator for indicating whether to perform the stress test. Besides, it is also possible to define many other methods for using an idle bit in the Channel Description message as an indicator for indicating whether to perform the stress test. However, for the sake of avoiding lengthiness of the present invention, the other methods will not be describe herein, but are still within the protection scope of the present invention.

On the downlink, the MS1 receives its own voice data on the TS1; meanwhile, when the MS2 is in the DTX state and need not transmit the SIN and SACCH in a current frame, the MS2 receives the dummy data transmitted by the base station on the TS1. In the VAMOS downlink modulation mode, the voice data transmitted to the MS1 and the dummy data transmitted to the MS2 are modulated by the AQPSK (or called AQM, the name has not been definitely determined yet); and the MS1 and the MS2 receive data through their respective sub-channels. Generally, in order to avoid extra signalling overhead, the MS1 may receive data through a legacy sub-channel without a change to the MS1, i.e. the MS1 uses the sub-channel 1. The MS2 receives the dummy data through the sub-channel 2, and therefore the MS2 must be a VAMOS cell phone. After receiving the dummy data, the MS2 checks the wireless channel quality and reports its measurement report of the dummy data on the TS1. The base station adjusts the transmission power of two sub-channels according to measurement reports of the two users, so that the two sub-channels both have acceptable channel conditions.

On the uplink, the MS1 transmits its voice data on the TS1; meanwhile, the MS2 transmits the dummy data modulated by the GMSK also on the TS1 in an idle frame. Generally, in order to avoid changing a transmission mode of the MS1, the training sequence of the MS1 is not changed and the MS2 transmits the dummy data by using a training sequence in a corresponding TSC Set 2. After receiving data transmitted by the two users on the TS1, the base station checks the wireless channel quality and adjusts the transmission power of the two users on the TS1 according to the wireless channel quality, so that the two users both have acceptable channel conditions on uplinks.

When uplinks and downlinks of the two candidate users all have acceptable channel conditions, the base station assigns the two users onto the TS1 and releases the slot resource occupied originally by the MS2, and then the pairing test process is completed. Certainly, the two users may also be assigned onto the slot of the MS2 or other slots, and then redundant resources are released.

During the pairing test process, the base station may transmit signalling to instruct the MS1 to transmit or receive the dummy data on the slot of the MS2 when the MS1 is in the DTX state and need not transmit the SID and SACCH in a current frame. In other words, any candidate user, as long as it is in the DTX state and need not transmit the SID and SACCH in its current frame, transmits or receives the dummy data on a slot of another user so as to increase the stress test efficiency.

During the pairing test process, considering the complexity, it is also possible that the stress test is performed only for the downlink or only for the uplink. When making a pairing test decision, it is also possible that only the channel quality requirement of the downlink is satisfied, or only the channel quality requirement of the uplink is satisfied, or both channel quality requirements of the uplink and the downlink are satisfied.

In the method for user pairing test according to this embodiment, because the mobile stations of the users need to process data on only one slot, the mobile stations are not required to support the multi-slot transmission capability, and the application scope of the method of this embodiment is expanded.

The basic idea of this embodiment includes: when the user is in the DTX state and need not transmit the SID and SACCH in a current frame, performing the pairing test on the slot for the stress test, transmitting or receiving the data on the slot for the stress test, and reporting a measurement report; adjusting the transmission power of each sub-channel by the base station according to the measurement report so that the transmission power maintains in an acceptable level; and terminating the pairing test and releasing the redundant resources when both the uplink and the downlink have acceptable channel conditions. Thereby, in the situation that the mobile stations of the users are not required to support the multi-slot processing and no extra slot is required, the user pairing test is realized, the system capacity is increased and the system call drop probability is reduced.

Besides the implementation manner in Embodiment 1 of the present invention, according to the main idea of this embodiment, many other methods may be defined to perform the stress test when the user is in the DTX state and to provide an indicator in the Channel Description message to indicate whether to perform the stress test. However, for the sake of avoiding lengthiness of the present invention, the other methods will not be described herein but are still within the protection scope of the present invention.

Embodiment 2:

This embodiment provides a method for user pairing test when a user requests a TCH voice channel, which is applicable to the GERAN/VAMOS system.

Figure 8 is a schematic diagram illustrating a method for user pairing test when a user request a TCH voice channel according to Embodiment 2 of the present invention. As shown in Figure 8, it is supposed that MS1 is a voice user and occupies time slot TS1. Because the load of the system becomes heavier and heavier, the base station needs to assign some users having better channel conditions onto a same slot and a same frequency resource. In order to not affect channel conditions and communication qualities of users after the user pairing, it is necessary to perform pairing test before actual pairing and to adjust transmission power of two candidate users through the stress test method, so that the uplinks and downlinks of the two candidate users all have acceptable channel conditions.

In the practical system, not all mobile stations support the multi-slot processing capability. In order to expand the application scope of the method for user pairing test according to the present invention, this embodiment proposes that the base station starts the user pairing test when a user starts requesting a TCH channel. Suppose that the MS2 is requesting the TCH channel and has finished authentication and encryption, the base station transmits Assignment Command signalling to the MS2 through the SDCCH, and includes the slot number and the MAIO value, or the slot number and the ARFCN which are available to the MS2 into the Channel Description message. It is supposed that the MS1 and the MS2 are two candidate users and that the MS2 transmits or receives the dummy data on the TS1 occupied by the MS1.

On the downlink, the MS1 receives its own voice data on the TS1, and meanwhile, the MS2 receives the dummy data transmitted by the base station also on the TS1. In the VAMOS downlink modulation mode, the voice data transmitted to the MS1 and the dummy data transmitted to the MS2 are modulated by the AQPSK (or called AQM, the name has not been definitely determined yet); and the MS1 and the MS2 receive data through their respective sub-channels. Generally, in order to avoid extra signalling overhead, the MS1 may receive data through a legacy sub-channel without a change to the MS1, i.e. the MS1 uses the sub-channel 1. The MS2 receives the dummy data through the sub-channel 2, and therefore the MS2 must be a VAMOS cell phone. After receiving the dummy data, the MS2 checks the wireless channel quality and reports its measurement report of the dummy data on the TS1. The base station adjusts the transmission power of two sub-channels according to measurement reports of the two users, so that the two sub-channels both have acceptable channel conditions.

On the uplink, the MS1 transmits its voice data on the TS1; meanwhile, the MS2 transmits the dummy data modulated by the GMSK also on the TS1. Generally, in order to avoid changing a transmission mode of the MS1, the training sequence of the MS1 is not changed and the MS2 transmits the dummy data by using a training sequence in a corresponding TSC Set 2. After receiving data transmitted by the two users on the TS1, the base station checks the wireless channel quality and adjusts the transmission power of the two users on the TS1 according to the wireless channel quality, so that the two users both have acceptable channel conditions on uplinks.

When uplinks and downlinks of the two candidate users all have acceptable channel conditions, the base station assigns the two users onto the TS1 and the user pairing test process is completed. Certainly, the two users may also be assigned onto other slots, and then redundant resources are released.

During the pairing test process, the base station may transmit the Assignment Command signalling through the SDCCH, and takes an idle bit 7 in the channel type and TDMA offset field of the Channel Description message as an indicator for indicating whether to perform the stress test. For example, when bit 7 equals to 0, it indicates that the stress test is not performed; when bit 7 equals to 1, it indicates that the stress test starts. Specifically, the slot number, and the MAIO value or ARFCN value which are used during the stress test are included in the Channel Description message.

The basic idea of this embodiment includes: performing pairing test for one voice user and one user which is requesting the TCH channel, transmitting or receiving data on the slot occupied by the voice user, and reporting a measurement report; adjusting the transmission power of each sub-channel by the base station so that the transmission power maintains in an acceptable level; terminating the pairing test and releasing the redundant resources when both the uplink and the downlink have acceptable channel conditions. Thereby, in the situation that the mobile stations of the users are not required to support the multi-slot processing and no extra slot is required, the user pairing test is realized, the system capacity is increased and the system call drop probability is reduced.

Besides the implementation manner in Embodiment 2 of the present invention, according to the main idea of this embodiment, many other methods may be defined to perform the stress test when the user requests the TCH channel and to provide an indicator in the Channel Description message to indicate whether to perform the stress test. However, for the sake of avoiding lengthiness of the present invention, the other methods will not be described herein but are still within the protection scope of the present invention.

Embodiment 3:

This embodiment provides a method for user pairing test when candidate users perform stress test on their respective slots, which is applicable to the GERAN/VAMOS system.

Figure 9 is a schematic diagram illustrating a method for user pairing test when candidate users perform stress test on respective slots according to Embodiment 3 of the present invention. As shown in Figure 9, it is supposed that the MS1 and the MS2 are voice users, occupying time slots TS1 and TS5 respectively.

The base station selects the MS1 and the MS2 as two candidate users. The base station transmits signalling to the MS1 and the MS2 through the FACCH, and takes an idle bit 7 in the channel type and TDMA offset field of the Channel Description message as an indicator for indicating whether to perform the stress test. For example, when bit 7 equals to 0, it indicates that the stress test is not performed; when bit 7 equals to 1, it indicates that the stress test starts.

Adopting the AQPSK modulation mode, the base station transmits the voice data through the sub-channel 1 and transmits the dummy data through the sub-channel 2. When a user is in the DTX state and need not transmit the SID and SACCH in a current frame, the base station still adopts the AQPSK modulation mode to transmit the dummy data through the sub-channel 1 and the sub-channel 2 simultaneously. In other words, transmission of the dummy data continues in idle frames of users and thus the downlink need not change over to the GMSK modulation mode to transmit the dummy data; further, the users may also receive the stress test in the idle frames and it is beneficial to obtaining a more accurate pairing test result.

A user 1 and a user 2 respectively receive data only through the sub-channel 1 on the TS1 and the TS5, while do not process the dummy data transmitted through the sub-channel 2. Through the sub-channel 1, what is transmitted in the non-DTX state is the voice data, and what is transmitted in the DTX state is the dummy data. The user 1 and the user 2 report channel conditions to the base station according to the received data. The base station adjusts the transmission power of the sub-channel 1 and the sub-channel 2 according to the channel conditions of the user 1 and the user 2.

If the channel conditions of the user 1 and the user 2 both meet specific channel quality requirements (set by the system), the user 1 and the user 2 are multiplexed onto a same time-frequency resource, and the redundant resources are released.

During the pairing test process, considering the complexity, it is possible to perform the stress test only on the downlink.

The basic idea of this embodiment includes: during the pairing test, when the user is in the DTX state and need not transmit the SID and SACCH in a current frame, continuing the stress test on the slot occupied by the user, receiving by the user the dummy data transmitted by the base station through the sub-channel 1, and reporting a measurement report; adjusting the transmission power of the sub-channel 1 and the sub-channel 2 by the base station according to measurement reports so that the transmission power meets specific channel quality requirements; when both channel conditions of the user 1 and the user 2 meet specific channel quality requirements, multiplexing the user 1 and the user 2 onto a same time-frequency resource, and terminating the pairing test. Thereby, in the situation that the mobile stations of the users are not required to support the multi-slot processing and no extra slot is required, the user pairing test is realized, the system capacity is increased and the system call drop probability is reduced.

Besides the implementation manner in Embodiment 3 of the present invention, according to the main idea of this embodiment, many other methods may be defined to continue the stress test on the slot occupied by a user when the user is in the DTX state and to provide an indicator in the Channel Description message to indicate whether to perform the stress test. However, for the sake of avoiding lengthiness of the present invention, the other methods will not be described herein but are still within the protection scope of the present invention.

The foregoing is only embodiments of the present invention. The protection scope of the present invention, however, is not limited to the above description. Any change or substitution, easily occurring to those skilled in the art, should be covered by the protection scope of the present invention.

Claims

A method for user pairing test, applicable to a Voice services over Adaptive Multi-user channels on One Slot (VAMOS) system in which multiple users are multiplexed onto a same slot, characterized by comprising presetting a time condition for stress test, and further comprising steps of:

A, selecting, by a base station, two users including a first user and a second user as candidate users;

B, instructing, by the base station, the second user to perform the stress test on a slot of the first user;

C, when the time condition for the stress test is satisfied, performing, by the second user, the stress test on the slot of the first user, and reporting a channel condition to the base station;

D, determining, by the base station according to channel conditions reported by the first user and the second user, whether channel qualities of the first user and the second user meet preset channel quality requirements; if the channel qualities of the first user and the second user meet the preset channel quality requirements, proceeding to step F; otherwise, proceeding to step E;

E, adjusting, by the base station according to the channel conditions reported by the first user and the second user, transmission power of the first user and the second user; and returning to the step C; and

F, multiplexing, by the base station, the first user and the second user onto a same time-frequency resource, and releasing time-frequency resources occupied by the first user and the second user except the time-frequency resource multiplexed.
The method of claim 1, wherein

the time condition for the stress test is that the second user is in a Discontinuous Transmission (DTX) state and that the second user need not transmit a Silence Indicator and a Slow Associated Control Channel (SACCH) in a current frame.
The method of claim 1, wherein

the time condition for the stress test is that the second user requests a voice Traffic Channel (TCH).
The method of any of claims 1-3, wherein the step A comprises:

selecting, by the base station, two users as the candidate users randomly; or selecting, by the base station according to channel qualities of users, two users with similar channel qualities as the candidate users.
The method of claim 2, wherein the step B comprises:

determining, by the base station, whether mobile stations of the two users both support VAMOS;

if the mobile stations of the two users both support the VAMOS, selecting any of the two users as the second user;

otherwise, selecting a user corresponding to a mobile station which does not support the VAMOS as the second user.
The method of claim 3, wherein a mobile station of the second user support VAMOS.
The method of any of claims 1-3, wherein instructing by the base station the second user to perform the stress test on the slot of the first user in the step B comprises:

instructing, by the base station, a candidate user to perform the stress test through an assignment command;

including the slot of the first user and a Mobile Allocation Index Offset (MAIO), or the slot of the first user and an Absolute Radio Frequency Channel Number (ARFCN) into the assignment command; and

notifying the second user to report the channel condition.
The method of claim 7, wherein

a spare bit or a spare bit combination in a channel type and Time Division Multiple Access (TDMA) offset field in a channel description message of the assignment command is taken as an indicator for indicating the candidate user whether the stress test should be performed; and

the slot of the first user and the MAIO, or the slot of the first user and the ARFCN are included into the channel description message of the assignment command.
The method of claim 7, wherein

when the time condition for the stress test is that the second user is in the DTX state and the second user need not transmit the SID and the SACCH in the current TDMA frame, the assignment command is transmitted to the second user through a Fast Associated Control Channel (FACCH);

when the time condition for the stress test is that the second user requests the TCH, the assignment command is transmitted to the second user through a Stand-Alone Dedicated Control Channel (SDCCH).
The method of any of claims 1-3, wherein performing the stress test on the slot of the first user by the second user in the step C comprises:

through a sub-channel 2 of the first user, transmitting dummy data, or receiving the dummy data, or receiving and transmitting the dummy data by the second user by using a training sequence in a training sequence set different from a training sequence set which a training sequence used by the first user belongs to.
The method of any of claims 1-3, wherein

the preset channel quality requirements are that channel conditions of uplinks and downlinks of the two candidate users all reach a preset channel quality threshold, or that channel conditions of the downlinks of the two candidate users reach the preset channel quality threshold, or that channel conditions of the uplinks of the two candidate users reach the preset channel quality threshold.
A method for user pairing test, applicable to a Voice services over Adaptive Multi-user channels on One Slot (VAMOS) system in which multiple users are multiplexed onto a same slot, characterized by comprising presetting a time condition for stress test, and further comprising steps of:

a, selecting, by a base station, candidate users;

b, instructing, by the base station, the candidate users to perform the stress test on respective slots of the candidate users;

c, when the time condition for the stress test is not satisfied, transmitting, by the base station, voice data of each candidate user through a sub-channel 1 of the candidate user, and transmitting dummy data through a sub-channel 2; when the time condition for the stress test is satisfied, transmitting, by the base station, the dummy data through both the sub-channel 1 and the sub-channel 2 of each candidate user; receiving, by each candidate user, data through the sub-channel 1 of a slot of the candidate user, and reporting a channel condition to the base station;

d, determining, by the base station according to the channel condition reported by each candidate user, whether a channel quality of the candidate user meet a preset channel quality requirement; if the channel quality of each candidate user meet the preset channel quality requirement, proceeding to step f; otherwise, proceeding to step e;

e, adjusting, by the base station according to the channel condition reported by each candidate user, transmission power of the sub-channel 1 and the sub-channel 2 of each candidate user; and returning to the step c;

f, multiplexing, by the base station, candidate users whose channel qualities meeting the preset channel quality requirement onto a same time-frequency resource, and releasing time-frequency resources occupied by the candidate users except the time-frequency resource multiplexed.
The method of claim 12, wherein

the time condition for the stress test is that the candidate users are in a Discontinuous Transmission (DTX) state and that the candidate users need not transmit a Silence Indicator and a Slow Associated Control Channel (SACCH) in a current frame.
The method of claim 13, wherein the candidate users selected in the step a are two, a first user and a second user;

the step d comprises: determining, by the base station according to channel conditions reported by the first user and the second user, whether channel qualities of the first user and the second user meet preset channel quality requirements; if the channel qualities of the first user and the second user meet the preset channel quality requirements, proceeding to the step f; otherwise, proceeding to the step e;

the step e comprises: adjusting, by the base station according to the channel conditions reported by the first user and the second user, the transmission power of the sub-channel 1 and the sub-channel 2 of the first user and the second user; and returning to the step c; and

the step f comprises: multiplexing, by the base station, the first user and the second user onto the same time-frequency resource, and releasing time-frequency resources occupied by the first user and the second user except the time-frequency resource multiplexed.
The method of claim 13, wherein the candidate users selected in the step a are more than two;

the step d comprises: determining, by the base station according to channel conditions reported by the candidate users, whether there is a candidate user whose channel quality meets the preset channel quality requirement; if there is the candidate user whose channel quality meets the preset channel quality requirement, terminating the stress test for the candidate user and proceeding to the step f; otherwise, proceeding to the step e for a candidate user for which the stress test is not terminated;

the step e comprises: adjusting, by the base station according to the channel conditions reported by the candidate users, the transmission power of the sub-channel 1 and the sub-channel 2 of each corresponding candidate user; and returning to the step c;

the step f comprises: determining whether candidate users for which the stress test is terminated but user pairing is not completed include two candidate users whose channel qualities meet preset channel quality requirements; if including the two candidate users, multiplexing the two candidate users onto the same time-frequency resource, releasing time-frequency resources occupied by the two candidate users except the time-frequency resource multiplexed, terminating the user pairing for the two candidate users, and determining whether there is a candidate user whose channel quality does not meet the preset channel quality requirement; if there is a candidate user whose channel quality does not meet the preset channel quality requirement, performing the step e for a candidate user for which the stress test is not terminated.
The method of any of claims 12-15, wherein the step a comprises:

selecting, by the base station, users as the candidate users randomly; or selecting, by the base station according to channel qualities of users, users with similar channel qualities as the candidate users.
The method of any of claims 12-15, wherein instructing by the base station the candidate users to perform the stress test on the respective slots of the candidate users in the step b comprises:

taking a spare bit or a spare bit combination in a channel type and Time Division Multiple Access (TDMA) offset field in a channel description message of an assignment command as an indicator for indicating the candidate users whether the stress test should be performed;

instructing the candidate users to perform the stress test through the assignment command, and to report the channel conditions; and

transmitting the assignment command through a Fast Associated Control Channel (FACCH).