Uplink scrambling during random access

TECHNICAL FIELD

Field of the Invention relates to a mobile radio, in particular to the implementation of the uplink communication, involving mobile radio terminals in a mobile communications system.

BACKGROUND ART

Universal Mobile Telecommunications System (UMTS) is an asynchronous mobile communication system of the 3rd generation (3G), working using wideband code division multiple access (WCDMA), based on European systems, Global System for Mobile Communications (GSM) and packet radio General purpose (GPRS). Long Term Evolution (LTE) UMTS project partnership developed the 3rd generation (3GPP), which is standardized UMTS. There are many technical specifications, which are on the 3GPP website, evolutionary related Universal Terrestrial Radio Access (E-UTRA) and network evolution universal terrestrial radio access (E-UTRAN), e.g. 3GPP TS 36.300. Objective LTE is to develop a framework for the development of technology radio access 3GPP towards high data rate, low-latency and packet-optimized radio-access technology. In particular, LTE aims to support services provided in connection with packet switched (PS). The main purpose of 3GPP LTE technology is to provide high-speed packet communication rate of approximately 100 Mbit / s or higher.

1 illustrates an example mobile communications system 10 of the type LTE. E-UTRAN 12 includes nodes E-UTRAN NodeB (eNodeB, or eNB) 18, which provide completion protocol user plane and control plane for the E-UTRA user equipment (UE) 20 over the radio interface. Although eNB is a logical node, often but not necessarily implemented with a physical base station, the term "base station" is used herein to generally cover both logical and physical nodes. UE is sometimes referred to as a mobile radio terminal and it is in an idle state monitors system information transmitted to the eNB within a range to receive the base stantsiyah- "Candidate" in the service area. When a UE needs access to a radio access network, it sends a request on the random access channel (RACH) to the corresponding node eNB, typically to eNB with the most favorable radio conditions. Nodes eNB are connected with each other through X2 interface. eNB also connected through S1 interface to the core evolutionary batch system (EPC) 14 which includes a mobility management module (MME), using the S1-MME, and the gateway system architecture evolution (SAE) by S1-U. In this example, MME / SAE Gateway is referred to as a single node 22. S1 interface supports relations "many to many" between the MME / SAE gateways and eNB. E-UTRAN 12 and EPC 14 together form the land mobile network PSTN (PLMN). MME / SAE Gateways 22 are connected directly or indirectly to the Internet 16 and to other networks.

To enable operation at various distributions of frequency range, for example to ensure a smooth migration from existing cellular systems to the new high capacity high speed data transmission system in the existing radio spectrum, need to work in a flexible range of frequencies, for example in the frequency range between 1 , 25 MHz to 20 MHz for downlink transmissions from network to UE. It is necessary to maintain service and high speed data and low-speed services, such as voice, and because 3G LTE is designed for the protocol TCP / IP, speech transmission services will likely be VoIP.

Transfer uplink LTE is based on the so-called OFDM transmission with spread spectrum by discrete Fourier transform (DFTS-OFDM), a low ratio of peak to average power ratio (PAPR), with a transmission scheme of a single carrier (SC), which allows for free assignment of the frequency band, and orthogonal multiple access not only in time domain, but also in the frequency domain. Thus, a transmission scheme for LTE uplink is also often referred to as Single-Carrier FDMA (SC-FDMA).

Processing transport channel uplink LTE is shown in Figure 2. A transport block of dynamic size is delivered from the level of the medium access control data (MAC). Cyclic Redundancy Code (CEC), which will be used to detect errors in the base station receiver is calculated for the unit and is attached to it. Next, a channel encoding uplink via a channel encoder which may use any suitable coding technique. In LTE, the code may be a turbo code that includes a square-based permutation polynomial (QPP) internal interleaver for performing block interleaving as part of the turbo encoder. Hybrid automatic retransmission request (ARQ) uplink LTE removes from the block of coded bits delivered by the channel coder, the exact set of bits to be transmitted in every time transmission / retransmission. Block scrambling scrambles the coded bits in the LTE uplink (e.g., using a bit-level scrambling) to randomize the interference and thus to ensure full utilization of the processing gain provided by the channel code.

To ensure that interference randomization uplink scrambling is mobile terminal-specific, i.e. different mobile terminals (UE) use different scrambling sequences. Specific terminal scrambling also provides a scheduling unit (resource allocation), the ability to schedule multiple users on the same time-frequency resource division transmissions from the plurality of users based on the processing at the base station receiver. Specific terminal scrambling randomizes the interference from other mobile terminals in the same cell, which proved to be scheduled on the same resource and improves the performance.

After scramble data is modulated to convert the block of coded / scrambled bits into a block of complex modulation symbols. A set of modulation schemes supported for an uplink LTE, includes a quadrature phase shift keying (QPSK), 16-level quadrature amplitude modulation (16QAM) and 64-level quadrature amplitude modulation (64QAM), which correspond to two, four and six bits per modulation symbol, respectively. The block of modulation symbols is then applied to the modulator DFTS-OFDM, which also displays the signal on the assigned radio resource, such frequency subband.

Together with the data signal modulated symbols mapped to the assigned frequency band also contains demodulation reference signals. Reference signals known in advance and the mobile terminal (UE), and a base station (eNodeB) and are used by the receiver for channel estimation and data symbol demodulation. Different reference signals can be assigned to user terminals, for similar reasons, to be able to use typical of a terminal scrambling codes, ie, intelligently schedule multiple users on the same time-frequency resource and thereby realize so-called multi-user MIMO system (multiple-input multiple-output). In the case of multi-user MIMO systems eNodeB performs processing to separate the signals transmitted from the two (or more) UE, simultaneously scheduled on the same frequency resource in the same cell. Terminals, which are simultaneously scheduled on the same frequency resource, commonly assigned different (e.g., orthogonal) reference signal sequences to eNodeB evaluated radio channels for each of the UE.

A basic requirement for any cellular or other radio communications system is providing a user terminal to request a connection setup. This capability is commonly known as random access, and it corresponds to the two main purposes in LTE, namely, establishment of uplink synchronization with the timings of the base station and to establish a unique identification information of the user terminal, for example a temporary identifier cellular radio network (C-RNTI) in LTE , and form a network and a user terminal that is used when communicating to transmit data to distinguish the user from other data transmissions.

But during the (initial) random access procedure when transmitting on the uplink from the user terminal can not use typical terminal scrambling sequences or reference numbers to randomize interference because using the initial request message to the random access from the user terminal has just started communicating with network, and no specific scrambling code to a terminal or terminal specific reference number has not been assigned to this user terminal. A mechanism that allows to scramble random access messages sent over a shared uplink channel until a specific terminal scrambling code can not be assigned to the user terminal. One reason for scrambling the random access message is the randomization of interference between cells, which is also a cause for scrambling during "normal" data transmission on the uplink. In the latter case, scrambling can also be used to suppress intra-cell interference in case of multiple UE, scheduled for the same time-frequency resource. Similarly, it is desirable that the user terminals transmit known reference signals during random access to allow the base station receiver to estimate the uplink channel. It is necessary that the random access message, and the "normal" transmission of the uplink data including the reference signal to allow channel estimation at the eNodeB and corresponding coherent demodulation.

DISCLOSURE OF INVENTION

Described below technology provides random access by using the user terminal to the base station. A user terminal determines one of scrambling sequences uplink of the first type, and generates a random access message using the determined one of scrambling sequences uplink first type. Its transmitter transmits the random access message to the base station. A user terminal receiver then receives from the base station scrambling sequence uplink differs second type. The terminal uses the scrambling sequence of uplink second type differs for subsequent communication with the radio base station. In one non-limiting exemplary embodiments of the scrambling sequence uplink of the first type can be associated with a specific area of ​​a cell base station or to a particular radio link random access associated with base station, but they are not specifically assigned to any user terminal, and scrambling sequence ascending characterized a second link type may be selected from a second set of scrambling sequences uplink assigned to specific user terminals. Using these two scrambling sequences differing types allows user terminals to scramble their transmissions the uplink signal, even though the characteristic of the terminal scrambling codes can not be used in the uplink during random access by user terminals.

The user terminal transmits a first random access request message including a random access preamble to a base station using a radio resource of the random access channel. Then, receiving from the second base station the random access response message that indicates an adjustment timing, the identified radio resource, and a temporary user terminal identifier. The terminal corrects the timing of the user terminal to transmit signals to the base station, based on information received in a random access response, and based on the adjusted timing, transmits a third message corresponding to the generated random access message including the full identification information user terminal to the base station on the identified radio resource. The third message is scrambled using the determined one of scrambling sequences uplink first type is modulated and mapped to a radio channel resource. The terminal receives a fourth message to resolve conflicts between the radio base station to complete the random access procedure, and then follows the usual communicating.

Various non-limiting embodiments of the first display set of scrambling sequences to the uplink some other parameter known to the user terminal and the base station. For example, a first set of scrambling sequences uplink may be mapped to corresponding random access preamble sequences. One of the first set of scrambling sequences uplink may then be selected based on the random access preamble, which includes a first random access request message, and this mapping. Another example maps the first set of scrambling sequences in uplink corresponding user terminal identifiers and selects one of the first set of scrambling sequences uplink based on the user terminal identifier included in the second random access response message, and this mapping. The third example shows the first set of scrambling sequences uplink corresponding radio resources used for transmitting a random access request, and selects one of the first set of scrambling sequences uplink based on radio resource random access channel used for transmission to the base first communication station the random access request, which includes the random access preamble, and for this mapping.

Suitable scrambling sequences of the two types may also be used for reference signals, implemented in random access message uplink sent from the base station that are used by the base station to estimate the uplink channel, for example, in order to equalize etc. Selecting one of a first set of reference sequences uplink reference sequences e.g. uplink that are associated with a particular area of ​​the cell or the radio base station with a particular random access channel but which are not specifically assigned to any of the user terminals. Generating a random access message using the selected one of the first set of scrambling sequences uplink and a selected one of a first set of reference sequences uplink. The user terminal transmits a random access message to the base station. Thereafter, the base station informs the user terminal of the second reference sequence differing type for use in the subsequent implementation uplink, e.g., a reference number assigned specifically to this user terminal.

In one non-limiting exemplary embodiments of the user terminal and a base station configured to communicate with the radio system long term evolution (LTE) using the user terminal transmitting the first message the random access request on the random access channel (RACH), and the third connection - on a shared channel uplink (UL-SCH). User terminal identifier sent by the base station in the second message may be a temporary user terminal identifier used until a radio network terminal identifier is (RNTI) is assigned to the user terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is an example LTE mobile radio communication system;

2 is a block flowchart illustrating a non-limiting exemplary procedures for preparing a transport block delivered from the media access level data transmission of a user terminal for transmission over the radio interface to the network in the LTE mobile communications system;

3 is a block flowchart illustrating a non-limiting exemplary procedure, the user terminal to perform random access to the radio network;

4 is a block flowchart illustrating a non-limiting exemplary procedure for receiving and processing a random access base station from the user terminal to the radio network;

5A and 5B show a mapping between transport and physical channels in the downlink and uplink, respectively;

6 is a diagram illustrating three basic states of a user terminal;

7 is a signaling diagram which shows non-limiting exemplary procedure of random access;

8 shows a non-limiting example random access preamble transmission; and

9 is an exemplary non-limiting functional block diagram of the user terminal and the base station eNodeB.

THE INVENTION

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular nodes, functional modules, techniques, protocols, standards, etc. to provide an understanding of the described technology. In other instances, detailed descriptions of well-known methods, devices, techniques, etc. omitted so as not obscure the description with unnecessary detail. The figure shows separate functional blocks. Professionals should recognize that the functions of those blocks may be implemented using individual hardware circuits, using software and data together with a suitably programmed microprocessor or general purpose computer, using application specific integrated circuits (ASICs), programmable logic arrays and / or using one or more processors Digital Signal Processing (DSP).

Those skilled will appreciate that other embodiments can be implemented independently from the specific details disclosed below. The technology described in the context of UMTS 3GPP evolution system, such as LTE, for indicative and non-limiting context for explanation. See., E.g., LTE scheme system, shown in Figure 1. But this technology is not limited to LTE and may be used in any modern radio communications system. In addition, the following approach, which uses the two scrambling sequences of different types - one for random access and one for communications after random access, - can also be applied to known channel estimation reference signals (sometimes called pilot signals). However, the detailed explanation provided using scrambling sequences with the understanding that similar details apply to reference signals. For ease of description, user equipment (UE) is often referred to without limitation as a user terminal or a mobile terminal and eNodeB relates to the use of the more general and familiar term "base station".

3 is a block flowchart illustrating a non-limiting exemplary procedure, the user terminal to perform random access to the radio network, using the scrambling code for the uplink, which is generally available to all user terminals that need to receive the service in the random access specific cell . The user terminal detects the scrambling sequence of uplink first type of scrambling sequence example of uplink associated with a particular area of ​​the cell or the radio base station with a particular random access channel but which are not specifically assigned to any user terminal (step S1). Determine a selected one of scrambling sequences uplink of the first type (step S2) and generates a random access message using the selected one of scrambling sequences uplink of the first type (step S3). The user terminal transmits a random access message to the base station (step S4). After transmitting the random access message, the user terminal receives from the base station scrambling sequence uplink second type characterized, for example scrambling sequence uplink selected from a second set of scrambling sequences uplink assigned to specific user terminals (step S5). The user terminal uses the scrambling sequence of uplink second type for subsequent communication with the radio base station. Similar procedures can be used for the known reference signal of the uplink.

4 is a block flowchart illustrating an exemplary non-limiting similar procedures for reception and processing by the base station the random access of the user terminal to the radio network. Each base station in the network has its own set of preamble sequences, reference signals, and non-terminal specific scrambling codes or sequences. The base station transmits, implicitly or explicitly, for example, broadcast channel BCH and its own set of preamble scrambling sequences uplink (step S10). If the base station transmits clearly scrambling sequence to be used, it sends the identification information of the cell from which the scrambling sequence to use may be prepared, for example via a mapping between sequence and cell identifier. Scrambling sequences uplink may be, for example, associated with a particular area of the cell or the radio base station with a particular random access channel and are not specifically assigned to any user terminal. The base station then waits for the reception of the first random access request message from the user terminal that includes one of the base station preambles. In response, the base station transmits to one of the user terminals, the second message is a random access response indicating a timing correction, the identified radio resource and an identifier of the user terminal. A third message corresponding to the generated random access message that includes identifying information of the user terminal, is descrambled using the selected one of the first set of scrambling sequences uplink (step S11). Thereafter, the base station transmits to the user terminal a fourth message including the scrambling sequence uplink differs second type selected, e.g., from a second set of scrambling sequences uplink. The scrambling sequence assigned uplink specific user terminals (step S12). The user terminal uses the second scrambling sequence uplink for subsequent communication with the radio base station. Similar procedures can be used for the known reference signal of the uplink.

To better understand the subsequent non-limiting exemplary and LTE random access procedure, refer to Figures 5A and 5B, which show a mapping between transport and physical channels in the downlink and uplink, respectively. The following transport channels are downlink channels: a broadcast channel (BCH), paging channel (PCH), the shared downlink channel (DL-SCH) and multicast channel (MCH). BCH are mapped to the physical broadcast channel (PBCH), and the PCH and DL-SCH are mapped to a physical shared downlink channel (PDSH). The transport channels of the uplink include a random access channel (RACH) and a shared uplink channel (UL-SCH). RACH are mapped to the physical random access channel (PRACH), and UL-SCH are mapped to a shared physical uplink channel (PUSCH).

In LTE, like in other mobile radio systems, the mobile terminal can be in several different operational states. 6 shows the states for LTE. At power up, the mobile terminal enters the state LTE_DETACHED (unconnected state). In this state, the mobile terminal is not known to the network. Before the further implementation of communication can take place between the mobile terminal and the network, the mobile terminal has to register with the network using a random access procedure to enter the state LTE_ACTIVE (active state). LTE_DETACHED state is mainly a state used at power-up. When the mobile terminal is registered to a network, it is usually in one of the other states: LTE_ACTIVE or LTE_IDLE (idle state).

LTE_ACTIVE is the state that is used when the mobile terminal is active with transmitting and receiving data. In this state, the mobile terminal is connected to a specific cell within the network. The mobile terminal is assigned one or more addresses of Internet Protocol (IP) address or other type of packet data as well as identifying information of the terminal, cell radio network temporary identifier (C-RNTI), used for the exchange of signals between the mobile terminal and the network. LTE_ACTIVE state includes two substates, IN_SYNC and OUT_OF_SYNC, depending on whether the uplink is synchronized to the network communication or not. While the uplink is in IN_SYNC, possible user data transmission on the uplink control signals and exchange the lower layer. If the transmission in the uplink does not occur within a given time window, then declare that the uplink is out of sync, in this case, the mobile terminal must perform a random access procedure to restore uplink synchronization.

LTE_IDLE is a state with low activity, in which the mobile terminal is idle most of the time to reduce battery consumption. Uplink synchronization is not maintained, and therefore, the only activity on the transfer of the uplink, which may occur, is random access to move to LTE_ACTIVE. The mobile terminal keeps its IP-address (es) and other internal information to jump in LTE_ACTIVE, when necessary. Location of the mobile terminal is partially know the network so that the network knows at least the group of cells in which it is necessary to perform paging of the mobile terminal.

A non-limiting exemplary procedure of the random access shown in Figure 7 and includes four steps referred to steps 1-4 with four corresponding signaling messages called messaging 1-4. The base station transmits a set of preambles associated with that base station, RACH resource information, and other information in a broadcast message sent regularly over a broadcast channel, which is regularly scanned active mobile terminals. In the first phase after the user terminal receives and decodes the information transmitted by the base station (eNodeB), it selects one random access preamble from the BS and transmits it on the RACH. The base station monitors the RACH and detects the preamble which allows the base station to estimate the timing of the transmission of the user terminal. Uplink synchronization is required to allow the terminal to transmit data to the base station on the uplink.

The random access preamble includes a known sequence, randomly selected by the mobile terminal from a set of known preamble sequences available for random access to a particular base station. By performing a random access attempt, the terminal selects one preamble sequence at random from the set of preamble sequences allocated to a cell to which the terminal is trying to contact. Until no other terminal is performing a random access attempt using the same preamble sequence at the same time, no conflicts arise and it is very likely that the random access request is detected by the base station. The user terminal transmits a preamble on a radio channel resources, such as time-frequency resource, assigned for random access, e.g., RACH.

8 illustrates conceptually a random access preamble transmission according to the LTE specification, both herein. One non-limiting examples of generation of the corresponding preamble sequence based on Zadofa-Chu (ZC) and its cyclic shifted sequences. Zadofa-Chu sequences may also be used, for example, to generate a reference signal of the uplink, which includes each data frame for channel estimation.

The user terminal performing a random access attempt, before transmitting the preamble received downlink synchronization from a cell search procedure using timing information transmitted by the base station. But, as explained above, the timing of the uplink is not yet established. Starting transmission frame on the uplink in the terminal is determined with respect to the frame transmission of downlink in the terminal. Because the propagation delay between the base station and the terminal the transmission of the uplink is delayed relative to the transmission timing of the downlink at the base station. Since the distance between the base station and the terminal is not known, there is an uncertainty in the timing of the uplink, which corresponds to twice the distance between the base station and the terminal. To account for this uncertainty and to avoid interference with the subsequent sub-frames are not used for random access, use the security slot.

Returning to the second stage of the exchange of signals of the random access shown in Figure 7, in response to the detected random access attempt, the base station 2 transmits a response to the random access request on a shared downlink channel (DL-SCH). Message 2 contains an index or other identifier of the random access preamble that the base station detected and for which the response is valid, the correction of the timing of the uplink command or forward timing calculated by the base station after processing the received random access preamble, the provision of resource allocation indicating resources the user terminal shall use for the transmission of messages in the third message sent from the mobile station to the base station, and a temporary user terminal identifying information used for subsequent communication between the user terminal and the base station. After step 2 is completed, the user terminal is synchronized in time.

If the base station detects a plurality of random access attempts (from different user terminals), then the response message 2 of the random access for multiple mobile terminals can be combined into a single transmission. Therefore, message 2 response to the random access plan on the DL-SCH and indicated on the physical control channel downlink (PDCCH), using common identifying information reserved for random access response. PDCCH is a control channel used to inform the terminal about whether there are the data on DL-SCH, intended for that terminal, and if so, at what time-frequency resource can find the DL-SCH. All user terminals that transmitted a preamble monitor the PDCCH for the presence of a random access response transmitted using the predefined common identity information used by the base station for all random access responses.

In the third step 3, the user terminal transmits the necessary information in message 3 to the network using the specified uplink resources assigned in message 2 of the random access response and synchronized in the uplink. Transfer uplink message in step 3 in the same manner as a "normal" scheduled uplink data, i.e. on UL-SCH, instead of attaching it to the preamble in the first phase, which is, for several reasons. Firstly, the amount of information transmitted in absence of uplink synchronization, communication must be minimized as the need for large guard time makes such transmissions range relatively expensive. Secondly, the use of "normal" transmission scheme on the uplink for transmitting messages allows to adjust the magnitude and modulation scheme of allocating resources, for example, depending on the different radio conditions. Third, it provides the possibility of combining the hybrid ARQ with software for uplink message which may be valuable, especially in scenarios limited coverage, as it helps to ensure that one or more retransmissions collect sufficient energy for the exchange of signals via uplink connection to ensure a sufficiently high probability of successful transmission. The mobile terminal transmits its temporary mobile terminal identification information such as the temporary C-RNTI, in the third step to the network using the UL-SCH. The exact contents of the message depends on the state of the terminal, such as whether it is previously known to the network or not.

Until terminals that perform random access at the same time use different preamble sequences, a conflict situation arises. But there is a potential for conflict when multiple terminals use the same random access preamble at the same time. In this case, multiple terminals react to the same response message is a downlink in step 2 and step 3 conflict situation arises. Conflict resolution is performed in step 4.

In step 4, conflict resolution message is transmitted from the base station to the terminal on DL-SCH. In this step to resolve conflicts in the case where a plurality of terminals attempt to access the system on the same resource, by identifying which of the user terminals was detected in the third step. Multiple terminals performing simultaneous random access attempts using the same preamble sequence in step 1, was analyzed the same response message in step 2 and, therefore, have the same temporary user terminal identifier. Thus, in step 4, each terminal receiving the downlink message compares the user terminal identifying information in the message with the user terminal identification information that they transmit in the third step. Only a user terminal, in which there is a correspondence between the identification information received in the fourth step, and the identification information is transmitted as part of the third step determines the random access procedure as successful. If the terminal is not yet assigned C-RNTI, the temporary identification information from the second stage is advanced into the C-RNTI; otherwise the user terminal retains its already assigned C-RNTI. Terminals which do not find a match with the identification information received in the fourth step must restart the random access procedure from the first step.

As explained above, the user terminal identifying information, which includes the message 3 is used as part of the conflict resolution mechanism in the fourth step. Continuing the discussion of non-limiting LTE example, if the user terminal is in the LTE_ACTIVE state, i.e. is connected to a known cell and therefore has a C-RNTI assigned, this C-RNTI is used as identification information of the terminal in an uplink message. Otherwise, the terminal identifier of the core network connection and the base station needs to involve the core network prior to connection response to an uplink message on the third stage.

In this non-limiting LTE example, only the first step uses physical layer processing specifically designed for random access. The last three steps use the same physical layer processing as in the "normal" transmission of the uplink signal and the downlink, which simplifies implementation and terminal and the base station. Because the transmission scheme used for data transmission, is designed to provide greater versatility of frequency bands and larger capacity, it is desirable to take advantage of these features also when exchanging random access messages.

In an exemplary non-limiting LTE context, the general processing steps described in Figure 2 including CRC, coding, HARQ, scrambling, modulation, and modulation of DFT-S-OFDM, is used by the user terminal to message 3 in Figure 7 and subsequent uplink transmissions from that user terminal to the base station (there is no scrambling in the initial random access message is an uplink in step 1). Different scrambling sequences uplink in the terminal depend on the type of uplink transmission. For message 3 of the random access scrambling sequence using a first type, a specific example for a cell-specific or random access channel scrambling code. For subsequent "normal" data transmission on the uplink, that is, when the base station is assigned to the terminal is not temporary identification information, a second type of scrambling sequence, such as a particular terminal scrambling code. A similar approach with two types can be used for reference signals of the uplink used by the base station for channel estimation: a first type, e.g., specific for a cell or specific for a random access channel reference signal to message 3 of the random access, followed by the second type, such as designated for base station or a reference signal sequence corresponding to the uplink for the next "normal" data transmission.

When the base station assigns the mobile terminal scrambling sequence and / or the reference sequence, this characteristic of the terminal scrambling sequence and / or reference sequence is used for all subsequent data transmission on the uplink for the particular compounds of the uplink. The scrambling sequence and / or reference sequence to be used, can either be explicitly configured in the mobile terminal, or may be attached to the terminal identification information (for example, C-RNTI), which a base station assigns the mobile terminal.

In the above case, the user terminal uses specific for a cell scrambling sequence to scramble message 3 because prior to performing random access, the user terminal decodes the broadcast information to base station / cell, and therefore knows the identification information of the cell to which it is drawn, the random access preamble related to this cell, and the cell characteristic of the scrambling sequence and / or reference numbers. Until multiple terminals performing random access at the same time are assigned different time frequency resources for their respective posts 3 random access uplink, there is no interference between these users and the lack of inter-user randomization is not a problem.

In a non-limiting embodiment, one mapping is introduced between the random access preamble sequence used in random access request message transmitted in step 1 in Figure 7 and the scrambling sequence used for scrambling the random access message sent in step 3. Because both the base station and the user terminal know the preamble used for the random access request message sent in step 1 by the time when the message 3 to be transmitted, both know which scrambling sequence to use.

In another non-limiting embodiment, the base station assigns the scrambling sequence for the user terminal to use for scrambling message 3 as a part of the response to the random access request transmitted in step 2 in Figure 7 (i.e., before sending the message 3). As one example, this can be done by establishing one-to-one mapping between the temporary user identifier sent in message 2, e.g. temporary C-RNTI, and the scrambling sequence to use.

Another non-limiting embodiment links the scrambling sequence to be used by the user terminal to scramble message 3, with the time-frequency resource (s) used by the user terminal for transmitting a random access preamble (message 1). In this case, the scrambling sequence will be known to both the base station and the user terminal because both know time-frequency resources used for the first random access request message. For this embodiment, the scrambling sequence will be shared between all user terminals transmitting a random access request preamble on the same time-frequency resource (s). But as long as all those terminals are assigned different time frequency resources for their own random access message 3, there is no interference between these users and the lack of inter-user randomization is not a problem.

It is also possible to use a combination of one or more of four different exemplary embodiments. Again, the principles described in the above scrambling sequence example and the four embodiments may also be used to reference numbers of the uplink used for estimating the uplink channel. In other words, one general or shared type of reference number may be used for message 3 of the random access uplink, and another terminal specific type reference number may be used for subsequent uplink communications associated with the connection.

There may be a situation where the user terminal has appointed identifying information, but he still has to perform random access. One example is when the terminal is registered in the network, but loses synchronization in the uplink, and therefore must perform a random access attempt to restore uplink synchronization. Although the user terminal is assigned identification information for the terminal specific scrambling can not be used for message 3 in this case, since the network does not know why the terminal is performing the random access attempt until message 3 is not received. As a result, it should be used associated with cell scrambling sequence, not an old characteristic of the terminal scrambling sequence.

Accordingly, an advantage of the characteristic of the terminal for scrambling for normal data is stored, without affecting the functionality of the random access procedure. As described above, a specific terminal scrambling randomizes interference which improves transmission performance on the uplink and provides additional flexibility in design planning.

While various embodiments are shown and described in detail, the claims are not limited by any of the specific embodiments or examples. For example, although primarily described in terms of scrambling sequences, the approach of the two types described for scrambling sequences of random access may also be used to determine the sequences of the reference signal sent in each uplink frame which are used by the base station receiver to estimate the uplink channel . None of the above description should not be construed as implying that any particular element, step, range, or function is basic, so that it should include the claims. Displacement of the claimed subject matter is defined only by the claims. The extent of legal protection is defined by the features set forth in the claims and received in their equivalents. All structural and functional equivalents to the elements of the above-described preferred embodiment that are known in the art, presented in this paper for reference, and encompassed by the present claims. Besides, it does not require a device or method to address each problem which seeks to solve with the present invention, in order to be covered by the present claims. None of the claims does not require the application of paragraph 6 §112 section 35, United States Code, if you do not use the words "means for" or "step for." Furthermore, none of the embodiments, features, components or steps herein are not intended to represent the public, regardless of whether the represented embodiment, feature, component or step in the claims.