WO2009038523A1

WO2009038523A1 - Improved uplink access in a wireless communications tdd system

Info

Publication number: WO2009038523A1
Application number: PCT/SE2008/050866
Authority: WO
Inventors: Jie Mao; Huaisong Zhu; Jingyue Nie
Original assignee: Telefonaktiebolaget L M Ericsson (Publ)
Priority date: 2007-09-17
Filing date: 2008-07-11
Publication date: 2009-03-26
Also published as: CN101803445A; TW200917704A

Abstract

A method for use in a cellular communications TDD system, the system comprising at least a first controlling transceiver and a number of user terminals within a geographical area in the system. The controlling receiver controls the traffic to ( down link ) and from ( uplink ) said user terminals. The uplink traffic can comprise both scheduled and non- scheduled traffic, and the scheduled uplink traffic is preceded by uplink scheduling information. A number of user terminals in the system transmit continuously in a non- scheduled uplink channel of the system, said transmissions involving at least one of the following: some of said scheduling information, data traffic, a bit stream according to a pre-defined format.

Description

IMPROVED UPLINK ACCESS IN A WIRELESS COMMUNICATIONS

TDD SYSTEM

TECHNICAL FIELD

The present invention relates to a method and arrangement in a user equipment and to a method and arrangement in a base station. More particularly the present invention relates to an improved mechanism for uplink access in a wireless communication system.

BACKGROUND

Currently, standardized and commercially deployed radio access technologies are proliferated, for use in wireless communication systems. Such radio access technologies include cellular communication systems which operate on the Time Division Duplex (TDD) principle. An example of a cellular wireless communication system operating on TDD is Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems.

In a TD-SCDMA system, as well as in other cellular wireless communication systems, there will be a first transceiver, a so called base station, or in this instance a Node B, which serves to control the traffic to and from user terminals within a geographical area, a cell, of the wireless communication system.

The traffic for the user terminals to the Node B is referred to as uplink traffic, and traffic from the Node B to the user terminals is referred to as downlink traffic.

TD-SCDMA EUL is a development of the TD-SCDMA system, with EUL standing for Enhanced Uplink.

In the TD-SCDMA EUL, system, there are two kinds of resource in uplink: scheduled and non-scheduled resources. Services with high Quality of Service (QoS) requirements, such as Guaranteed Bit Rate (GBR) and Signalling Radio Bearer (SRB) traffic are transmitted on non-scheduled resources, and services with low QoS requirements are transmitted on scheduled resources.

The uplink transmission on scheduled resources is preceded by the transmission of so called scheduling information from the user terminal to the Node B. In some situations, the user terminals transmit the scheduling information to the Node B using one of a number of signatures which are available in that particular cell. The signatures are chosen randomly by the user terminals, which means that collisions may occur, thus stopping some user terminals from accessing the uplink, and causing delays in the transfer of uplink information.

In TD-SCDMA Enhanced UpLink (EUL) systems, there are two kinds of resources in uplink: scheduled and non-scheduled resources. As mentioned previously, services with high QoS requirement, such as GBR and SRB traffic, are transmitted on non-scheduled resources, as configured by the Radio Network Controller (RNC), and services with low QoS requirement are transmitted on scheduled resources.

In a situation where a user equipment has no grant from the Node B, or from the RNC, to transmit, and the Total E-DCH Buffer Status (TEBS) becomes larger than zero, the transmission of so called Scheduling Information is triggered via the E-DCH Random Access Uplink Control Channel, (E-RUCCH).

The procedure for transmitting traffic from the Node B may be described as follows:

Firstly, when a user equipment needs to transfer scheduling information in the E-RUCCH, the user equipment selects an uplink synchronization code (SYNC_UL) signature randomly from an available signature sub-set, and sends the signature to the Node B. The

Node B receives the signature from the user equipment. Then, the Node B informs the user equipment regarding the power setting and timing adjustment information via the

Fast Physical Access Channel (FPACH). The user equipment will send its scheduling information to the Node B in the E-DCH Random Access Uplink Control Channel, the E-

RUCCH, with adjusted initial power and timing advance to the Node B. The Node B receives the user equipment's scheduling information, and allocates a transmission grant to the user equipment via the E-DCH Absolute Grant Channel, the E-AGCH according to the scheduling algorithm used by the Node B. Finally, the user equipment accepts the grant, and transfers its data to the Node B on the Enhanced Uplink Physical Channel, the

E-PUCH.

However, the process of obtaining a scheduling grant from the Node B for a user equipment may be unsuccessful. A problem associated with the described procedure will now be presented. In a TD-SCDMA system, there are eight SYNC_UL signatures available in a cell, those signatures being divided into two subsets, one subset for the access of Random Access Channel, RACH, information and the other subset for the access of the E-DCH Random Access Uplink Control Channel, E-RUCCH, information.

However, if the user equipment has no grant and needs to transfer data to the Node B, the user equipment will share the E-RUCCH resource with other user equipments which are in the same situation.

A user equipment which transfers scheduling information in the E-RUCCH will select an available SYNC_UL signature randomly and transmit to the Node B. If more than one user equipment is in the same situation, there is a risk of collision in the uplink access, and of course, if there is larger number of user equipments involved, the risk of collision probability will grow.

Consequently, there may be some user equipments which cannot access the uplink on their first attempt, and after delaying for a period, the user equipment will send its SYNC_UL again. Then, when the user equipment gets an indication from the Node B to transfer, the user equipment will send scheduling information by E-RUCCH, in the manner previously described.

As will be realized, due to the collision described above, it may take quite a long time for some of the user equipments in the system before their scheduling information will arrive at the Node B. This will decrease the SYNC_UL signature access successful rate, and cause a degrading of the system performance.

SUMMARY

It is therefore an object of the present invention to obviate at least some of the above disadvantages and provide an improved mechanism for uplink access in a wireless communication system.

According to a first aspect, the object is achieved by a method in a base station for receiving information from a user equipment. The base station and the user equipment are comprised within a wireless communication system. The base station and the user equipment are further adapted to exchange wireless signals. The wireless communication system is adapted to operate according to the TDD principle. The method comprises receiving scheduling information from the user equipment. The scheduling information is received in a non-scheduled uplink channel of the wireless communication system.

According to a second aspect, the object is also achieved by an arrangement in a base station. The arrangement is adapted to receive information from a user equipment. The base station and the user equipment are comprised within a wireless communication system. The base station and the user equipment are adapted to exchange wireless signals with each other. The wireless communication system is adapted to operate according to the TDD principle. The arrangement comprises a receiving unit. The receiving unit is adapted to receive scheduling information from the user equipment in a non-scheduled uplink channel of the wireless communication system.

According to a third aspect, the object is achieved by a method in a user equipment for sending information to a base station. The user equipment and the base station are comprised within a wireless communication system. The user equipment and the base station are also adapted to exchange wireless signals. The wireless communication system is adapted to operate according to the TDD principle. The method comprises sending scheduling information to the base station in a non-scheduled uplink channel of the wireless communication system.

According to a fourth aspect, the object is also achieved by an arrangement in a user equipment. The arrangement is adapted to send information to a base station. The user equipment and the base station are comprised within a wireless communication system. Also, the user equipment and the base station are adapted to exchange wireless signals. The wireless communication system is adapted to operate according to the TDD principle. The arrangement comprises a sending unit. The sending unit is adapted to send scheduling information to the base station in a non-scheduled uplink channel of the wireless communication system.

Since user terminals according to the invention may access a non-scheduled uplink channel continuously, they may transmit scheduling information without the conflicts caused by the signature choice according to the prior art. Thus an improved mechanism for uplink access in a wireless communication system is provided If there is no other data sent in uplink, uplink synchronization and beam forming can be made based on the scheduling information sent to the base station continuously per every Time Transmission Interval (TTI) or per every several TTI.

Thereby the user equipment's waiting time in uplink access is reduced, without adding extra signalling or parameters. Uplink synchronization and beam forming could be made even when there is no other data sent in uplink, which improves the general system performance.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described more in detail in relation to the enclosed drawings, in which:

Figure 1 is a schematic block diagram illustrating a wireless communication system according to some embodiments.

Figure 2 is a schematic block diagram illustrating exemplary components of a base station according to some embodiments.

Figure 3A is a schematic block diagram illustrating exemplary components of a user equipment according to some embodiments.

Figure 3B is a schematic block diagram illustrating a user equipment according to some embodiments where the user equipment is embodied as a cellular telephone.

Figure 4 is a combined block- and signalling diagram depicting at least parts of the signalling between the user equipment and the base station according to an embodiment.

Figure 5 is a schematic flow chart illustrating an embodiment of the present method in a base station. Figure 6 is a schematic block diagram illustrating an arrangement in a base station according to some embodiments.

Figure 7 is a schematic flow chart illustrating an embodiment of the present method in a user equipment.

Figure 8 is a schematic block diagram illustrating an arrangement in a user equipment according to some embodiments.

Figure 9 is a schematic flow chart illustrating an embodiment of the present method in a user equipment.

Figure 10 is a schematic block diagram illustrating an arrangement in a user equipment according to some embodiments.

DETAILED DESCRIPTION

The invention is defined as a method and an arrangement in a base station and a method and an arrangement in a user equipment, which may be put into practice in the embodiments described below. This invention may, however, be embodied in many different forms and should not be considered as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It should be understood that there is no intent to limit the present method and arrangement in a base station and method and arrangement in a user equipment, to any of the particular forms disclosed, but on the contrary, the present methods and arrangements are to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the claims.

Still other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.

Figure 1 is a schematic block diagram illustrating an exemplary wireless communication system 100, according to some embodiments. The wireless communication system 100 comprises a base station 1 10 defining a cell 120, a user equipment 130 and a control node 140.

The wireless communication system 100 may sometimes be referred to as a wireless cellular communications system.

The base station 1 10 may also be referred to as e.g. an access point, a Node B, a controlling transceiver, a first transceiver, an evolved Node B (eNode B) and/or a base transceiver station, Access Point Base Station, base station router, etc depending e.g. of the radio access technology and terminology used. In the rest of the description, the term "base station" will be used for denoting the base station 1 10, in order to facilitate the comprehension of the present methods and arrangements.

The base station 1 10 serves to control the traffic to and from user equipment 130, within a certain geographic area such as the cell 120 in the wireless communication system 100.

The user equipment 130 may be represented by e.g. a wireless communication terminal, a mobile cellular telephone, a user terminal, a Personal Communications Systems terminal, a Personal Digital Assistant (PDA), a laptop, a computer or any other kind of device capable of managing radio resources may communicate wirelessly with the base station 1 10 within the wireless communication system 100. A Personal Communication System terminal may combine a cellular radiotelephone with data processing, facsimile and data communications capabilities. A PDA may comprise a radiotelephone, a pager, an Internet/intranet access device, a web browser, an organizer, calendars and/or a global positioning system (GPS) receiver. The user equipment 130 may be referred to as a "pervasive computing" device. However, in the rest of the description, the term "user equipment" will consistently be used for denoting the user equipment 130 in order to facilitate the comprehension of the present methods and arrangements. The wireless communication system 100 also comprises a control node 140. The control node 140 may be e.g. a Radio Network Controller (RNC). The Radio Network Controller 140 is a governing element in the wireless communication system 100, responsible for control of base stations e.g. the base station 1 10, which are connected to the Radio Network Controller 140. The Radio Network Controller 140 may carry out radio resource management; some of the mobility management functions and may be the point where encryption may be done before user data is sent to and from the at least one user equipment 130.

The user equipment 130 may communicate with other user equipments, or devices not shown, via the base station 110 comprised within the wireless communication system 100.

The traffic from the user equipment 130 to the base station 110 is referred to as uplink traffic (UL), and traffic from the base station 110 to the user equipment 130 is referred to as downlink traffic (DL), as illustrated in Figure 1.

The wireless communication system 100 may comprise one or more networks of any type, including a Local Area Network (LAN); a Wide Area Network (WAN); a Metropolitan Area Network (MAN); a telephone network, such as a Public Switched Telephone Network (PSTN) or a Public Land Mobile Network (PLMN); a satellite network; an intranet, the Internet; or a combination of these or other networks. The PLMN may further comprise a packet-switched sub-network, such as, for example, General Packet Radio Service (GPRS), Cellular Digital Packet Data (CDPD), or Mobile Internet Protocol (IP) Network.

The wireless communication system 100 may be based on technologies such as e.g. Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Wideband Code Division Multiple Access (WCDMA), CDMA 2000, High Speed Packet Access (HSPA), including Enhanced UpLink (EUL) and High Speed Downlink Packet Data Access (HSDPA), EVDO version of CDMA 2000 etc, just to mention some examples.

However, the present solution may be used with particular advantage in wireless communication systems 100 which operate on the Time Division Duplex (TDD) principle. The invention may be applied to a wide range of TDD systems, but will in the following be explained with reference to a so called TD-SCDMA system, Time Division Synchronous Code Division Multiple Access.

TD-SCDMA, is a 3G mobile telecommunications standard, being pursued in the People's Republic of China by the Chinese Academy of Telecommunications Technology (CATT).

TD-SCDMA uses TDD, in contrast to the Frequency Division Duplex (FDD) scheme used by e.g. W-CDMA. By dynamically adjusting the number of timeslots used for downlink and uplink, the system 100 may more easily accommodate asymmetric traffic with different data rate requirements on downlink and uplink than FDD schemes. Since it does not require paired spectrum for downlink and uplink, spectrum allocation flexibility is also increased. Also, using the same carrier frequency for uplink and downlink means that the channel condition is the same on both directions, and the base station 130 may deduce the downlink channel information from uplink channel estimates, which is helpful to the application of beam forming techniques.

TD-SCDMA also uses TDMA in addition to the CDMA used in WCDMA. This may reduce the number of users in each timeslot, which reduces the implementation complexity of multi-user detection and beam forming schemes.

Further, in TD-SCDMA, uplink signals may be synchronized at the base station 130, achieved by continuous timing adjustments. This may reduce the interference between user equipments 130 of the same timeslot using different codes by improving the orthogonality between the codes, therefore increasing system capacity.

It will be appreciated that the number of components illustrated in Figure 1 is purely exemplary. Other configurations with less, more, or a different arrangement of components may be implemented. Moreover, in some embodiments, one or more components in Figure 1 may perform one or more of the tasks described as being performed by one or more other components in Figure 1. To just mention one example, the functionality of the Radio Network Controller 140 may be distributed to the base station 110 in some embodiments. Figure 2 illustrates one exemplary implementation of the base station 110. The base station 1 10 may comprise e.g. a transceiver 205, a processing unit 210, a memory 215, an interface 220, a bus 225 and an antenna 230. The control node 140 may also be similarly configured; however, the control node 140 may not comprise the transceiver 205, according to some embodiments.

The transceiver 205 may comprise transceiver circuitry for transmitting and/or receiving symbol sequences using radio frequency signals via one or more antennas 230. The one or more antennas 230 may comprise a single antenna 230 or an antenna array and may comprise directional and/or omni-directional antennas 230.

The processing unit 210 may comprise a processor, microprocessor, or processing logic that may interpret and execute instructions. Further, the processing unit 210 may perform all data processing functions for the base station 1 10. The memory 215 may provide permanent, semi-permanent, or temporary working storage of data and instructions for use by the processing unit 210 in performing device processing functions. Also, the memory 215 may comprise a primary storage memory unit such as a processor register, a cache memory, a Random Access Memory (RAM) or similar. The memory unit 215 may however in some embodiments comprise a secondary memory unit such as a Read Only Memory (ROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), programmable read-only memory (PROM) or erasable programmable read-only memory (EPROM) or a hard disk drive. The memory unit 215 may however in some embodiments comprise an off-line storage memory unit, a flash memory, a USB memory or a memory card. The memory unit 215 may further in some embodiments comprise a Network- attached storage (NAS) or in fact any other appropriate medium such as and/or optical recording medium and its corresponding drive, or any other disk, tape or media that can hold machine readable data.

The interface 220 may comprise circuitry for interfacing with a link that connects e.g. to the base station 110. The bus 225 may interconnect the various components 205, 210, 215, 220, 230 of the base station 1 10 to permit the components to communicate with one another. The configuration of components of the base station 1 10 illustrated in Figure 2 is for illustrative purposes only. Other configurations with less, more, or a different arrangement of components may be implemented.

Figure 3A illustrates the user equipment 130 consistent with an exemplary embodiment. The user equipment 130 may comprise a transceiver 305, a processing unit 310, a memory 315, an input device 320, an output device 325, and a bus 330.

The transceiver 305 may comprise transceiver circuitry for transmitting and/or receiving symbol sequences using radio frequency signals via one or more antennas.

The processing unit 310 may comprise a Central Processing Unit (CPU), processor, microprocessor, or processing logic that may interpret and execute instructions. The processing unit 310 may perform all data processing functions for inputting, outputting, and processing of data, comprising data buffering and device control functions, such as call processing control, user interface control, or the like.

The memory 315 may provide permanent, semi-permanent, or temporary working storage of data and instructions for use by the processing unit 310 in performing device processing functions. The memory 315 may comprise ROM, RAM, large-capacity storage devices, such as a magnetic and/or optical recording medium and its corresponding drive, and/or other types of memory units. The input device 320 may comprise mechanisms for entry of data into the user equipment 130. The key pad may permit manual user entry of data into the user equipment 130. The microphone may comprise mechanisms for converting auditory input into electrical signals. The display unit may comprise a screen display that may provide a user interface, e.g., a graphical user interface that can be used by a user for selecting device functions. The screen display of the display unit may comprise any type of visual display, such as, for example, a Liquid Crystal Display (LCD), a plasma screen display, a Light-Emitting Diode (LED) display, a Cathode Ray Tube (CRT) display, an Organic Light-Emitting Diode (OLED) display, etc.

The output device 325 may comprise mechanisms for outputting data in audio, video and/or hard copy format. For example, the output device 325 may comprise a speaker

(not shown) that includes mechanisms for converting electrical signals into auditory output. The output device 325 may further comprise a display unit that displays output data to the user. For example, the display unit may provide a graphical user interface that displays output data to the user. The bus 330 may interconnect the various components of the user equipment 130 to permit the components to communicate with one another.

The configuration of components of the user equipment 130 illustrated in Figure 3A is for illustrative purposes only. Other configurations with more, fewer, or a different arrangement of components may be implemented. For example, in some implementations, the user equipment 130 may comprise, or be connected to a GPS position measuring device.

Figure 3B illustrates an exemplary implementation of the user equipment 130 in which the user equipment 130 comprises a cellular radiotelephone. As shown in Figure 3B, the user equipment 130 may comprise a microphone 335, e.g., of input device 320 for entering audio information into the user equipment 130, a speaker 340, e.g., of output device 325 for providing an audio output from the radiotelephone, a keypad 345, e.g., of input device 320 for manual entry of data or selection of telephone functions, and a display 350, e.g., of input device 320 or output device 325 that may visually display data to the user and/or which may provide a user interface that the user may use to enter data or to select telephone functions, in conjunction with keypad 345.

Figure 4 illustrates some signalling and processing steps according to some embodiments of the present solution. It is thus illustrated in Figure 4 how the continuous non-scheduled transmissions of the present methods may be used in order to transfer scheduling information and data, according to some optional embodiments. The illustration in Figure 4 is intended to explain some general principles behind the present methods, according to some embodiments. However, all the explained steps 410-430 may not necessarily be comprised within all embodiments of the present methods.

Step 410 The user equipment 130 sends its scheduling Information in the non-scheduling Enhanced Uplink Physical Channel (NS E-PUCH), to its base station 110, and the scheduling Information may arrive at the base station 1 10 successfully since the risk of access collision is reduced in comparison with prior art.

Step 420 After the base station 1 10 receives the scheduling Information from the user equipment 130, the base station 110 may allocate a transmission grant to the user equipment 130 in the Enhanced Dedicated Channel Absolute Grant Channel (E-AGCH), according to the scheduling algorithm used by the base station 110.

Step 430

When the user equipment 130 accepts the transmission grant, it may transfer its data on the scheduled Enhanced Uplink Physical Channel (E-PUCH).

In some embodiments, it is the control node 140, shown in Figure 1 which may configure the user equipment 130 to transmit continuously in a non-scheduled uplink channel. For example, the continuous transmissions may be such that they take place in each Transmission Time Interval (TTI) of the user equipment 130, one TTI being equal to a multiple of sub-frames in a TD-SCDMA system. However, alternatively the continuous transmissions may be such that they take place in every several TTI of the user equipment 130, e.g. every second TTI, every third TTI, every fourth TTI etc.

The transmissions mentioned above of a bit stream of a pre-defined format may take place e.g. when there is no scheduling information or data traffic for the user equipment 130 to transmit to the Node B, in order to enable continuous transmission from the user equipment 130.

The continuous transmissions of the user equipment 130 in a non-scheduled uplink channel may also be used by the wireless communication system 100 in order to obtain other advantages. One such advantage may be that the base station 110 may use the continuous uplink transmissions from the user equipment 130 for uplink synchronization, i.e. the base station 110 may use the continuous uplink traffic in order to time-control transmissions from the user equipment 130.

This may be described in more detail as follows: in a TD-SCDMA system such as the one the invention is intended for, the base station 1 10 controls the user equipment 130 uplink "transmission advance" to make the signals from all of the user equipments 130 within the cell arrive at the base station 110 antenna at the same time, i.e. "uplink synchronization". The base station 110 may send adjustment commands to the user equipment 130, for adjusting the transmission power of the user equipment 130. The commands may be generated based on measurements made by the base station 110 of the uplink time difference to the different user equipments 130. By means of an uplink which is used for continuous transmissions, the base station 110 may be able to measure the time difference and may thus generate the power adjustment commands to the user equipment 130. The continuous uplink channel for the measurement may, in the present case, be the non-scheduled transmission of e.g. the E-PUCH.

Another advantage which may be gained by means of the continuous transmission of the present methods may be that if the base station 110 is equipped with an antenna 230 that is capable of so called beam-forming, the continuous user equipment uplink transmissions may be used as a pilot signal in order to direct the beams of the antenna 230 towards the user equipment 130.

Thus in, for example, a TD-SCDMA system, the downlink channels, with the exception of some common channels, may be beam formed. There may be beam forming algorithms in the base station antenna 230 which need a pilot signal in the uplink, so that the base station 1 10 may estimate the direction towards a user equipment 130, and transmit the downlink channels in a beam centred in that direction.

Figure 5 is a flow chart illustrating a method in a base station 1 10, for receiving information from a user equipment 130. The base station 110 and the user equipment 130 are comprised within a wireless communication system 100 and adapted to exchange wireless signals. The wireless communication system 100 is adapted to operate according to the Time Division Duplex, TDD principle.

The wireless communication system 100 may be e.g. a Time Division Synchronous Code Multiple Access system, a TD-SCDMA system, according to some embodiments. The base station 110 may in at least those embodiments be represented by a NodeB.

The non-scheduled uplink channel of the wireless communication system 100 may according to some embodiments be represented by the non-scheduled Enhanced Physical Uplink Channel, E-PUCH. However, according to some embodiments, the non-scheduled uplink channel of the wireless communication system 100 may be represented by the Dedicated Physical Channel, DPCH.

To appropriately receive the information from a user equipment 130, the method may comprise a number of steps 510-550. It is however to be noted that some parts of the described method steps are optional and only comprised within some embodiments. Further, it is to be noted that the method steps 510-550 may be performed in any arbitrary chronological order and that some of them, or even all method steps may be performed simultaneously or in an altered, arbitrarily rearranged, decomposed or even completely reversed chronological order. The method comprises the following steps:

Step 510

Scheduling information is received from the user equipment 130 in a non-scheduled uplink channel of the wireless communication system 100.

According to some optional embodiments, the scheduling information may be received continuously from the user equipment 130, in a non-scheduled uplink channel of the wireless communication system 100.

According to some optional embodiments, the scheduling information may be received continuously from the user equipment 130 per every Transmission Time Interval, TTI, or per every several TTI in a non-scheduled uplink channel of the wireless communication system 100.

Step 520

This method step is optional and may be performed only according to some embodiments. A grant may be allocated to the user equipment 130. The grant may further be sent to the user equipment 130.

Step 530

This method step is optional and may be performed only according to some embodiments. Information may be obtained from the user equipment 130 in a non-scheduled uplink channel of the wireless communication system 100, wherein the information may comprise data traffic and/ or a bit stream according to a pre-defined format. According to some optional embodiments, the information may be obtained continuously from the user equipment 130, in a non-scheduled uplink channel of the wireless communication system 100.

According to some optional embodiments, the information may be obtained continuously from the user equipment 130 per every Transmission Time Interval, TTI, or per every several TTI in a non-scheduled uplink channel of the wireless communication system 100.

Step 540

This method step is optional and may be performed only according to some embodiments. The user equipment 130 may be synchronized with other user equipments within the same cell 120, based on the received information. Thus signals from all user equipments within the cell 120 may be received simultaneously by the base station 110.

Thus the base station 110 according to some embodiments may use the continuous uplink transmissions from the user equipments in the cell 120, e.g. the user equipment 130, for uplink synchronization, i.e. the base station 110 may use the continuous uplink traffic in order to time-control transmissions from the user equipments in the cell 120.

Step 550

This method step is optional and may be performed only according to some embodiments. The antenna 230 of the base station 110 may be beam-formed based on the received information.

Thus according to some embodiments, the base station 110 may be equipped with at least one antenna 230, capable of so called beam-forming. The continuous uplink transmissions from the user equipment 130 may be used as a "pilot signal" in order to direct the beams of the antenna towards the user equipment 130.

To perform the method steps above, the base station 110 comprises an arrangement 600, depicted in Figure 6. The arrangement 600 is adapted to receive information from a user equipment 130. The base station 110 and the user equipment 130 are comprised within a wireless communication system 100 and adapted to exchange wireless signals. The wireless communication system 100 is adapted to operate according to the Time Division Duplex (TDD) principle.

The arrangement 600 comprises a receiving unit 610. The receiving unit 610 is adapted to receive scheduling information from the user equipment 130 in a non-scheduled uplink channel of the wireless communication system 100.

The arrangement 600 may, according to some optional embodiments, comprise an allocating unit 620. The allocating unit 620 may be adapted to allocate a grant to the user equipment 130.

Also, according to some embodiments, the arrangement 600 in a base station 110 may comprise a sending unit 625. The sending unit 625 may be configured for sending signals to be received e.g. by the user equipment 130.

Further, according to some embodiments, the arrangement 600 may comprise an obtaining unit 630. The obtaining unit 630 may be adapted to obtain information from the user equipment 130 in a non-scheduled uplink channel of the wireless communication system 100. The information may comprise data traffic and/ or a bit stream according to a pre-defined format.

According to some embodiments, the arrangement 600 may comprise a synchronizing unit 640. The synchronizing unit 640 may be adapted to synchronize the signals sent from the user equipment 130 with signals sent from other user equipments within the cell 120, based on the received information.

Further, according to some embodiments, the arrangement 600 may comprise an antenna 230. The antenna 230 may be configured for beam forming, which beam forming may be performed based on the previously received information from the user equipment 130.

It is to be noted that any internal electronics of the base station 110 not completely necessary for performing the present method according to the method steps 510-550, such as e.g. some of the internal electronics of the base station depicted in Figure 2, has been omitted from Figure 6, for clarity reasons. The allocating unit 620, the obtaining unit 630 and/or the synchronizing unit 640, which optional units may be comprised within some embodiments of the arrangement 600 in the base station 110 may be a processing unit, a CPU or any logic machine with ability to execute a computer program.

It is to be noted that the described units 610-650 comprised within the arrangement 600 in the base station 110 are to be regarded as separate logical entities but not with necessity separate physical entities. Any, some or even all of the units 610-650 may be comprised or co-arranged within the same physical unit. However, in order to facilitate the understanding of the functionality of the arrangement 600 in the base station 110, the comprised units 610-650, of which some units 620-650 are optional and only comprised within some embodiments, are illustrated as separate physical units in Figure 6.

Thus e.g. the optional sending unit 625 and e.g. the receiving unit 610 may, according to some embodiments, be comprised within one physical unit, a transceiver, which may comprise a transmitter circuit and a receiver circuit, which respectively transmits outgoing radio frequency signals to the user equipment 130 and receives incoming radio frequency signals from the user equipment 130 via an antenna 230. The antenna 230 may be an embedded antenna, a retractable antenna or any antenna known to those having skill in the art without departing from the scope of the present invention. The radio frequency signals transmitted between the user equipment 130 and the base station 1 10 may comprise both traffic and control signals e.g., paging signals/messages for incoming calls, which may be used to establish and maintain a voice call communication with another party or to transmit and/or receive data, such as SMS, e-mail or MMS messages, with another remote user equipment.

The base station 110 may, according to some embodiments, be represented by a NodeB and may be adapted to operate e.g. in a TD-SCDMA system.

Figure 7 is a flow chart illustrating a method in a user equipment 130 for sending information to a base station 110. The user equipment 130 and the base station 110 are comprised within a wireless communication system 100. The user equipment 130 and the base station 110 are also adapted to exchange wireless signals. The wireless communication system 100 is adapted to operate according to the TDD principle. The wireless communication system 100 may be e.g. a Time Division Synchronous Code Multiple Access system, a TD-SCDMA system, according to some embodiments. The base station 110 may in at least those embodiments be represented by a Node B.

5 The non-scheduled uplink channel of the wireless communication system 100 may according to some embodiments be represented by the non-scheduled Enhanced Physical Uplink Channel, E-PUCH.

However, according to some embodiments, the non-scheduled uplink channel of the 10 wireless communication system 100 may be represented by the Dedicated Physical Channel, DPCH.

To appropriately send the information to the base station 110, the method may comprise a number of steps 710-730. It is however to be noted that some parts of the described

15 method steps are optional and only comprised within some embodiments. Further, it is to be noted that the method steps 710-730 may be performed in any arbitrary chronological order and that some of them, or even all method steps may be performed simultaneously or in an altered, arbitrarily rearranged, decomposed or even completely reversed chronological order. The method comprises the following steps:

20

Step 710

Scheduling information is sent to the base station 110 in a non-scheduled uplink channel of the wireless communication system 100.

25 According to some embodiments, the scheduling information may be sent continuously to the base station 110 per every TTI or per every several TTI.

Step 720

According to some optional embodiments a grant may be received from the base station 30 110.

According to some embodiments the user equipment 130 has to firstly accept the grant before proceeding with the next method step.

35 Step 730 This step is optional and may only be performed in some embodiments. Information may be transmitted to the base station 110 in a non-scheduled uplink channel of the wireless communication system 100. The information may comprise data traffic and/ or a bit stream according to a pre-defined format.

According to some embodiments, the information may be sent continuously to the base station 110 per every TTI or per every several TTI.

According to some embodiments, the transmission of a bit stream may take place when there is no scheduling information or data traffic to transmit to the base station 110.

To perform the method steps above, the user equipment 130 comprises an arrangement 800, depicted in Figure 8. The arrangement 800 is adapted to send information to a base station 110. The base station 110 and the user equipment 130 are comprised within a wireless communication system 100 and adapted to exchange wireless signals. The wireless communication system 100 is adapted to operate according to the TDD principle.

The arrangement 800 comprises a sending unit 810. The sending unit 810 is adapted to send scheduling information to the base station 110 in a non-scheduled uplink channel of the wireless communication system 100.

According to some optional embodiments, the arrangement 800 may comprise a receiving unit 820. The receiving unit 820 may be adapted to receive signals e.g. from the base station 110.

According to some optional embodiments, the arrangement 800 in a user equipment 130 may comprise a processing unit 830. The processing unit 830 may according to some embodiments be e.g. a CPU or any logic machine with ability to execute a computer program.

It is to be noted that any internal electronics of the user equipment 130 not completely necessary for performing the present method according to the method steps 710-730, such as e.g. some of the internal electronics of the base station depicted in Figure 3A and 3B, has been omitted from Figure 8, for clarity reasons. It is further to be noted that the described units 810-830 which units may be comprised within the arrangement 800 in the user equipment 130 are to be regarded as separate logical entities but not with necessity separate physical entities. Any, some or even all of the units 810-830 may be comprised or co-arranged within the same physical unit. However, in order to facilitate the understanding of the functionality of the arrangement 800 in the user equipment 130, the comprised units 810-830, of which e.g. the unit 820 and 830 are optional and only comprised within some embodiments, are illustrated as separate physical units in Figure 8.

Thus e.g. the optional receiving unit 820 and e.g. the sending unit 810 may, according to some embodiments, be comprised within one physical unit, a transceiver, which may comprise a transmitter circuit and a receiver circuit, which respectively transmits outgoing radio frequency signals to the base station 1 10 and receives incoming radio frequency signals from the base station 110 via an antenna. The antenna may be an embedded antenna, a retractable antenna or any antenna known to those having skill in the art without departing from the scope of the present invention. The radio frequency signals transmitted between the user equipment 130 and the base station 110 may comprise both traffic and control signals e.g., paging signals/messages for incoming calls, which may be used to establish and maintain a voice call communication with another party or to transmit and/or receive data, such as SMS, e-mail or MMS messages, with another remote base stations.

The user equipment 130 may, according to some embodiments, be adapted to operate e.g. in a TD-SCDMA system.

Some particular embodiments

Figure 9 illustrates a method 900 according to some embodiments. According to these embodiments, the method 900 is used in a wireless cellular communications system 100.

The method 900 operates 910 according to the Time Division Duplex (TDD) principle. Thus transmission and reception are carried out in time frames, each of which frame is divided into a number of time slots. The system 100 comprises at least a first controlling transceiver 110.

The system 100 have the ability to comprise a number of user terminals 130 within a first geographical area 120 in the system. The controlling receiver 110 serve to control the traffic to ("downlink") and from ("uplink") the user terminals 130 in the first geographical area 120. The uplink traffic within the system 100 may comprise both scheduled and non-scheduled traffic. The scheduled uplink traffic is preceded by uplink scheduling information. The method 900 is characterized in that 915 at least a number of user terminals 130 in the system 100 are configured to transmit continuously in the non-scheduled uplink channel of the system 100. The transmissions involve at least one of the following: some of said scheduling information 920, data traffic 925, a bit stream according to a pre-defined format 930.

The method 900, 935 may according to some embodiments, according to which the transmission of a bit stream takes place when there is no scheduling information or data traffic to transmit from the user terminal 130.

The continuous transmissions may take place in each Transmission Time Interval 940, TTI, or in every several TTI, of the user terminals 130, according to some embodiments.

The continuous transmissions may, according to some embodiments be used for uplink synchronization 945 by the first transceiver 110, i.e. the first transceiver 110 may use the continuous uplink traffic in order to time-control transmissions from the user terminals 130.

The first transceiver 110 may, according to some embodiments, be equipped with an antenna capable of beam forming 950, and the continuously transmitted information may be used as a "pilot signal" in order to direct the beams of the antenna to the user terminals 130.

The method 900, 960 may, according to some embodiments be applied to a Time Division Synchronous Code Multiple Access system, a TD-SCDMA system, in which system the controlling node 110 is a Node B in the system.

According to some embodiments 965, the non-scheduled uplink channel of the system may be the non-scheduled Enhanced Physical Uplink Channel, the E-PUCH.

According to some embodiments 965, the non-scheduled uplink channel of the system is the Dedicated Physical Channel, DPCH.

Figure 10 illustrates a user terminal 130, 1000 according to some embodiments. The user terminal 130, 1000 is used in a wireless cellular communications system 100. The wireless cellular communications system 100 operates according to the Time Division Duplex, TDD, principle. Thus the user terminal 130 comprises means for transmission 1010, 1030, 1040 and reception 1010, 1020, 1040 in time frames. The time frames are divided into a number of time slots.

The user terminal 130, 1000 comprises means 1010, 1020, 1030, 1040 for transmitting both scheduled and non-scheduled traffic.

The scheduled uplink traffic may be preceded by uplink scheduling information, the user terminal 130 may comprise means 1030, 1040 which make it configurable for transmitting continuously in a non-scheduled uplink channel of the system 100.

The transmission may involve at least one of the following: some of said scheduling information 920, data traffic 925, bit stream according to a pre-defined format 530.

The user terminal 130, 1000 may, according to some embodiments comprise transmission means 1010, 1030, 1040 which enable transmission of a bit stream to take place when there is no scheduling information or data traffic to transmit from the user terminal 130, 1000.

The transmission means 1010, 1030, 1040 may enable the continuous transmissions to take place continuously per each Transmission Time Interval, TTI, or per each several TTI, according to some embodiments.

The user terminal 130, 1000 may, according to some embodiments, be comprised within a Time Division Synchronous Code Multiple Access system, a TD-SCDMA system.

The non-scheduled uplink channel of the system 100 may according to some embodiments be a non-scheduled Enhanced Physical Uplink Channel, E-PUCH.

The non-scheduled uplink channel of the system 100 may according to some embodiments be a Dedicated Physical Channel, DPCH.

Yet some particular embodiments

The present methods for sending and/or receiving information may be implemented through one or more processors in the base station 110 and user equipment 130, together with computer program code for performing the functions of the present method. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the methods according to the respective method steps when being loaded into the processor unit. The data carrier may be e.g. a CD ROM disc, a memory stick, or any other 5 appropriate medium such as a disk or tape that can hold machine readable data. The computer program code may furthermore be provided as pure program code on a server and downloaded to the base station 110 and/or user equipment 130 remotely.

Thus a computer readable medium encoded with a computer program for receiving 10 information may perform the method according to at least some of the method steps 510- 550.

Thus a computer readable medium encoded with a computer program for sending information may perform the method according to at least some of the method steps 710- 15 730.

The invention is not limited to the examples of embodiments described above and shown in the drawings, but may be freely varied within the scope of the appended claims. Thus, the invention may be applied to other TDD systems than the TD-SCDMA system, which has 20 been used in the description above and in the drawings in order to facilitate the reader's understanding of the invention.

Claims

1. Method in a base station (110), for receiving information from a user equipment (130), the base station (110) and the user equipment (130) are comprised within a wireless communication system (100) and adapted to exchange wireless signals, the wireless communication system (100) is adapted to operate according to the Time Division Duplex, TDD principle, the method comprises the step of: receiving (510) scheduling information from the user equipment (130) in a non- scheduled uplink channel of the wireless communication system (100).

2. Method according to claim 1 , further comprising the step of: allocating (520) a grant to the user equipment (130).

3. Method according to claim 1 or 2, further comprising the step of: obtaining (530) information from the user equipment (130) in a non-scheduled uplink channel of the wireless communication system (100), wherein the information comprises data traffic and/ or a bit stream according to a pre-defined format.

4. Method according to any of the claims 1-3, wherein the step of receiving (510) and/or the step of obtaining (530) is performed continuously, per every Transmission Time Interval, TTI, or per every several TTI.

5. Method according to any of the claims 1-4, further comprising the step of: synchronizing (540) the user equipments (130), based on the received information.

6. Method according to any of the previous claims 1-5, wherein the base station (110) comprises an antenna (230) configured for beam forming and wherein the method further comprises the step of: beam forming (550) the antenna (230) based on the received information.

7. Method according to any of the previous claims 1-6, wherein the wireless communication system (100) is a Time Division Synchronous Code Multiple Access system, a TD-SCDMA system, and the base station (110) is represented by a Node B.

8. Method according to any of the previous claims 1-7, wherein the non-scheduled uplink channel of the wireless communication system (100) is represented by the non- scheduled Enhanced Physical Uplink Channel, E-PUCH.

5 9. Method according to any of the previous claims 1-7, wherein the non-scheduled uplink channel of the wireless communication system (100) is represented by the Dedicated Physical Channel, DPCH.

10. Arrangement (600) in a base station (110), which arrangement (600) is adapted to 10 receive information from a user equipment (130), the base station (110) and the user equipment (130) are comprised within a wireless communication system (100) and adapted to exchange wireless signals, the wireless communication system (100) is adapted to operate according to the Time Division Duplex, TDD principle, the arrangement (600) comprises:

15 a receiving unit (610), adapted to receive scheduling information from the user equipment (130) in a non-scheduled uplink channel of the wireless communication system (100).

11. Method in a user equipment (130), for sending information to a base station (110), 20 the user equipment (130) and the base station (110) are comprised within a wireless communication system (100) and adapted to exchange wireless signals, the wireless communication system (100) is adapted to operate according to the Time Division Duplex, TDD principle, the method comprises the step of: sending (710) scheduling information to the base station (110) in a non-scheduled 25 uplink channel of the wireless communication system (100).

12. Method according to claim 11 , further comprising the step of: receiving (720) a grant from the base station (110).

30 13. Method according to claim 11 or 12, further comprising the step of: transmitting (730) information to the base station (110) in a non-scheduled uplink channel of the wireless communication system (100), wherein the information comprises data traffic and/ or a bit stream according to a pre-defined format.

14. Method according to any of the claims 11-13, wherein the step of sending (710) and/or the step of transmitting (730) is performed continuously per every Transmission Time Interval, TTI, or per every several TTI.

15. Method according to any of the claims 11-14, wherein the transmission of a bit stream takes place when there is no scheduling information or data traffic to transmit to the base station (110).

16. Arrangement (800) in a user equipment (130), which arrangement (800) is adapted to send information to a base station (110), the user equipment (130) and the base station (110) are comprised within a wireless communication system (100) and adapted to exchange wireless signals, the wireless communication system (100) is adapted to operate according to the Time Division Duplex, TDD principle, the arrangement (800) comprises: a sending unit (810) adapted to send scheduling information to the base station

(110) in a non-scheduled uplink channel of the wireless communication system (100).