TW201505402A - Combination of multiple precoding techniques for multicarrier modulation systems - Google Patents

Abstract

Systems, methods, and instrumentalities are disclosed to utilize a combined precoding technique in a multicarrier modulation system to reduce out-of-band power leakage. A combined precoder may be used to precode a symbol stream using a matrix-based precoding component to generate a first precoded symbol stream. The combined precoder may then be used to apply a perturbation to the first precoded symbol stream to generate a second precoded symbol stream.

Description

Multi-carrier modulation system multi-precoding technology combination

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the disclosure.

Multi-Carrier Modulation (MCM) technology can transmit a set of data on multiple narrow-band subcarriers simultaneously. By using advanced wideband modulation and coding schemes, systems using MCM can achieve higher spectral efficiency in frequency selective channels than systems using single carrier modulation techniques. An orthogonal frequency division multiplexing (OFDM) technique that divides the total frequency band into a plurality of orthogonal sub-bands that overlap in frequency is an example of an MCM scheme. OFDM can have several advantageous features such as high spectral efficiency, robustness to channel fading, multipath delay spread tolerance, efficient fast Fourier transform (FFT) implementation, and the like. However, one problem is the high sidelobe of its subcarriers. Thus, OFDM signals can produce relatively large out-of-band (OOB) radiation and/or out-of-band emissions (OOBE) and can be undesirable for certain wireless communication systems and applications. For example, cognitive radio (CR) has recently received significant attention as a promising solution to the problem of spectrum congestion caused by rapidly increasing number of wireless communication technologies and devices. The CR system can operate in the frequency band allocated to the licensed user (LU) by utilizing the idle portion of the LU band and can reduce or minimize its interference to the LU. OFDM has been recognized as a CR candidate for use in the standard IEEE 802.22 based on the first cognitive radio. OFDM-based CR systems suffer from large OOB radiation that interferes with other frequency bands occupied by the LU.

Systems, methods, and tools are disclosed to use a combined precoding technique in a multi-carrier modulation system. A combined precoder may be used to precode the symbol stream by using a matrix based precoding element to produce a first precoded symbol stream. The combined precoder may then be used to perturb the first precoded symbol stream to produce a second precoded symbol stream. Thus, the OOBE associated with the transmission of the second precoded symbol stream may be less than the OOBE associated with the transmission of the unencoded data stream. For example, the matrix based precoding scheme may include one or more of a singular value decomposition (SVD) precoder scheme, an N-continuous precoder scheme, a spectral precoding scheme, and the like. A perturbation may be added to the first precoded symbol stream when the second precoded symbol stream is generated. The perturbation may be transmitted on the first set of subcarriers and the data symbol string may be transmitted on the second set of subcarriers. The first precoding scheme may reduce OOBE by utilizing the first precoding matrix attributes, and the second precoding scheme may reduce OOBE by utilizing other precoding matrix attributes. For example, the first precoding attribute may be a zero space attribute and the second precoding attribute may be a continuous derivative attribute.

The detailed description can now be described with reference to the drawings. While the description provides specific examples of possible implementations, it should be noted that the specific examples are illustrative and are not intended to limit the scope of the application. FIG. 1A is a system diagram of an example communication system 100 in which one or more embodiments may be implemented. Communication system 100 can be a multiple access system that provides content to multiple users, such as voice, data, video, messaging, broadcast, and the like. Communication system 100 can enable multiple wireless users to access such content through system resource sharing, including wireless bandwidth. For example, communication system 100 can use one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), Single carrier FMDA (SC-FDMA), etc. As shown in FIG. 1A, communication system 100 can include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, and/or 102d (which are generally or collectively referred to as WTRUs 102), Radio Access Network (RAN) 103. /104/105, core network 106/107/109, public switched telephone network (PSTN) 108, internet 110 and other networks 112. It should be understood, however, that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d may be configured to transmit and/or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, pagers, mobile phones, individuals Digital assistants (PDAs), smart phones, notebook computers, portable Internet devices, personal computers, wireless sensors, consumer electronics, and more. Communication system 100 can also include a base station 114a and a base station 114b. Each of the base stations 114a, 114b can be configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the core network 106/107/109, Any type of device of the Internet 110 and/or the network 112. By way of example, base stations 114a, 114b may be base station transceiver stations (BTS), node B, eNodeB, home node B, home eNodeB, website controller, access point (AP), wireless router, and the like. While each of the base stations 114a, 114b is depicted as a separate component, it should be understood that the base stations 114a, 114b can include any number of interconnected base stations and/or network elements. The base station 114a may be part of the RAN 103/104105, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC). , relay nodes, etc. Base station 114a and/or base station 114b may be configured to transmit and/or receive wireless signals within a particular geographic area, which may be referred to as a cell (not shown). Cells can also be divided into cell sectors. For example, a cell associated with base station 114a can be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one for each sector of a cell. In another embodiment, base station 114a may use multiple input multiple output (MIMO) technology, so multiple transceivers may be used for each sector of the cell. The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over the null plane 115/116/117, which may be any suitable wireless communication link (eg, radio frequency (RF)) , microwave, infrared (IR), ultraviolet (UV), visible light, etc.). The null interfacing surface 115/116/117 can be established using any suitable radio access technology (RAT). More specifically, as noted above, communication system 100 can be a multiple access system and can employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, base station 114a and WTRUs 102a, 102b, 102c in RAN 103/104/105 may use a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) Establish an empty intermediary plane 115/116/117. WCDMA may include communication protocols such as High Speed Packet Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High Speed Downlink Packet Access (HSDPA) and/or High Speed Uplink Packet Access (HSUPA). In another embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may use a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may use Long Term Evolution (LTE) and/or LTE-Advanced ( LTE-A) to establish an empty intermediate plane 115/116/117. In other embodiments, base station 114a and WTRUs 102a, 102b, 102c may use, for example, IEEE 802.16 (ie, Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS) -2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rate for GSM Evolution (EDGE), GSM EDGE (GERAN), etc. technology. The base station 114b in FIG. 1A may be a wireless router, a home Node B, a home eNodeB, or an access point, for example, and any suitable RAT may be used to facilitate wireless connectivity in a local area, such as a commercial location, a residence, Vehicles, campuses, etc. In one embodiment, base station 114b and WTRUs 102c, 102d may exemplify a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, base station 114b and WTRUs 102c, 102d may establish a wireless personal area network (WPAN) using a radio technology such as IEEE 802.15. In still another embodiment, base station 114b and WTRUs 102c, 102d may use a cellular based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.) to establish picocells or femtocells. As shown in FIG. 1A, the base station 114b can have a direct connection to the Internet 110. Thus, base station 114b may not need to access Internet 110 via core network 106/107/109. The RAN 103/104/105 may be in communication with a core network 106/107/109, which may be configured to provide voice to one or more of the WTRUs 102a, 102b, 102c, 102d, Any type of network such as data, applications, and/or Voice over Internet Protocol (VoIP) services. For example, the core network 106/107/109 may provide call control, billing services, mobile location based services, prepaid calling, internet connectivity, video distribution, etc. and/or perform advanced security functions such as user authentication. Although not shown in FIG. 1A, it should be understood that the RAN 103/104/105 and/or the core network 106/107/109 may be associated with the same RAT as the RAN 103/104/105 or other RANs of different RATs. Direct or indirect communication. For example, in addition to being connected to the RAN 103/104/105 that is using the E-UTRA radio technology, the core network 106/107/109 can also communicate with another RAN (not shown) that uses the GSM radio technology. The core network 106/107/109 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and/or other networks 112. The PSTN 108 may include a circuit switched telephone network that provides Plain Old Telephone Service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use public communication protocols, such as Transmission Control Protocol (TCP) in the TCP/IP Internet Protocol Group, User Data Packet Protocol (UDP). ) and Internet Protocol (IP). Network 112 may include a wired or wireless communication network that is owned and/or operated by other service providers. For example, the network 112 may include another core network connected to one or more RANs that may use the same RAT as the RAN 103/104/105 or a different RAT. Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities, for example, the WTRUs 102a, 102b, 102c, 102d may include communications for communicating with different wireless networks over different wireless links. Multiple transceivers. For example, the WTRU 102c shown in FIG. 1A can be configured to communicate with a base station 114a that can communicate with the base station 114b using a cellular-based radio technology, and the base station 114b can use IEEE 802 radio technology. . FIG. 1B is a system diagram of an example of a WTRU 102. As shown in FIG. 1B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a numeric keypad 126, a display/touchpad 128, a non-removable memory 130, and a removable In addition to memory 132, power source 134, global positioning system (GPS) chipset 136, and other peripheral devices 138. It should be understood that the WTRU 102 may include any sub-combination of the aforementioned elements while remaining consistent with the embodiments. Moreover, embodiments take into account base stations 114a and 114b, and/or nodes that base stations 114a and 114b can represent, such as, but not limited to, base station transceiver stations (BTS), node B, website controllers, access points (APs). , Home Node B, Evolved Home Node B (eNode B), Home Evolved Node B (HeNB), Home Evolved Node B Gateway, Proxy Node, etc., may include the description described in FIG. 1B and described herein. Some or all of the components. The processor 118 can be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with the DSP core, a controller, a micro control , dedicated integrated circuit (ASIC), field programmable gate array (FPGA) circuits, any other type of integrated circuit (IC), state machine, and more. The processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other function that causes the WTRU 102 to operate in a wireless environment. The processor 118 can be coupled to a transceiver 120 that can be coupled to the transmit/receive element 122. Although FIG. 1B depicts processor 118 and transceiver 120 as separate components, it should be understood that processor 118 and transceiver 120 can be integrated together in an electronic package or wafer. The transmit/receive element 122 can be configured to transmit signals to or from a base station (e.g., base station 114a) via the null planes 115/116/117. For example, in one embodiment, the transmit/receive element 122 can be an antenna configured to transmit and/or receive RF signals. In another embodiment, the transmit/receive element 122 can be a transmitter/detector configured to transmit and/or receive, for example, IR, UV, or visible light signals. In still another embodiment, the transmit/receive element 122 can be configured to transmit and receive both RF and optical signals. It should be understood that the transmit/receive element 122 can be configured to transmit and/or receive any combination of wireless signals. Additionally, although the transmit/receive element 122 is depicted as a separate element in FIG. 1B, the WTRU 102 may include any number of transmit/receive elements 122. More specifically, the WTRU 102 may use, for example, MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the null intermediaries 115/116/117. The transceiver 120 can be configured to modulate signals to be transmitted by the transmit/receive element 122 and/or demodulate signals received by the transmit/receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Transceiver 120 may thus include a plurality of transceivers that cause WTRU 102 to communicate via a plurality of RATs, such as UTRA and IEEE 802.11. The processor 118 of the WTRU 102 may be coupled to a device and may receive user input data from a speaker/microphone 124, a numeric keypad 126, and/or a display/touchpad 128 (eg, a liquid crystal display (LCD) a display unit or an organic light emitting diode (OLED) display unit). The processor 118 can also output user data to the speaker/microphone 124, keyboard number 126, and/or display/trackpad 128. Additionally, processor 118 can access information from any type of suitable memory and can store the data into any type of suitable memory, such as non-removable memory 130 and/or removable memory 132. Non-removable memory 130 may include random access memory (RAM), read only memory (ROM), hard disk, or any other type of memory device. The removable memory 132 can include a Subscriber Identity Module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from memory that is not located on the WTRU 102 at a physical location, such as on a server or a home computer (not shown), and may store data in the memory. in. The processor 118 can receive power from the power source 134 and can be configured to allocate and/or control power to other components in the WTRU 102. Power source 134 can be any suitable device that powers WTRU 102. For example, the power source 134 may include one or more dry cells (eg, nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), solar cells, fuel cells, etc. . The processor 118 may also be coupled to a GPS chipset 136 that may be configured to provide location information (eg, longitude and latitude) regarding the current location of the WTRU 102. The WTRU 102 may receive location information from or to the base station (e.g., base station 114a, 114b) plus or in place of the GPS chipset 136 information via the nulling plane 115/116/117 and/or based on two or more neighboring base stations. The timing of the received signal determines its position. It should be understood that the WTRU 102 may obtain location information by any suitable location determination method while maintaining consistency of implementation. The processor 118 can also be coupled to other peripheral devices 138, which can include one or more software and/or hardware modules that provide additional features, functionality, and/or wired or wireless connections. For example, peripheral device 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photo or video), a universal serial bus (USB) port, a vibrating device, a television transceiver, hands-free headset, Bluetooth ( Bluetooth^® Modules, FM radio units, digital music players, media players, video game console modules, Internet browsers, and more. 1C is a system diagram of RAN 103 and core network 106, in accordance with an embodiment. As mentioned above, the RAN 103 can communicate with the WTRUs 102a, 102b, and 102c over the null plane 115 using UTRA radio technology. The RAN 103 can also communicate with the core network 106. As shown in FIG. 1C, RAN 103 may include Node Bs 140a, 140b, 140c, each of Node Bs 140a, 140b, 140c including one or more for communicating with WTRUs 102a, 102b, 102c, 102d over null plane 115 Transceiver. Each of Node Bs 140a, 140b, 140c can be associated with a particular cell (not shown) within RAN 103. The RAN 103 may also include RNCs 142a, 142b. It should be understood that the RAN 103 may include any number of Node Bs and RNCs while maintaining consistency of implementation. As shown in FIG. 1C, Node Bs 140a, 140b can communicate with RNC 142a. Additionally, Node B 140c can communicate with RNC 142b. Node Bs 140a, 140b, 140c can communicate with respective RNCs 142a, 142b via an Iub interface. The RNCs 142a, 142b can communicate with one another via the Iur interface. Each of the RNCs 142a, 142b can be configured to control the respective Node Bs 140a, 140b, 140c to which it is connected. Additionally, each of the RNCs 142a, 142b can be configured to perform or support other functions, such as outer loop power control, load control, admission control, packet scheduling, handover control, macro diversity, security functions, data encryption, and the like. . The core network 106 shown in FIG. 1C may include a media gateway (MGW) 144, a mobile switching center (MSC) 146, a Serving GPRS Support Node (SGSN) 148, and/or a Gateway GPRS Support Node (GGSN) 150. . While each of the foregoing elements is described as being part of core network 106, it should be understood that any of these elements may be owned or operated by an entity that is not a core network operator. The RNC 142a in the RAN 103 can be connected to the MSC 146 in the core network 106 via an IuCS interface. The MSC 146 can be connected to the MGW 144. The MSC 146 and the MGW 144 may provide the WTRUs 102a, 102b, 102c with access to a circuit-switched network (e.g., PSTN 108) to facilitate communications between the WTRUs 102a, 102b, 102c and conventional landline communication devices. The RNC 142a in the RAN 103 can also be connected to the SGSN 148 in the core network 106 via an IuPS interface. The SGSN 148 can be connected to the GGSN 150. The SGSN 148 and GGSN 150 may provide the WTRUs 102a, 102b, 102c with access to a packet switched network (e.g., the Internet 110) to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. As noted above, the core network 106 can also be connected to the network 112, which can include other wired or wireless networks owned or operated by other service providers. FIG. 1D is a system diagram of the RAN 104 and the core network 107 in accordance with an embodiment. As mentioned above, the RAN 104 can communicate with the WTRUs 102a, 102b, 102c over the null plane 116 using E-UTRA radio technology. The RAN 104 can also communicate with the core network 107. The RAN 104 may include eNodeBs 160a, 160b, 160c, although it will be appreciated that the RAN 104 may include any number of eNodeBs to maintain consistency with various embodiments. Each of the eNodeBs 160a, 160b, 160c may include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the null plane 116. In one embodiment, the eNodeBs 160a, 160b, 160c may use MIMO technology. Thus, eNodeB 160a, for example, may use multiple antennas to transmit and/or receive wireless signals to and from WTRU 102a. Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, subscriber ranks in the uplink and/or downlink Cheng and so on. As shown in FIG. 1D, the eNodeBs 160a, 160b, 160c can communicate with each other through the X2 interface. The core network 107 shown in FIG. 1D may include a Mobility Management Entity (MME) 162, a Serving Gateway 164, and a Packet Data Network (PDN) Gateway 166. While each of the foregoing elements is described as being part of core network 107, it should be understood that any of these elements may be owned and/or operated by entities other than the core network operator. The MME 162 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for user authentication of the WTRUs 102a, 102b, 102c, bearer initiation/deactivation, selection of a particular service gateway during initial attachment of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may also provide control plane functionality for switching between the RAN 104 and other RANs (not shown) using other radio technologies such as GSM or WCDMA. Service gateway 164 may be connected to each of eNBs 160a, 160b, 160c in RAN 104 via an S1 interface. The service gateway 164 can typically route and forward user data packets to/from the WTRUs 102a, 102b, 102c. The service gateway 164 may also perform other functions, such as anchoring the user plane during inter-eNB handovers, triggering paging, managing and storing the context of the WTRUs 102a, 102b, 102c when downlink information is available to the WTRUs 102a, 102b, 102c ( Context) and so on. The service gateway 164 may also be connected to a PDN gateway 166 that may provide the WTRUs 102a, 102b, 102c with access to a packet switched network (e.g., the Internet 110) to facilitate the WTRUs 102a, 102b, 102c. Communication with IP-enabled devices. The core network 107 can facilitate communication with other networks. For example, core network 107 may provide WTRUs 102a, 102b, 102c with access to a circuit-switched network (e.g., PSTN 108) to facilitate communications between WTRUs 102a, 102b, 102c and conventional landline communication devices. For example, core network 107 may include or be in communication with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between core network 107 and PSTN 108. In addition, core network 107 can provide WTRUs 102a, 102b, 102c with access to network 112, which can include other wired or wireless networks that are owned and/or operated by other service providers. FIG. 1E is a system diagram of the RAN 105 and the core network 109 in accordance with an embodiment. The RAN 105 may be an Access Service Network (ASN) that communicates with the WTRUs 102a, 102b, 102c over the null plane 117 using IEEE 802.16 radio technology. As discussed further below, the links between the different functional entities of the WTRUs 102a, 102b, 102c, RAN 105, and core network 109 may be defined as reference points. As shown in FIG. 1E, the RAN 105 can include base stations 180a, 180b, 180c and ASN gateway 182, although it should be understood that the RAN 105 can include any number of base stations and ASN gateways consistent with the embodiment. Each of the base stations 180a, 180b, 180c may be associated with a particular cell (not shown) in the RAN 105 and may include one or more transceivers that communicate with the WTRUs 102a, 102b, 102c over the null plane 117. In one example, base stations 180a, 180b, 180c may use MIMO technology. Thus, base station 180a, for example, may use multiple antennas to transmit wireless signals to, or receive wireless signals from, WTRU 102a. The base stations 180a, 180b, 180c may provide mobility management functions such as handoff triggering, tunnel establishment, radio resource management, traffic classification, quality of service (QoS) policy enforcement, and the like. The ASN gateway 182 can act as a service aggregation point and is responsible for paging, caching user profiles, routing to the core network 109, and the like. The null interfacing plane 117 between the WTRUs 102a, 102b, 102c and the RAN 105 may be defined as an Rl reference point implementing the 802.16 specification. In addition, each of the WTRUs 102a, 102b, 102c can establish a logical interface (not shown) with the core network 109. The logical interface between the WTRUs 102a, 102b, 102c and the core network 109 can be defined as an R2 reference point that can be used for authentication, authorization, IP host configuration management, and/or mobility management. The communication link between each of the base stations 180a, 180b, 180c may be defined as an R8 reference point that includes a protocol that facilitates WTRU handover and inter-base station transfer of data. The communication link between base stations 180a, 180b, 180c and ASN gateway 182 may be defined as an R6 reference point. The R6 reference point may include an agreement to facilitate mobility management based on mobility events associated with each of the WTRUs 102a, 102b, 102c. As shown in FIG. 1E, the RAN 105 can be connected to the core network 109. The communication link between the RAN 105 and the core network 109 can be defined as an R3 reference point that includes, for example, protocols that facilitate data transfer and mobility management capabilities. The core network 109 may include a Mobile IP Home Agent (MIP-HA) 184, an Authentication, Authorization, Accounting (AAA) server 186, and a gateway 188. While each of the foregoing elements is described as being part of core network 109, it should be understood that any of these elements may be owned or operated by an entity that is not a core network operator. The MIP-HA may be responsible for IP address management and may cause the WTRUs 102a, 102b, 102c to roam between different ASNs and/or different core networks. The MIP-HA 184 may provide the WTRUs 102a, 102b, 102c with access to a packet switched network (e.g., the Internet 110) to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The AAA server 186 can be responsible for user authentication and support for user services. Gateway 188 facilitates interworking with other networks. For example, gateway 188 can provide WTRUs 102a, 102b, 102c with access to a circuit-switched network (e.g., PSTN 108) to facilitate communications between WTRUs 102a, 102b, 102c and conventional landline communication devices. In addition, gateway 188 can provide access to network 112 to WTRUs 102a, 102b, 102c, which can include other wired or wireless networks owned or operated by other service providers. Although not shown in Figure 1E, it should be understood that the RAN 105 can be connected to other ASNs and the core network 109 can be connected to other core networks. The communication link between the RAN 105 and other ASNs may be defined as an R4 reference point, which may include an agreement to coordinate the mobility of the WTRUs 102a, 102b, 102c between the RAN 105 and other ASNs. The communication link between core network 109 and other core networks may be defined as an R5 reference point, which may include an agreement to facilitate interworking between the local core network and the visited core network. In a multi-carrier modulated transmitter, the combined precoding technique can achieve one or more multi-carrier modulated waveform design goals including reducing or minimizing out-of-band power leakage. For example, a combined precoding technique can combine multiple component precoding techniques in an ordered manner using matched coding rates to achieve one or more multi-carrier modulation design goals, such as reducing or minimizing out-of-band power leakage, reducing PAPR, reduce or minimize BER, etc. Each component precoding technique can be dedicated to one or more design goals and the combination of component precoders can be designed to implement components in sequence without defeating the popular functionality of the individual component precoding techniques. Examples of different precoding techniques that can be used as separate precoding elements of a combined precoding technique are described below. An exemplary combined precoder may use singular value decomposition (SVD) precoding as the first precoding element and spectral precoding as the second precoding element in the OFDM system to reduce or minimize OOB power leakage. In the transmitter, each composite symbol block can be processed twice before the IFFT operation. The first precoder may utilize an SVD precoder to notch or minimize out-of-band power emissions for power at specific frequencies located outside the passband. Next, a second component, which may be a spectral precoder, may be used to replace rectangular pulse shaping in OFDM with spectral precoding on subcarriers to achieve a faster drop in power spectral density outside the passband ( Roll off). At the receiver, after the FFT operation, the receiver can decode the block of signals in the reverse order of the transmit precoding process. Other types of component precoders can be used. For example, matrix based precoding techniques can be used in the first precoding element and can be combined with precoding techniques using perturbation vectors that can be implemented in the second precoding element. For example, SVD precoding may be implemented by a first precoding element, which may be combined with a second precoding element that implements an N continuous precoding technique to minimize OOB power leakage. For example, at the transmitter, SVD precoding can be applied to the data vector, and then the perturbation vector can be calculated and added to the precoded signal to perform equal to its previous symbol on the left edge of each CP-OFDM symbol. 1st to the right edgeJ Derivation. At the receiver, the perturbation vector can be estimated and subtracted from the received signal, and the data can be recovered by using the decoding matrix. The method of adding a perturbation vector can be implemented by extending the data vector to a space having a larger size and creating a perturbation vector orthogonal to the original data vector within the expanded space. In this manner, the operation of the receiver may not estimate the perturbation vector, but instead, the estimated data in the expanded space may be projected onto the original material. Some other types of transmission schemes may be used to reduce OOB radiation (other than or instead of using one or more precoding elements) of an orthogonal frequency division multiplexing (OFDM) based cognitive radio (CR) system. For example, filtering and/or windowing techniques can be used. However, for example, filtering and/or windowing techniques can introduce long delays and/or degradation of bit error rate (BER). Another exemplary method that can be used to reduce leakage involves prohibiting or avoiding the use of certain CR subcarriers to create one or more guard bands between the CR band and the LU band. However, purposefully creating a guard band only by avoiding the use of one or more subcarriers is not sufficient to reduce interference to a practically acceptable level, and this technique can result in some spectral efficiency loss. In one example, the cancel subcarrier (CC) can be used to generate an effective guard band and reduce spurious emissions. For example, instead of using or avoiding the use of subcarriers, the input to the designated CC may cause the radiation at a certain frequency that is typically assigned to the LU to be reduced or minimized. The content of the input to the CC may depend on the input of the remaining data subcarriers, which can be computationally complex, making it difficult to implement the use of the CC in practice. In one example, another method called subcarrier weight (SW) can be used as the precoding element. SW can be viewed as a precoding method using a real diagonal matrix that does not degrade spectral efficiency. Subcarrier weights may relate to the configuration of subcarrier inputs to reduce or minimize radiation at a certain frequency, and may also be computationally complex. Another exemplary precoding method that can be used as a precoding element is singular value decomposition (SVD) precoding. For example, although SVD precoding can reduce spectral efficiency to some extent, SVD can utilize a precoding matrix having a code rate of less than one to reduce OOB radiation. Unlike subcarrier weights, the matrices used in such precoding methods may not be square matrices. However, the design of the matrix does not depend on the input data. Therefore, the complexity of implementing such a precoder can be reduced compared to techniques that require knowledge of each input. Another precoding element scheme, such as spectral precoding, is also independent of the input data. Instead of reducing or minimizing SVD precoding of system energy at a certain frequency, spectral precoding uses a new set of orthogonal bases to replace rectangular pulses for each conventional OFDM symbol, so that the new side lobes fall more than the sinc function. fast. Spectral efficiency can be reduced by the number of available base sets that are limited when the in-band range is fixed. When the spectral efficiency decreases from 1 to (N-1)/N and from (N-1)/N to (N-2)/N, significant OOB power suppression improvement occurs, where N can be subcarrier Quantity. As spectral efficiency continues to decrease, improvements will become less significant. Thus, if a portion of the total spectral efficiency loss is reallocated from spectral precoding to some other precoding scheme, such as SVD precoding, the resulting combined scheme may be superior to any of the separately used schemes. Another example precoding element scheme may refer to N continuous precoding. N consecutive precoding can have near OOBE suppression effects, regardless of whether a cyclic prefix (CP) is used. For example, instead of designing a precoding matrix, N consecutive precoding can design a perturbation vector based on the current and previous symbols such that the corresponding time domain symbols can have continuous values and derivatives everywhere. Since the perturbation vector is not correctly estimated in the receiver when the maximum derivative order is large, some errors occur even when the channel is ideal and the iterative decoder is used. Greater OOBE suppression can be achieved by increasing the maximum derivative order. Orthogonal Frequency Division Multiplexing (OFDM) can have a peak-to-average power ratio (PAPR) that results in low power efficiency of the system. Many MCM systems experience high PAPR problems. The PAPR can be reduced by using signal scrambling techniques such as Select Level Mapping (SLM) and Partial Transfer Sequence (PTS) that would use perturbation coding to reduce PAPR. Typically side information is used in signal scrambling techniques where the signal scrambling technique introduces redundancy and the effective throughput is reduced. Precoding techniques can also be an effective way to reduce PAPR while introducing some redundancy while maintaining suitable error characteristics. PAPR can be reduced by signal distortion, which can reduce high peaks by direct distortion signals (eg, using compression techniques and clipping and filtering techniques). While this technique effectively reduces PAPR, it can significantly reduce error performance. Precoding techniques can provide remedies for the shortcomings of MCM systems such as OFDM systems. Different precoding techniques will achieve different goals in MCM waveform design. Integrating different aspects of different types of precoding techniques will achieve different design goals in the MCM waveform system while avoiding the undesirable effects of the individual techniques. For example, the precoding system can be designed to reduce or minimize OOB power leakage, reduce PARA, minimize BER, and the like. As shown in Figure 2, the combined precoding technique can be used to combine multiple separate precoding techniques, such as(1) Among them,G _N Can be the firstN Component precoder (for example, the data stream basically passes the firsti Precoders and can represent a precoding matrix of a precoding technique. FIG. 2 conceptually illustrates each of the component precoders of the combined precoder 200 as the precoder block 202. The use of a multi-element precoder may refer herein to the use of combined precoding. Combined precoding techniques can use a range of component precoders to meet multiple design goals. For example, each individual component precoder can be designed to address one or more design goals, such as reducing or minimizing OOB power leakage, reducing or minimizing PAPR, reducing or minimizing BER, and the like. In one example, the dimensionN _i ×K _i Firsti Precoding matrixG _i Can satisfy the matching coding rate (dimension) constraints, thusK _i =N _i -1 (2) Furthermore, the combination of precoding techniques can be designed such that the total combination of precoders does not disable one or more component precoding techniques (ie, ensuring that each precoder in the application combination does not overly Weaken the effect that individual precoders are designed to achieve). Figure 3 illustrates a transmitter 300 of an exemplary orthogonal frequency division multiplexing (OFDM) system. Figure 4 shows a receiver 400 of an OFDM system. Figures 3 and 4 can be used to illustrate the general case of a precoding OFDM (P-OFDM) system with any continuous or discontinuous available spectrum. To reduce out-of-band (OOB) power leakage when the available spectrum is discontinuous, an element precoding matrix can be designed to trap out-of-band frequencies. In one example, in addition to using multiple component precoders to process signals prior to transmission (eg, for various design purposes), a perturbation vector can be added for transmitting signals. For example, Figure 15 illustrates an example in which the combined precoder 1500 can be used with the perturbation vector. For example, order d _l =[d _1,l d _2,l ...d _k,l ] ^T Representativel Data vector, wherel Can be an index in the time domain andK Can be the length of each vector. Each vector can beN×K Precoding matrixG Multiply left and perturb the vector w _l =[w _1,l w _2,l ...w _N,l ] ^T For example, the resulting signal can be:b _l =Gd _l + w _l (3) whereb _l =[b _1,l b _2,l ...b _N,l ] ^T Can represent the firstl Precoding vectors. The coding rate can be defined as not more than one.K/N . x _l Can be corresponding to the inputb _l The inverse fast Fourier transform (IFFT) operation output. allowablex _l Insert the CP before, for example, to counteract the channel effect. At the receiver, the CP can receive the vector fromr ’ _l Was removed. Next, the received vector can be processed using a Fast Fourier Transform (FFT) block and by after the perturbation vector is estimated and removedK×N The decoding matrix is left-multiplied and decoded, for example, _l =( _l - _l ) (4) where _l Can be the estimated disturbance vector and _l It can be an estimated data signal. If the channel is ideal, then if _l =w _l andG=I The time data can be decoded correctly. In this combined precoding technique,G It can be defined similarly to that described in equation (1). As an example of a combined precoding technique, an element precoder can be used to reduce OOB power leakage in an OFDM system. For example, an exemplary SVD precoding method can be used as the first component precoder to power notch a certain frequency outside the passband (eg, to reduce out-of-band power transmission). The spectral precoding method can be designed to use spectral precoding on subcarriers instead of rectangular pulse shaping in OFDM to achieve a faster drop in spectral density power outside the passband and can be used as another component precoding Device. As generally shown in Figure 2 and/or Figure 15, these precoding methods can be used as component precoders in a combined precoder. By appropriately adjusting the dimensions of the precoding matrix (e.g., by appropriately assigning a matched code rate), the combined precoder may have a better OOB power suppression effect than any of the two individual component precoders. Figure 5 illustrates an exemplary OFDM system 500 that may employ precoding techniques. As shown in FIG. 5, the source bit stream can be mapped to the symbol stream by the PSK/QAM modulation block 502. The symbol stream can be applied to the serial to parallel (S/P) conversion block 504. in case d _l =[d _1,l d _2,l ...d _k,l ] ^T Representativel Data vector, wherel Can be an index in the time domain andK Can be the length of each vector, then the vector can beN×K Precoding matrixG Come left to multiply, thus:b _l =Gd _l (5) whereb _l =[b _1,l b _2,l ...b _N,l ] ^T May represent the first in precoding block 506l Precoding vectors. The coding rate can be defined as not more than one.K/N .x _l Can be in the IFFT block 508b _l Output. Cyclic prefix (CP) and/or zero padding (ZP) may be added to block 510. _l To offset the channel effect. The symbol stream can be transmitted through the channel at block 512. At the receiver, the CP and/or ZP may receive the vector from block 514.r' _l Was removed. The symbol stream can be processed by FFT block 516 and can be passed toK ×N The decoding matrix is left-multiplied and decoded, thereby: _l = _l (6) If the channel is ideal, thenG=I (7) The data can be decoded correctly. The decoded symbol stream can be processed in parallel to serial (P/S) conversion block 520 and can be mapped to a bit stream by PSK/QAM demodulation block 522. In SVD precoding, for a givenb _l Continuous time domain transmission signalx _l (t ) can be expressed as:(8) wherep _i (t ) can be a windowed subcarrier waveform, expressed as:(9) The pulse shape function is:(10) whereT _d Can be a valid symbol duration, andT _CP Can be a cyclic prefix duration. In the frequency domain,x _l (t ) can be expressed as:(11) where(12) where =T _cp +T _d Can be the entire symbol duration. In one example, for a precoding matrixG ^S The precoder value can be designed to reduce or minimize the frequency at the systemf ₁ , f ₂ , ...f _M Radiated power at the place. For example, representation X _l =[X _l ( f ₁ ) X _l (f ₂ )...X _l (f _M ) ] ^T Will cause(13) for whateverd _l Decrease or minimize,P SVD can be executed, for example,P Decomposed into:P =U∑V ^H (14) whereU Can beM×M Unit matrix,∑ Can be included in non-incremental orderP Diagonal of singular valuesM×N Matrix, andV Can be a line can bev ₁ ,v ₂ ,...v _N ofN×N Unit matrix. The precoding matrix can be chosen to:(15) IfR Defined as code redundancy, thenR=NK ,in caseR≥M , for anyd _l In terms of=0, this is due tob _l allowableP Within the zero space. Rectangular pulse OFDM can handle non-continuous pulse edges and can appear to fall tof ^-2 The relatively large power spectrum side lobes. Continuous phase OFDM signals will show a drop tof ^-4 The relatively small power spectrum side lobes provide higher spectral efficiency than rectangular pulsed OFDM signals. In an exemplary spectral precoding method, two basic set of families satisfying a continuous phase condition can be used, such as a familyW FamilyV . A corresponding precoded OFDM structure can be used to construct an OFDM signal using a base set that accompanies the input data. Family basedW _L Precoding matrixG ^WL The item can be defined as:(16) whereu=1,2...L . In equation (16),Can be presetU≥2 andAt the timev Mould 2 ^u The sum of the highest and least significant bits in the binary representation of the value (eg, in bits). Other items can be equal to zero. Based on family V _L Precoding matrixG ^V _L The item can be defined as:(17) whereu= 1,2...L . In equation (17), ifu =Log ₂ N and,then,otherwise,It can represent the least significant bit in the binary representation of v. Other items can be equal to zero. In equations (16) and/or (17)L It can be a parameter that determines the code rate. For example, the code rate can be expressed as 1-2 ^-L ,L ∈[1,Log ₂ N ]. due toG ^S ,G ^WL withG ^VL It may be a left unit matrix containing standard orthogonal columns, and the decoding matrix may be its conjugate transpose. SVD precoding matrix and spectral precoding matrix (eg useG ^WL Can be combined, for example by definitionG =G ^S G ^WL orG =G ^WL G ^S . willG defined asG =G ^S G ^WL Will cause the error to be caused when the matrix isG ^S Left multiplyG ^WL b _l Cannot have continuous phase properties. On the other hand, by choosingG =G ^WL G ^S The continuous phase genus can be maintained, and the advantage of being able to use SVD precoding can be achieved. In one example, the combined precoder can be designed as follows. Can be defined using equation (16)G ^WL Without considerationG ^S . Can be targetedPG ^WL To perform SVD (for example,PG ^WL In place of equation (14)P ), for example to determineG ^S (for example, using equation (15) to determineG ^S ). By doing this, combine precoding matricesG And the decoding matrix can be expressed as:as well as(18) Transmitted signal for spectrum precodingx _l It can be the real part of the IFFT output, and the complex part of the IFFT output can be used for SVD precoding. As shown in Figure 5, in one example, the complex portion of the IFFT output can be used. In one example, for a givenG DimensionalG ^S withG ^{W L} The matching dimensions can be decentralized, resulting in a high degree of OOB power rejection. For example, Figure 6 may be a PSD after applying spectral precoding to a 64 subcarrier OFDM system without any CP or ZP (eg, no guard (NG)) by using QPSK modulation and a 256 FFT. Figure 600. The simulation results show the same for the given case (eg NG, ZP and CP)L ,based onW _L System's PSD can outweigh V-based _L system. The code rate can be 1-2 ^-L . The five curves 602, 604, 606, 608, and 610 in FIG. 6 may show that the code rate is reduced from 1 (uncoded) to 63/64 (L When =6), the largest OOB power decrement appears. Curve 602 illustrates the PSD for an uncoded system. Curves 604, 606, 608, and 610 are respectively illustrated forL PSDs with values of 6, 5, 4, and 3. along withL Further linearly decreasing, the cumulative suppression effect can become less effective as the code rate decreases exponentially. Figure 7 is a diagram 700 showing the PSD after applying the SVD precoding method. Curve 702 illustrates the PSD for an uncoded system. Two sets of notch frequencies were used for the simulation and were referred to as near notch frequencies including [-14.5 -13.5 -12.5 -11.5 74.5 75.5 76.5 7755] and included [-35.5 -34.5 -33.5 -32.5 95.5 96.5 97.5 98.5] The far wave frequency. Curves 704 and 706 show the PSD for groups 1 and 2, respectively, when R=2. Curves 708 and 710 show the PSD for groups 1 and 2, respectively, when R=4. Curves 712 and 714 show the PSD for groups 1 and 2, respectively, when R=6. Curves 716 and 718 show the PSD for groups 1 and 2, respectively, when R=8. For the active subcarrier index of 0-63 and the FFT of size 256 in the simulation, group 1 can be close to the band and group 2 can be far away. Figure 7 shows that the allocation of the selected notch frequency can provide a trade-off between OOB power and attenuation rate. The power reduction per 1/64 code decrement does not substantially change and can be much larger than the spectral precoding when the code rate is less than 62/64. According to this observation, when the total rate is fixed tok /n When it can be taken, it will lead toK /(N -1) is assigned to the SVD precoding rate and will (N -1)/N Assigned to the spectrum precoding rate [K /(N -1),(N -1)/N The code rate pair achieves an acceptable OOB power rejection-attenuation rate level. 8 and 9 are graphs 800 showing a comparison of the SVD-based precoding method and the combined NG-OFDM precoding method for the group 1 (near notch) and group 2 (far trap) notch frequencies, respectively. And 900. Figure 8 is based on the notch frequency in Group 1 in SVD precoding and combined NG-OFDM precoding. Figure 9 is based on the notch frequency in Group 2 in SVD precoding and combined NG-OFDM precoding. In Figures 8 and 9, curves 802 and 902 show PSDs for uncoded systems. Curves 804 and 904 show the PSD of the code rate using SVD precoding for R=4. Curves 806 and 906 show the PSD for the code rate for R=3, L=6 in combination with the NG-OFDM precoding technique. Curves 808 and 908 show the PSD for the code rate of R=6 using SVD precoding. Curves 810 and 910 show the PSD for the code rate for R=5, L=6 in combination with the NG-OFDM precoding technique. Curves 812 and 912 show the PSD for the code rate of R=8 using SVD precoding. Curves 814 and 914 show the PSD for a combination of NG-OFDM precoding techniques for a code rate of R=7, L=6. Figure 8 shows that for each of the three code rates, the combined NG-OFDM precoding scheme provides approximately 15 dB less total OOB power than the SVD precoding scheme, at the expense of a slight difficulty observed in Figure 8. A wider transition zone. The transition band difference between the SVD precoding method and the combined NG-OFDM precoding scheme described herein may be larger in FIG. 9, but it is seen that the OOB power reduction using the combined NG-OFDM precoding scheme is relatively significant. 10 and 11 are graphs 1000 showing a comparison of SVD-based precoding and combined ZP-OFDM precoding methods for group 1 (near notch) and group 2 (far trap) notch frequencies, respectively. And 1100. Figure 10 is based on the notch frequency of Group 1 in the SVD precoding and combined ZP-OFDM precoding scheme. Figure 11 is based on the notch frequency of group 2 in the SVD precoding and combined ZP-OFDM precoding scheme. In Figures 10 and 11, curves 1002 and 1102 show PSDs for uncoded systems. Curves 1004 and 1104 show the PSD for a code rate of R=4 using SVD. Curves 1006 and 1106 show PSDs for a code rate of R=3, L=6 using a combined ZP-OFDM precoding scheme. Curves 1008 and 1108 show the PSD for the code rate of R=6 using SVD precoding. Curves 1010 and 1110 show PSDs for a code rate of R=5, L=6 using a combined ZP-OFDM precoding scheme. Curves 1012 and 1112 show the PSD for the code rate of R=8 using SVD precoding. Curves 1014 and 1114 show the PSD for a code rate of R=7, L=6 using a combined ZP-OFDM precoding scheme. In Figures 10 and 11, the length of the ZP can beT _d /16 (for example, 1/16 of the length of the data block). Figures 10 and 11 may behave similarly to Figures 8 and 9, for example due in part to the fact that the values on both edges of each data block before the ZP may also be zero and because In equation (14)P withV The value can be hardly changed after the ZP is added, and the continuous phase characteristics of the spectrum precoding are maintained. Figures 12 and 13 are respectively a diagram 1200 showing a comparison of SVD-based precoding and combined CP-OFDM precoding techniques for group 1 (near notch) and group 2 (far trap) notch frequencies, respectively. And 1300. Figure 12 is based on the notch frequency of group 1 in the SVD precoding method and the combined CP-OFDM precoding scheme. Figure 13 is based on the notch frequency of group 2 in the SVD precoding and combined CP-OFDM precoding scheme. In this example, the length of the CP is alsoT _d /16. Since the CP is added and the CP start edge is usually not zero, the spectrum precoding scheme will not be able to construct a continuous signal using the CP. Therefore, assigning total spectral efficiency loss to spectral precoding1/K And assign the remaining to the SVD precoding (K-1 ) /K There is no much better (if true) than all spectral efficiency losses assigned to SVD precoding alone. In Figures 12 and 13, curves 1202 and 1302 show PSDs for uncoded systems. Curves 1204 and 1304 show the PSD for the code rate of R=4 using SVD. Curves 1206 and 1306 show the PSD for a code rate of R=3, L=6 using a combined CP-OFDM precoding method. Curves 1208 and 1308 show the PSD for the code rate of R=6 using SVD precoding. Curves 1210 and 1310 show the PSD for a code rate of R=5, L=6 using a combined CP-OFDM precoding method. Curves 1212 and 1312 show the PSD for the code rate of R=8 using SVD precoding. Curves 1214 and 1314 show PSDs for a code rate of R=7, L=6 using a combined CP-OFDM precoding method. By comparing Fig. 11 and Fig. 12 with Fig. 7 to Fig. 11, it can be seen that the OOB power suppression effect for all three code rates of CP-OFDM is better than that of NG-OFDM and ZP-OFDM. difference. This may be due to the fact that in NG-OFDM and ZP-OFDM, the width of the side lobes may be equal to the frequency spacing of adjacent subcarriers. This would cause each side lob of the subcarrier to completely overlap with some or some side lobes from all other subcarriers. Therefore, in equation (14)P The singular value will drop rapidly. However, when the CP is added and the symbol duration increases, the width of the side lobes becomes narrower. therefore,P The singular value will drop more slowly. in caseP _l Is at the selected notch frequencyf _l At the average power leakage after precoding, the average power leakage after precoding can be expressed as:(19) whereP _s Can bed _l Average power and σ² (P) can beP Firsti Large singular value. In this sense, for the sameR Value, power leakage of combined CP-OFDM precoding methodP _l Can be larger than the combined NG-OFDM precoding method and/or the combined ZP-OFDM precoding methodP _l . Figure 14 shows the bit error rate (BER) of the IFFT output for the three schemes in an exemplary NG-OFDM system using QPSK modulation. The number of subcarriers may be 64 and the FFT size may be 256. In this example, the channel can be an additive white Gaussian noise (AWGN) channel, for example,,among themn _l Can represent the noise vector. SNR (dB) can be defined as:(20) Curve 1402 shows the BER of the uncoded system. Curve 1404 shows the ER for the code rate of R=4 for the system using SVD precoding. Curve 1406 shows the BER for a code rate of L=4 for a system using spectral precoding. Curve 1408 shows the BER for a code rate of R=3, L=6 using a system combining NG-OFDM precoding. Curve 1410 shows the BER for the code rate of R=6 for systems using SVD precoding. Curve 1412 shows the BER for a code rate of L=3 for a system using spectral precoding. Curve 1414 shows the BER for a code rate of R=7, L=6 using a system combining NG-OFDM precoding. In the example illustrated in Figure 14, curves 1404, 1406, and 1408 may represent systems that use substantially the same encoding rate. Similarly, curves 1410, 1412, and 1414 can represent systems that use substantially the same encoding rate. As shown in Fig. 14, when having the same code rate, the combination scheme using the far notch frequency can have almost the same BER curve as SVD precoding or spectral precoding. Furthermore, as the code rate drops, the BER can become slightly better (eg smaller) due to the fact that it can be estimated at the receiver.d _l The length of the precoding matrix can be reduced while the length of the precoding matrix can be reduced. Therefore, a lower code rate can provide a slightly higher diversity gain. Other examples of combined precoders can be employed in an OFDM system to reduce or minimize OOB power leakage. For example, an SVD precoder design can power notch at a particular frequency outside the passband to reduce or minimize out-of-band power emissions. After the SVD precoding, the N continuous precoding method can be performed. The N-continuous precoding method may employ a perturbation vector, which may depend on the current and previous symbols. Thus, N consecutive precoding can be performed such that the corresponding time domain symbols can have consecutive values and derivatives, for example at each location. Since the maximum derivative order can be increased to achieve greater OOBE rejection, other techniques or methods can be specified to achieve similar goals (eg, schemes that can suppress OOBE by obtaining continuous derivative characteristics and/or suppress OOBE by utilizing zero-space characteristics) The scheme does not have to use a large order. For example, considering that the N-continuous precoding scheme can suppress OOBE by obtaining continuous derivative characteristics and the SVD precoding scheme can suppress OOBE by utilizing zero-space characteristics, different precoding schemes can be specified to utilize both of these characteristics. For example, the combined precoding scheme can be specified to use Beck precoding for the first component precoder and N continuous precoding for the second component precoder. This technique can use precoding matrices and perturbation vectors and can provide better OOBE rejection than can be provided by Beck precoding techniques or N continuous precoding techniques. For example, one of the reasons for high OOBE may be the discontinuity of the time domain signal. Since the signals can be contiguous everywhere in the CP-OFDM symbol, the values of the left edge of the CP-OFDM symbol and its first to theJ The order derivative can be equal to the value at the right edge of the previous symbol and its first to the firstJ The order derivative solves the problem of discontinuous signal derivatives. For example, this relationship can be expressed as an adjustmentd _l ,thereby:(21) In the example, the perturbation vectorCan be used to ensure that equation (21) is satisfied (eg, to guarantee the value of the left edge of the CP-OFDM symbol and its first to the firstJ The order derivative can be equal to the value at the right edge of the previous symbol and its first to the firstJ Order derivative). Additional precoding elements can be used with the perturbation vector (e.g., when OOBE is further reduced) to satisfy equation (21). As an example, let. Can be found byTo achieve the left edge value of each left edge of each CP-OFDM symbol and its first to the firstJ The order derivative may be equal to the right edge value of the right edge of the previous CP-OFDM symbol and its first to the firstJ Order derivative, (22) where(23) and(24) due toA Can be (J +1)×N Matrix andN Can be greater than (J +1),The solution may not be unique. Possible values satisfying equations (21)-(24)Medium, with the smallest magnitudeCan be expressed asofThe Moore-Penrose pseudo-inverse (pseudoinverse) was found. If so, thenCan be expressed as:(25) At the receiver, if there is no channel effect or noise, it can be recovered correctly after the FFT process..Can be correctly estimated, thusCan be fromRemoved to recoverd _l . According to equation (25),Can depend ond _l . An iterative arithmetic decoder can be used. In the firsti Timesi ≥1) Estimated disturbance vector in iterative operationCan be expressed as:(26) where you can choose from possible frequency domain symbol vectorsTo reduce or minimize. The i-th iteration operation decision vectorCan be expressed as:(27) where. due toCan depend onb _L-1 withd _l Thus, the scheme of using the perturbation vector to reduce OOBE can be data related. If this scheme is implemented by the structure in Figure 15, then in equation (4)G =I and. The combined precoder can be designed to use the SVD precoder as the first component precoder and the N continuous precoding as the second component precoder. For example, such a combined precoding scheme can be functionally illustrated in FIG. In order to ensure that the combined scheme can take advantage of the zero-space characteristics from the SVD precoding method and the continuous derivative characteristics from the N continuous precoding method, the perturbation vector can be expressed asw _l =Gv _l . According to this relationship, equation (3) can be expressed as:(28) In order to design a combined precoder,G Can be configured asG =G ^S Without considerationv _l . Equation (28) can be substituted into equation (22), and the Moore-Penrose generalized inverse method can be used.v _l The minimum amplitude can be expressed as:(29) At the receiver,Can correspond to the firstl The recovered FFT output of the precoded frequency domain symbols. The precoded frequency domain signal can be used by the SVD decoderdeal with. makeand. After being processed by the SVD decoder,It can be processed by an iterative operation N continuous decoder. Firsti Timesi ≥1) Estimated perturbation vector of iterative operationCan be expressed as:(30) and the firsti Sub-precision operation decision vectorCan be expressed as:(31) In an example, the N-continuous precoding element precoder can operate using the selected carrier. For example, in N consecutive precoding the perturbation can be added to the data on each subcarrier. At the receiver, an iterative algorithm can be used to estimate the data being transmitted. In an example, a subset of subcarriers can be used to carry the perturbations, while the remaining subcarriers can be used to carry the data (eg, without any perturbations). At the receiver, the subcarriers with perturbations can be discarded and the remaining subcarriers can be processed in conventional OFDM data transmission. As an example, according to equation (22), the N continuous condition can be expressed as:(32) where(33) In equation (33), w _l Can be a perturbation vector without data, and d _l It can be a data vector without disturbance. Can be used in many different ways d _l with w _l To form a vectorb _l . For example, as long asb _l Any element is d _l Element or w _l Element, but not the sum of the two, vectorb _l can be used as d _l with w _l The function is expressed in a variety of ways. w _l The dimension can be (M ×1), whereM It can be the number of subcarriers that are used to carry the disturbance. d _l The dimension can be (NM ) × 1). Thus, a given subcarrier can carry perturbations or data. By substituting equation (33) into equation (32), N continuous expression can also be expressed as:(34) To understand equation (34), the following method can be used. For the first blockl =1, you can assume w _L-1 = w _o =0. Since the information is known, w _l Can be determined next (for example by equation (34)w _l =w ₁ )It is determined. For the second block,l =2, determined from the previous stepw ₁ The value can be used to calculate according to equation (34) w ₂ . The process can be determined based on the previous stepw _L-1 The value is repeated for each block. Therefore, for the firstl Block,w _l Can be determined from the previous iterationw _L-1 The value and the data to be transmitted according to equation (34) are determined. At the receiver, the subcarriers carrying the perturbations can be discarded, while the subcarriers carrying the data can be processed in the OFDM decoder. In an example, the perturbed subcarriers may be distributed rather than continuous. If the perturbed subcarriers are non-contiguous, equation (33) can be expressed accordingly. Numerical analysis can be performed to evaluate the performance of a combined precoder using a first component precoder implementing SVD precoding and a second component precoder implementing an N continuous precoder. For example, the performance of the combined precoder can be evaluated relative to a separate SVD precoder and/or a separate N continuous precoder. For example, consider a 300 subcarrier OFDM system (ie, let N = 300). For example, for subcarrier frequencies [f ₁ f ₂ ...f ₃₀₀ The subcarrier index of ] can be expressed as [-150 - 149 ... -2 -1 1 2 ... 149 150]. In the example below, 16QAM modulation can be used and the FFT size can be 1024. Figure 16 shows an exemplary PSD comparison of an SVD precoder, an N continuous precoder, and a combined precoder using SVD precoder elements and N consecutive precoding elements in the system without using a cyclic prefix (CP). . For example, the curve shows an example of a PSD for an uncoded system. Curve 1604 shows an example of a PSD for a system that uses N consecutive precoding. the termJ =1 represents that the N continuous precoder system can haveJ The maximum derivative order of =1. Curve 1606 illustrates an example of a PSD for a system that uses SVD precoding. the termR =8 represents the SVD precoder can be usedR Redundant precoding of =8. The number of notch frequencies (M ) can be selected asM =8. For example, the index of the notch frequency can be selected as [-184.5 -183.5 -182.5 -181.5 181.5 182.5 183.5 184.5]. Curve 1608 shows the useR =8 SVD precoding components andJ An example of a PSD of a combined precoder of N consecutive precoding elements of =1. In Figure 16, the CP may not be inserted (ie,T _CP =0). Compared to uncoded OFDM (e.g., curve 1602), the N-continuous precoder (e.g., curve 1604) and the SVD scheme (e.g., curve 1606) exhibit approximately 40 dB more OOBE rejection in the stop band. However, both solutions have very different attenuation performance. For example, an N-continuous scheme can have very slow attenuation and a relatively large transition band, while an SVD scheme can have a smaller transition band. Compared to the SVD scheme and the N-continuous scheme, the combined scheme can provide a relatively small transition band similar to the SVD scheme while providing a single OOBE suppression sum that is close to the two schemes. This may be because the two component schemes suppress OOBE by using two characteristics that are substantially independent of each other, such as zero space characteristics and continuous derivative characteristics. Thus, each component can be added to total OOBE rejection by utilizing different characteristics, thereby avoiding one of the component schemes from affecting other operations. Figure 17 shows an exemplary PSD of an SVD precoder, an N continuous precoder, and a combined precoder using an SVD precoder element and an N continuous precoder element in a system using a cyclic prefix (CP). Comparison. For example, curve 1702 shows an example of a PSD for an uncoded system using a CP. Curve 1704 shows the use of havingJ An example of a PSD of a N-continuous precoding system with a maximum derivative order of =1. Curve 1706 illustrates the use of having redundancy forR An example of a PSD for a SVD precoded system of =8. The number of notch frequencies (M ) can be selected asM =8. For example, the index of the notch frequency can be selected as [-184.5 -183.5 -182.5 -181.5 181.5 182.5 183.5 184.5]. Curve 1708 shows the use in a system with a CPR =8 SVD precoding components andJ An example of a PSD of a combined precoder of N consecutive precoding elements of =1. In Figure 17, the CP canT _CP =9/128T _d Was inserted. Comparing Fig. 17 with Fig. 16, it can be seen that for the SVD scheme, OOBE suppression can be reduced by 20 dB after CP insertion. The N-continuous scheme can have approximately the same OOBE rejection regardless of whether the CP is used. Furthermore, as shown in Figures 16 and 17, the combined precoding scheme can show a more significant improvement than the SVD scheme or the N continuous scheme. If CP insertion is used (eg, Figure 17), the OOBE rejection of the combined scheme may even be larger than without the CP insertion (eg, Figure 16). In the example, the four schemes shown in FIGS. 16 and 17(l The average transmit power of = 1, 2, ..., 500) can be compared. Table 1 shows a comparison of the transmission power between an SVD precoder, an N continuous precoder, and a combined precoder using an SVD precoder element and an N continuous precoder element. In the example shown in Table 1, the expectation of source material symbol power can be normalized such that the power of uncoded OFDM is equal to 1 in both cases (eg, using CP and not using CP). Since the SVD precoding matrix can be a semi-integral matrix having a coding rate of less than 1, the average transmit power of the SVD scheme can also be reduced. Comparing uncoded systems with N-continuous precoder systems, perturbation vectors in N-continuous schemesThe power increase brought can be ignored. Similarly, the perturbation vector in the combination scheme v _l The power increase brought can be a negligible small valueJ (E.gJ =1). In order to compare the peak-to-average power ratio (PAPR) performance of various precoding systems, the transmission signals of different schemes(l The supplementary cumulative distribution function (CCDF) of = 1, 2, ..., 500) can be considered. For example, Figure 18 shows a CCDF for an uncoded system, an exemplary SVD precoder, an N continuous precoder, andT _CP A combined precoder having an SVD element and an N continuous element in the case of =0. For example, curve 1802 can represent a CCDF for an uncoded system. Curve 1804 can representJ CCD N of the N continuous precoder. Curve 1806 can representR =8 SDFD precoder CCDF. Curve 1808 can representR =8 SVD precoder components andJ The CCDF of the combined precoder of the N consecutive precoder elements of =1. In the example, the lower the SVD coding rate, the higher the PAPR. Since the coding rate of the SVD scheme and the combination scheme in this example may be 292/300 ≈ 0.97, in the SVD curve (eg, curve 1806), the N continuous curve (eg, curve 1804), and the combined precoder curve (eg, curve 1808) The difference can be subtle. The bit error rate (BER) performance of different precoding systems can be estimated. For example, Figure 19 illustrates a comparison of the BER of an exemplary SVD precoder, an exemplary N continuous precoder, and a combined precoder with SVD elements and N continuous precoder elements. For example, curve 1902 can represent the BER of an uncoded system. Curve 1904 can representJ BER of the N consecutive precoder of =1. Curve 1906 can representR = 8 BER of the SVD precoder. Curve 1908 can representR =8 SVD precoder components andJ BER of the combined precoder of N consecutive precoder elements of =1. The channel can be assumed to be an AWGN channel, meaning,among themn _l Represents a noise vector. SNR (dB) can be expressed as:(35) The iterative operation decoder can be used for an N-continuous scheme and/or a combined scheme with N-continuous precoder elements. For example, the number of iterations can be set to 3, but other values can be used as well. The lower the SVD coding rate, the lower the BER. Since the coding rate here can be close to 1, the difference can be negligible. For the N-continuous scheme, the perturbation vectors are not correctly estimated during the iterative operation and are not removed for each symbol. When J is small enough (for exampleJ =1) so much so thatWhen the amplitude is extremely smaller than the minimum distance of the constellation (for example, 16QAM in this case),The errors caused by inaccurate estimates are negligible. For at least these reasons, each of the four curves in Fig. 19 can overlap almost. The simulation results show that a combined precoder scheme with multiple independent precoding elements can provide increased OOBE rejection, whether or not there is a CP, compared to a separate SVD precoding scheme or a separate N continuous precoding scheme. Since significant OOBE suppression can be achieved at the expense of very low coding rate loss (8/300 in the above simulation), the PAPR performance can be almost the same as uncoded OFDM. A small number of iterative operations and a suitable maximum derivative order setting can reduce the BER interference from the perturbation vector to a negligible level. The WTRU may consult the identity of the physical device, or the identity of a user, such as a subscription-related identity, such as an MSISDN, SIP URI, and the like. The WTRU may consult an application based identity, such as a username that may be used for each application. The processing methods described herein (e.g., combined precoding methods) may be implemented by various transmitting parties (e.g., WTRUs, base stations such as eNBs, eNBs, access points, etc.). The precoding methods described herein can be used for the uplink and/or downlink. An example wireless communication system that can employ the precoding techniques described above can employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), and frequency division multiple access (FDMA). , orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), and the like. Although features and elements have been described above in a particular combination, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in combination with other features and elements. Moreover, the embodiments described herein can be implemented in a computer process, software or firmware, which can be embodied in a computer readable medium executed by a computer or processor. Examples of computer readable media include electronic signals (transmitted over a wired or wireless connection) and computer readable storage media. Examples of computer readable storage media include, but are not limited to, read only memory (ROM), random access memory (RAM), scratchpad, cache memory, semiconductor memory device, magnetic media (eg internal hard drive) And removable disks), magneto-optical media and optical media, such as compact discs (CDs), and digital versatile discs (DVDs). A processor associated with the software is used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

100 communication system 102, 102a, 102b, 102c, 102d wireless transmit/receive unit (WTRU) 103, 104, 105 radio access network (RAN) 106, 107, 109 core network 108 public switched telephone network (PSTN) 110 Internet 112 Other Networks 114a, 114b Base Stations 115, 116, 117 Empty Intermediary 118 Processor 120 Transceiver 122 Transmitting/Receiving Elements 124 Speaker/Microphone 126 Numeric Keypad 128 Display/Touchpad 130 Non-Removable Memory 132 Removable Memory 134 Power Supply 136 Global Positioning System (GPS) Chipset 138 Peripheral Devices 140a, 140b, 140c Node B 142a, 142b Radio Network Controller (RNC) 144 Media Gateway (MGW) 146 Mobile Switching Center ( MSC) 148 Serving GPRS Support Node (SGSN) 150 Gateway GPRS Support Node (GGSN) 160a, 160b, 160c eNodeB 162 Mobility Management Entity (MME) 164 Service Gateway 166 Packet Data Network (PDN) Gateway 180a , 180b, 180c base station 182 access service network (ASN) gateway 184 mobile IP local agent (MIP-HA) 186 authentication, authorization, accounting (AAA) server 186 188 Gateway 200, 1500 Combined Precoder 202 Precoder Block 300 Transmitter 400 Receiver 500 Orthogonal Frequency Division Multiplexing (OFDM) System 502 PSK/QAM Modulation Block 504 Parallel (S/P) Conversion Block 506 Precoding Block 508 inverse fast Fourier transform (IFFT) block 510, 512, 514 block 516 efficient fast Fourier transform (FFT) block 520 serial (P/S) conversion block 522 PSK / QAM demodulation block 600, 700, 800, 900, 1000, 1100, 1200, 1300 Figures 602, 604, 606, 608, 610, 702, 704, 706, 708, 710, 712, 714, 716, 718, 802, 804, 806, 808, 810, 812, 814, 902, 904, 906, 908, 910, 912, 914, 1002, 1004, 1006, 1008, 1010, 1012, 1014, 1102, 1104, 1106, 1108, 1110, 1112, 1114, 1202, 1204, 1206, 1208, 1210, 1212, 1214, 1302, 1304, 1306, 1308, 1310, 1312, 1314, 1402, 1404, 1406, 1408, 1410, 1412, 1414, 1602, 1604, 1606, 1608, 1610, 1702, 1704, 1706, 1708, 1802, 1804, 1806, 1808, 1902, 1904, 1906, 1908 Curve BER Bit Error Rate CCDF Supplementary Cumulative Distribution Function CP Cyclic Prefix IP Internet Protocol Iub, IuCS, IuPS, iur, S1, X2 interface R1, R3, R6, R8 reference point SVD singular value decomposition ZP zero padding

A more detailed understanding of the following description can be obtained by way of example in the accompanying drawings in which: FIG. 1A is a system diagram of an example communication system in which one or more disclosed embodiments may be implemented; FIG. Is a system diagram of an exemplary wireless transmit/receive unit (WTRU) that can be used in the communication system shown in FIG. 1A; FIG. 1C is an example radio access network that can be used in the communication system shown in FIG. 1A And a system diagram of an example core network; FIG. 1D is a system diagram of another example radio access network and an example core network that may be used in the communication system shown in FIG. 1A; FIG. 1E is applicable to A system diagram of another example radio access network and an example core network in the communication system shown in FIG. 1A; FIG. 2 is a block diagram illustrating an exemplary combined precoder; A block diagram of an exemplary transmitter of a coded orthogonal frequency division multiplexing (P-OFDM) system; FIG. 4 is a block diagram illustrating an exemplary receiver of a P-OFDM system; A block diagram of an exemplary OFDM system of coding techniques; 6 is a diagram illustrating a PSD after performing a spectrum precoding method on an exemplary OFDM system; FIG. 7 is a diagram illustrating a PSD after implementing an SVD precoding method on an exemplary OFDM system; FIG. 8 is a diagram illustrating Comparison of SVD based and combined NG-OFDM for near-notched frequencies; Figure 9 is a diagram illustrating comparison of SVD based and combined NG-OFDM for near notch frequencies Figure 10 is a diagram illustrating a comparison of SVD-based and combined ZP-OFDM for near notch frequencies; Figure 11 is a comparison of SVD-based and combined ZP-OFDM for near notch frequencies Figure 12 is a diagram illustrating a comparison of SVD-based and combined CP-OFDM for near notch frequencies; Figure 13 is a diagram illustrating SVD-based and combined CP-OFDM for near notch frequencies Figure 14 is a diagram illustrating the bit error rate (BER) of the IFFT output in an exemplary NG-OFDM system; Figure 15 illustrates that the combined precoder can be used with the perturbation vector Example; Figure 16 shows the SVD precoder, N continuous precoder in a system without CP Comparing with an exemplary PSD of a combined precoder; Figure 17 illustrates an exemplary PSD comparison of an SVD precoder, an N continuous precoder, and a combined precoder in a system with CP; Figure 18 illustrates The CCDF of the uncoded system, the SVD precoder, the N continuous precoder, and the combined precoder; and Fig. 19 illustrates the comparison of the BERs of the SVD precoder, the N continuous precoder, and the combined precoder.

1500 combined precoder

Claims (20)

A combined precoder for reducing out-of-band emissions (OOBE) in a multi-carrier modulation system, the combined precoder comprising: a first precoding element configured to have a matrix based precoding scheme Applied to a data stream to generate a first precoded symbol stream; and a second precoding element configured to apply a perturbation to the first precoded symbol stream to generate a second precoding Symbolic stream. The combined precoder of claim 1, wherein the OOBE associated with the transmission of the second precoded symbol stream is less than the OOBE associated with the transmission of the uncoded transmission of the data stream. The combined precoder according to claim 1, wherein the first precoding scheme comprises a singular value decomposition (SVD) precoder scheme, an N-continuous precoding scheme or a spectrum precoding scheme. One. The combined precoder of claim 1, wherein the perturbation is transmitted on a first subcarrier group and the data symbols are transmitted on a second subcarrier group. The combined precoder of claim 4, wherein the data symbol is transmitted undisturbed on the second subcarrier group. A combined precoder as claimed in claim 1 wherein the matrix based precoding scheme reduces OOBE by utilizing a first precoding attribute and the second precoding element utilizes a different precoding attribute To reduce OOBE. The combined precoder of claim 6, wherein the first precoding attribute comprises a zero space attribute and the second precoding attribute comprises a continuous derivative attribute. A method for reducing out-of-band emissions (OOBE) in a multi-carrier modulation system, the method comprising: precoding a symbol stream using a matrix-based precoding scheme to generate a precoded symbol stream And applying a perturbation to the precoded symbol stream. The method of claim 8, wherein the OOBE associated with the transmission of the second precoded symbol stream is less than the OOBE associated with the transmission of the uncoded transmission of the data stream. The method of claim 8, wherein the first precoding scheme comprises one of a singular value decomposition (SVD) precoder scheme, an N-continuous precoding scheme, or a spectral precoding scheme. The method of claim 8, further comprising: transmitting the perturbation on a first subcarrier group; and transmitting the data symbol on a second subcarrier group. The method of claim 11, wherein the data symbol is transmitted undisturbed on the second subcarrier group. The method of claim 8, wherein the matrix-based precoding scheme reduces OOBE by utilizing a first precoding attribute, and the second precoding element reduces OOBE by utilizing different precoding attributes. The method of claim 13, wherein the first precoding attribute comprises a zero space attribute and the second precoding attribute comprises a continuous derivative attribute. An apparatus comprising: a processor; and a memory, the memory including instructions that, when executed by the processor, cause the apparatus to: precode a symbol stream using a matrix-based precoding scheme to generate a precoded symbol stream; and applying a perturbation to the precoded symbol stream. The apparatus of claim 15 wherein the OOBE associated with the transmission of the second precoded symbol stream is less than the OOBE associated with the transmission of the uncoded transmission of the data stream. The apparatus of claim 15, wherein the first precoding scheme comprises one of a singular value decomposition (SVD) precoder scheme, an N-continuous precoding scheme, or a spectral precoding scheme. The device of claim 15, wherein the memory comprises a further instruction for: transmitting the disturbance on a first subcarrier group; and transmitting on a second subcarrier group Data symbol. The apparatus of claim 15, wherein the matrix-based precoding scheme reduces OOBE by utilizing a first precoding attribute, and the second precoding element reduces OOBE by utilizing a different precoding attribute. . The apparatus of claim 19, wherein the first precoding attribute comprises a zero space attribute and the second precoding attribute comprises a continuous derivative attribute.