MX2007001533A - Packet transmission acknowledgement in wireless communication system - Google Patents

Abstract

Transmitting an acknowledgement/negative acknowledgement (ACK/NACK) signal in association with a packet transmitted on an uplink is disclosed. The method includes the steps of receiving a packet transmitted from a user equipment, decoding the packet, and determining whether the packet has been successfully decoded, transmitting an ACK signal or a NACK signal, based on the decoding result. Different transmission powers are allocated for the ACK signal and the NACK signal. Alternatively, the transmission power for the NACK signal selectively has an OFF level. The present invention optimizes the transmission powers for downlink ACK/NACK signals in accordance with the required reception quality of each of the ACK/NACK signals, and thus, enables the system to operate efficiently.

Description

CONFIRMATION OF PACKAGE TRANSMISSION IN WIRELESS COMMUNICATION SYSTEM Technical Field The present invention relates to a method for transmitting a negative confirmation / confirmation signal (ACK / NACK), and more particularly, to transmit an ACK / NACK signal from a network which receives packet data transmitted from a user equipment (ÜE) through an uplink data channel.

Background Technique The Third Generation Society Project (3GPP) is discussing the application of the Hybrid Automatic Repetition Request (HARQ) scheme to a channel for the high-speed transmission of uplink packet data. Such a channel is known as an enhanced dedicated uplink (E-DCH) channel. In an application of the HARQ system to the uplink, a network transmits (eg, node-B), in response to a packet sent from a user equipment (ÜE), a negative confirmation signal (NACK) to the ÜE when it is determines, based on the results obtained after decoding the packet, that the packet is decoded erroneously, and transmits a confirmation signal (ACK) to the UE when it is determined that the packet is decoded successfully. The ACK / NACK signal is transmitted through a 1-bit ACK / NACK channel. In response to receiving the NACK signal, the UE retransmits the previously transmitted packet. The node B combines the decoding information on the retransmitted packet with the decoding information on the previously transmitted packet, using various transmission methods to improve the reception performance for the retransmitted packet. In this case, the ACK / NACK signal is a 1 bit signal which is transmitted in the downlink. For such an ACK / NACK signal, no channel coding is provided to protect it from interference or other adverse communication conditions. For this reason, it is necessary to use very high transmit power to allow the UE to successfully receive the ACK / NACK signal. In the HARQ system, the NACK signal must have a transmission success rate higher than that of the ACK signal. When the UE erroneously receives an ACK signal as a NACK signal, the UR transmits the packet, which was already received by the node B. Therefore, no other damage occurs than retransmitting the same data. However, when the UE erroneously receives a NACK signal as an ACK signal, the UE erroneously determines that the associated packet data was successfully transmitted to the node B, and then transmits a subsequent packet. As a result, the erroneously decoded packet can no longer be recovered in the physical layers of node B. The recovery of the erroneous packet must be carried out in a higher layer. As a result, the packet transmission delay increases. Further, when the UE is in rapid transit, or a temporary transfer with a plurality of nodes B, the state of the link between the UE and each node B may be very weak. In this case, the ACK / NACK transmit power (in particular, the NACK transmit power) required to obtain a satisfactory ACK / NACK reception performance may be impractically high. Therefore, it is necessary to properly set the downlink ACK / NACK transmit power, taking into account all the aforementioned possibilities. Therefore, a need remains for an improved means for ACK / NACK communication in a wireless system using the dedicated dedicated uplink channel that solves these and related problems.

Description of the Invention Accordingly, the present invention is directed to methods for transmitting an ACK / NACK signal and determining the ACK / NACK in the uplink packet transmission which substantially make one or more problems obvious due to limitations and disadvantages of the related technique. An object of the present invention is to provide methods for transmitting an ACK / NACK signal and determining the ACK / NACK in the uplink packet transmission, which is able to achieve efficient transmission of the ACK / NACK signal, and a reliable determination of ACK / NACK. Advantages, objects, and additional features of the invention will be set forth in part of the description which follows and in part will become apparent to those who have ordinary experience in the art with the examination of the following or can be learned from the practice of the art. invention. The objects and other advantages of the invention can be realized and obtained by the structure particularly indicated in the written description and the claims thereof as well as the attached drawings. To achieve these objects and other advantages and in accordance with the purpose of the invention, as widely represented and described herein, a method for receiving confirmation of uplink data in a wireless communication system comprises transmitting packet data. from a user equipment to at least one of a service network and a non-service network through a dedicated channel; receiving a first confirmation status indicator of the service network in response to decoding the packet data by the service network, wherein the first confirmation status indicator is transmitted using a phase shift modulation; and receiving a second confirmation status indicator from the serviceless network in response to decoding the packet data through the serviceless network, where the second confirmation status indicator is transmitted using an amplitude shift modulation. Preferably, the dedicated channel is a dedicated dedicated uplink channel. According to one aspect of the invention, the first confirmation status indicator comprises a confirmation indicator if the packet data is decoded without error and a negative confirmation indicator if the packet data is decoded in error. The second confirmation status indicator comprises a confirmation indicator if the packet data is decoded without error and no signal is received if the packet data is decoded in error. Preferably, the confirmation indicator comprises a signal of positive amplitude. According to another aspect of the invention, the phase shift modulation comprises a binary phase shift modulation. In addition, the modulation by phase shift by amplitude comprises an on-off modulation. According to another aspect of the invention, the user equipment is in communication with the network without service during a temporary transfer. According to another embodiment of the invention, a method of receiving confirmation of uplink data over a network comprises receiving packet data from a user equipment through a dedicated channel; decode packet data; transmitting a first confirmation status indicator in response to decoding the packet data, wherein the first confirmation status indicator is transmitted using a phase shift modulation if the network is a service network of the user equipment; and transmitting a second confirmation status indicator in response to decoding the packet data, wherein the second confirmation status indicator is transmitted using an amplitude shift modulation if the network is a non-service network of the user equipment. According to another embodiment, a mobile terminal for communicating uplink data in a wireless communication system comprises means for transmitting packet data to at least one of a service network and a non-serving network through a dedicated channel; means for receiving a first confirmation status indicator from the service network in response to decoding the packet data by the service network, wherein the first confirmation status indicator is transmitted using a phase shift modulation; and means for receiving a second confirmation status indicator from the serviceless network in response to decoding the packet data through the serviceless network, wherein the second confirmation status indicator is transmitted using an amplitude shift modulation. According to another embodiment, a network such as node B, for receiving uplink data confirmation comprises means for receiving packet data from a user equipment through a dedicated channel; means for decoding packet data; means for transmitting a first confirmation status indicator in response to decoding the packet data, wherein the first confirmation status indicator is transmitted using a phase shift modulation if the network is a service network of the user equipment; and means for transmitting a second confirmation status indicator in response to decoding the packet data, wherein the second confirmation status indicator is transmitted using an amplitude shift modulation if the network is a non-service network of the user equipment. It will be understood that both the above generated description and the following detailed description of the present invention are exemplary and explanatory if it is intended to provide a further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated into and constitute a part of this application, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention. invention. In the drawings: FIGURE 1 is a diagram explaining a method of assigning ACK / NACK signal transmission power according to a first embodiment of the present invention. FIGURE 2 is a diagram explaining a method of assigning ACK / NACK signal transmission power according to a second embodiment of the present invention. FIGURE 3 illustrates a wireless communication system that implements the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Reference will now be made in detail to the preferred embodiments of the present invention, of which examples are illustrated in the accompanying drawings. Whenever possible, the same reference numbers will be used throughout the drawings to refer to the same or similar parts. According to the recent demand for improved uplinks in wireless mobile communication system, a system for transmitting high-speed packets in an uplink transmission from a mobile terminal (also known as user equipment) to a node B is needed. An enhanced dedicated uplink (E-DCH) channel has been created with that purpose in mind. A user equipment (ÜE) transmits a packet to a node B at high speed by means of E-DCH. The node B decodes the received packet, and determines success or failure of the packet reception based on the decoding result. Based on the result of the determination, node B transmits a physical layer confirmation / confirmation (ACK / NACK) signal. In this way, a fast automatic replay request (ARQ) operation is carried out. In some systems, the required qualities of reception of the ACK and NACK signals may be different from each other. Therefore, when the ACK and NACK signals are transmitted via an ACK / NACK channel, it may be necessary to set the transmit power for the ACK signal and the transmit power for the NACK signal at different levels. In some cases, it can be efficient to detect only ACK signals using a threshold. In such a case, the transmission power for the NACK signals has a level of OFF (discontinuous transmissions (DTX)). In other words, no NACK signal is transmitted. Therefore, according to the present invention, the parameters of the ACK / NACK signal transmission power are defined in order to allow the adjustment of the different transmission power levels for the ACK and NACK signals transmitted from a node. B, and to allow discontinuous transmissions of NACK signals. This is also known as an on-off or amplitude shift modulation. Alternatively, the transmission power levels of the ACK and NACK signals may be different from each other. Generally, more serious problems can occur when there is an error in the NACK signal, when there is an error in the ACK signal. For this reason, the highest transmit power is required to transmit the NACK signal. If the ACK and NACK signals are transmitted using the same transmission power, the transmission of the NACK signal is carried out at an insufficient transmission power level, and the transmission of the ACK signal is carried out at a excessive transmission power level. This can cause problems. Accordingly, if the transmission power levels for the transmission of the ACK signal and the transmission of the NACK signal are set to be different from one another, it is possible to more efficiently achieve the transmission of the ACK and NACK signals. FIGURE 1 is a diagram of an ACK / NACK signal transmission power allocation method according to the first embodiment of the present invention. With reference to FIGURE 1, different levels of transmit power are used for the ACK and NACK signals, respectively, to allow the ACK and NACK signals to be transmitted in a binary phase shift (BPSK) form. Preferably, the modulation of BPSK to transmit the ACK / NACK signal is used for a case without transfer (for example, the UE is in communication with only a serving node B). For the purpose of explaining the present invention, node B can also be referred to as a network. Preferably, the UE can determine the reception of an ACK signal with the signal transmitted via a downlink ACK / NACK channel and received by the UE having a positive voltage level (+), and the reception of a signal of NACK when the received signal has a negative voltage level (-), as shown in Figure 1. According to the first embodiment of the present invention, the transmit power of the dedicated downlink channels for the UEs can be set , using offset values for the transmit power of dedicated physical downlink data channels (the DPDCHs). Accordingly, the transmit powers for the ACK / NACK signals transmitted in a downlink can be established, using the offset values for the transmit power of the downlink DPDCHs. The transmit powers of the ACK and NACK signals can be preferably set at different levels (eg, shifted by phase) by determining the parameters of the transmit power levels for the ACK and NACK signals between a network controller of radio (RNC) and a node B respectively. For example, when it is assumed that the "P0ACK" parameter represents a power offset for a downlink DPDCH in the transmission of an ACK signal, and the "POKACK" parameter represents a power offset for the downlink DPDCH in When transmitting a NACK signal, it is possible to control the transmission powers for the ACK and NACK signals in such a way that they have different levels when sending the parameters of the RNC to the node B. For example, when DTX of the NACK signal is refers, this is achieved by setting the "PONACK" parameter to "0" ("PONACK" = 0). It is preferred that the parameters are also sent to the UEs to allow each UE to select a desired one of a BPSK detection and a threshold detection for the ACK and NACK signals received by the UE, and to select an appropriate threshold value in the case of threshold detection. For a UE that is in transfer, preferably temporary transfer, it may be possible to always control the transmit power for the NACK signal to have a DTX level. That is, for the UE that is in transfer, the allocation of the downlink ACK / NACK transmit power can be achieved in such a way that the transmit power for the ACK signal is set to be higher than a value of default threshold, using the "PONACK" parameter * that is, the power offset for the downlink DPDCH in the transmission of the ACK signal, and the transmit power for the NACK signal is set to be 0"(OFF) It is preferred that the "PONACK" parameter is also sent to the UE, in order to allow the UE to select an appropriate threshold value for the reception of the ACK / NACK signals, FIGURE 2 is a diagram of an assignment method. ACK / NACK signal transmission power according to another embodiment of the present invention When the ACK / NACK downlink channel, through which the node B transmits an ACK / NACK signal, is in a degraded state, the transmission power for the ACK / NACK signal may be insufficient. Therefore, it is necessary to preferentially ensure the success of the NACK signal transmission, about the success of the ACK signal transmission. In order to be able to preferentially ensure the success of the NACK signal transmission, the allocation of the signal transmission power can be carried out according to the method illustrated in FIGURE 2. That is, only the ACK signal can be transmitted using transmission power of a predetermined level under the condition in which the transmission power for the NACK signal has a level OFF (DTX). The transmission of the ACK signal using a predetermined amplitude and the discontinuous transmission of the NACK signal are known as amplitude shift modulation. Preferably, the UE can detect the ACK signal using a threshold. That is, the UE determines the reception of an ACK signal when the signal transmitted by a downlink ACK / NACK channel and received by the UE has a voltage level higher than a predetermined threshold value, and the reception of a NACK signal when the received signal has a voltage level no higher than the predetermined threshold value. Where the threshold value for the detection of ACK / NACK is set to be high enough on the UE side, it is possible to ensure a desired probability of successful transmission of the NACK signals even though the transmission power for the ACK signal is insufficient. A method for efficiently establishing the transmission powers for the ACK / NACK signals according to the second embodiment of the present invention will be described. According to the second embodiment, the displacement modulation by amplitude is applied, preferably during a case of temporary transfer. In other words, the UE is in communication with a service cell as well as at least one cell without service. In the second mode, the RNC informs the node B of whether the transmission power for the NACK signal should or should not have a level of OFF (DTX), taking into consideration whether the associated UE is or is not in temporary transfer, and other conditions associated with the transmission of the ACK and NACK signals. For example, the physical layers of node B can transmit a NACK signal, using the NACK signal transmission power set to "O" (for example, using a signal called "NACK_PW_OFF") when a parameter received from a higher layer has a value of 1, and using the signal transmission power of NACK determined by the RNC when the received parameter has a value of 0. The information on the transmission power levels for the ACK / NACK signals is preferably sent from the RNC to node B. When the transmission power of the NACK signal has a different level than 0"in the example described above, a simple parameter for the transmission power level determined by the RNC can be used to set the transmit powers for the ACK and NACK signals in such a way that they have the same level, for an easy implementation of the transmission power adjustment described above. parameter can be ?? POACK / NACK "which is a displacement value for the transmission power of the downlink DPDCH for the transmission of the ACK / NACK signals, preferably the parameter" PO¾CK / NACK "must also be sent to the UE in order to allow that the UE selects an appropriate threshold value for the reception of the ACK / NACK signals. The transmission powers for the ACK and NACK signals can be independently established using two independent parameters, respectively, to allow node B to use the power more efficiently. The transmit power for the ACK signal is preferably set using the power offset for the downlink DPDCH in the ACK signal transmission, particularly, "POACK" / - while the transmit power for the NACK signal may be set using the power offset for the downlink DPDCH in the NACK signal transmission, for example, "PONACK" - In this case, the value ?????? "must also be sent to the UE to allow the UE select an appropriate threshold value for the reception of the ACK / NACK signals, FIGURE 3 illustrates a wireless communication system implementing the present invention, as shown, a mobile terminal, or a user equipment 2 (UE). connects to a central network 4 (CN) through a UMTS terrestrial radio access network 6 (UTRAN) UTRAN 6, configures, maintains and manages a radio access bearer for communication between the UE 2 and the network cen The UTRAN 6 includes a plurality of radio network subsystems 8 (RNS), each of which comprises a radio network controller (RNC) 10 for a plurality of base stations, or nodes B 12. The RNC 10 connected to a given base station 12 is the control RNC for assigning and handling the common resources provided by any number of UE 2 operating in a cell. One or more cells exist in a node B. The control RNC 10 controls the traffic load, the congestion of cells, and the acceptance of new radio links. Each node B 12 can receive an uplink signal from a UE 2 and can transmit downlink signals to the UE 2. Each node B 12 serves as an access point that allows a UE 2 to connect to the UTRAN 6, while a RNC 10 serves as an access point to connect the nodes B corresponding to the central network 4. As apparent from the above description, the present invention can optimize the transmit powers for the downlink ACK / NACK signals according to the required reception quality of each of the ACK / NACK signals, and this mode, allows the system to operate efficiently. It will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention with the proviso that they fall within the scope of the appended claims and their equivalents.

Industrial Applicability The present invention can be applied to a broadband wireless access system.

Claims (18)

1. CLAIMS 1. A method of receiving confirmation of uplink data in a wireless communication system, the method comprising: transmitting packet data from a user equipment to at least one of a service network and a network without service to through a dedicated channel; receiving a first confirmation status indicator from the service network in response to decoding the packet data by the service network, wherein the first confirmation status indicator is transmitted using a phase shift modulation; and receiving a second confirmation status indicator from the non-serving network in response to decoding the packet data over the non-serving network, wherein the second confirmation status indicator is transmitted using an amplitude shift modulation. The method of claim 1, wherein the first confirmation status indicator comprises a confirmation indicator if the packet data is decoded without error and a negative confirmation indicator if the packet data is decoded in error. The method of claim 1, wherein the second confirmation status indicator comprises a confirmation indicator if the packet data is decoded without error and no signal is received if the packet data is decoded in error. 4. The method of claim 3, wherein the confirmation indicator comprises a signal of positive amplitude. The method of claim 1, wherein the phase shift modulation comprises a binary phase shift modulation. The method of claim 1, wherein the amplitude shift modulation comprises an on-off modulation. The method of claim 1, wherein the dedicated channel is an enhanced dedicated uplink channel. The method of claim 1, wherein the user equipment is in communication with the network without service during a temporary transfer. 9. A method of receiving confirmation of uplink data over a network in a wireless communication system, the method comprising: receiving packet data from a user equipment through a dedicated channel; decode packet data; transmitting a first confirmation status indicator in response to decoding the packet data, wherein the first confirmation status indicator is transmitted using a phase shift modulation if the network is a service network of the user equipment; and transmitting a second confirmation status indicator in response to decoding the packet data, wherein the second confirmation status indicator is transmitted using an amplitude shift modulation if the network is a non-service network of the user equipment. The method of claim 9, wherein the first confirmation status indicator comprises a confirmation indicator if the packet data is decoded without error and a negative confirmation indicator if the packet data is decoded in error. The method of claim 9, wherein the second confirmation status indicator comprises a confirmation indicator if the packet data is decoded without error and no signal is received if the packet data is decoded in error. The method of claim 11, wherein the confirmation indicator comprises a signal of positive amplitude. The method of claim 9, wherein the phase shift modulation comprises a binary phase shift modulation. The method of claim 9, wherein the amplitude shift modulation comprises an on-off modulation. 15. The method of claim 9, wherein the dedicated channel is a dedicated uplink dedicated channel. 16. The method of claim 9, wherein the user equipment is in communication with the network without service during a temporary transfer. 17. A mobile terminal for communicating uplink data in a wireless communication system, the mobile terminal comprising: means for transmitting packet data to at least one of a service network and a non-service network through a dedicated channel; means for receiving a first confirmation status indicator of the service network in response to decoding the packet data by the service network, wherein the first confirmation status indicator is transmitted using a phase shift modulation; and means for receiving a second confirmation status indicator from the serviceless network in response to decoding the packet data through the serviceless network, wherein the second confirmation status indicator is transmitted using an amplitude shift modulation. 18. A network for receiving uplink data confirmation in a wireless communication system, the network comprising: means for receiving packet data from a user equipment through a dedicated channel; means for decoding packet data; means for transmitting a first confirmation status indicator in response to decoding the packet data, wherein the first confirmation status indicator is transmitted using phase shift modulation if the network is a service network of the user equipment; and means for transmitting a second confirmation status indicator in response to decoding the packet data, wherein the second confirmation status indicator is transmitted using an amplitude shift modulation if the network is a non-service network of the user equipment. .