HK1134598A - Methods and apparatus for power allocation and/or rate selection for ul mimo/simo operations with par considerations - Google Patents

Description

Method and apparatus for power allocation and/or rate selection for UL MIMO/SIMO operation with PAR considerations

Cross Reference to Related Applications

This patent application claims priority from U.S. provisional patent application No.60/864,573 entitled "A METHOD AND PROPAPHABATUS FOR POWER ALLOCATION AND RATE SELECTION FOR MIMO/SIMO OPERATIONS WITH PAR CONSIDATIONS" filed on 11/6.2006. The foregoing application is incorporated by reference herein in its entirety.

Technical Field

The following description relates generally to wireless communications, and more particularly to providing a mechanism for power adjustment.

Background

Wireless communication systems are widely deployed to provide various communication contents such as voice, data, and so on. A typical wireless communication system may be a multiple-access system capable of supporting communication with multiple users by sharing the available system resources, such as bandwidth, transmit power … …. Examples of such multiple access systems may include: code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, frequency division multiple access (FMDA) systems, 3GPP LTE systems, Orthogonal Frequency Division Multiplexing (OFDM) systems, Localized Frequency Division Multiplexing (LFDM), Orthogonal Frequency Division Multiple Access (OFDMA) systems, and the like.

Generally, a wireless multiple-access communication system can simultaneously support communication for multiple wireless terminals. Each terminal communicates with one or more base stations via transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. This communication link may be established via a single-input single-output (SISO), multiple-input single-output (MISO), or multiple-input multiple-output (MIMO) system.

MIMO systems using multiple (N)_TMultiple) transmitting antenna and multiple (N)_RMultiple) receive antennas for data transmission. From N_TA transmitting antenna and N_RThe MIMO channel formed by the receiving antennas can be decomposed into N_SA separate channel, N can be divided_SAn independent mailThe channels are referred to as spatial channels, where N_S≤min{N_T，M_R}。N_SEach of the individual channels corresponds to a dimension. MIMO systems may provide improved performance (e.g., higher throughput and/or higher reliability) if the additional dimensionalities created by the multiple transmit and receive antennas are utilized.

MIMO systems may support Time Division Duplex (TDD) and Frequency Division Duplex (FDD) systems. In a TDD system, the forward and reverse link transmissions are on the same frequency range so that the reciprocity principle allows the estimation of the forward link channel from the reverse link channel.

In a wireless communication system, a node B (or base station) may transmit data to a User Equipment (UE) on a downlink and/or receive data from the UE on an uplink. The downlink (or forward link) refers to the communication link from the node bs to the UEs, and the uplink (or reverse link) refers to the communication link from the UEs to the node bs. The node B may also send control information (e.g., allocation of system resources) to the UE. Similarly, the UE may send control information to the node B to support data transmission on the downlink and/or for other purposes.

For an open loop MIMO system, the transmitter is unaware of the MIMO channel conditions. The optimal power distribution is a uniform distribution of power along all transmit antennas. With limited feedback, such as the rate that each stream can support, rate matching, and Minimum Mean Square Error (MMSE) detection and successive interference cancellation (SIC, collectively referred to as MMSE-SIC), the receiver can be proven to be a solution to achieve performance. This is the basis of PARC (per antenna rate control) systems. An alternative MIMO scheme includes layer permutation, which effectively equalizes four spatial channels. Since the layer permutation is unitary transform (unitary permutation transformation), it can be easily seen that the scheme is also realizable performance. In practice, this is the basis for VAP (virtual antenna permutation). In these schemes, equal power allocation is used at the transmitter.

However, for upload or Uplink (UL) MIMO transmission, equal power allocation is no longer feasible because of peak-to-average limitations to be taken into account. Transmitting the same maximum power from all transmit antennas drives some amplifiers into their non-linear region and results in higher signal distortion.

Disclosure of Invention

The following presents a simplified summary of one or more embodiments in order to provide a basic understanding of such embodiments. This summary is not an extensive overview of all contemplated embodiments, and is intended to neither identify key or critical elements of all embodiments nor delineate the scope of such embodiments. Its sole purpose is to present some concepts of one or more embodiments in a simplified form as a prelude to the more detailed description that is presented later.

According to one aspect, a method for a wireless communication system comprises: receiving a peak-to-average ratio (PAR) back-off value; a power value, such as a Power Allocation (PA) value, is determined using the received PAR back off value. According to one aspect, the PAR back off value is based at least in part on a modulation type. In another aspect, the method includes determining a UL transmission rate. In another aspect, the PAR back off value is based at least in part on the modulation type and is greater for 64QAM than for QPSK. The power allocation algorithm for different UL MIMO is described as follows. Power Allocation (PA) without antenna permutation (e.g. per antenna rate control PARC): different PAR back off values for different modulation schemes can be considered when allocating power for different antenna streams. For different modulations, e.g., QPSK and 16QAM, different PA back-offs should be used. Thus, if different modulation orders are used for different layers, the power allocation will be different. Power allocation with antenna permutation (e.g. virtual access point VAP): if the same modulation order is selected for different layers, the PA back-off can be selected according to the back-off factor for that modulation order. If a different modulation order is selected, the PA back-off may be selected based on the PAR back-off value from the permutated stream.

In one aspect, a rate determination algorithm that takes PAR into account is described as follows. In one aspect, a centralized rate determination controlled by a node B scheduler is considered. Power control is used for Channel Quality Indicator (CQI) from one antenna as a reference signal. The channel conditions from the other antennas can be derived based on the broadband pilot from all antennas or based on the specific design of the request channel. In other words, MIMO channel sounding is achieved by periodically transmitting broadband pilots from all antennas or by transmitting request channels from different antennas. The broadband pilot symbols may be used by the access terminal to generate Channel Quality Information (CQI) regarding the channel between the access terminal and the access point for the channel between each transmit antenna that transmits the symbols and the receive antenna that receives the symbols. In one embodiment, the channel estimate may constitute noise, signal-to-noise ratio, pilot signal power, fading, delay, path loss, shadowing, correlation, or any other measurable characteristic of the wireless communication channel. The UE reports a delta Power Spectral Density (PSD) relative to a reference signal within the headroom, which is adjusted by the load indicator taking into account path differences of the serving sector and other sectors. To be consistent with SIMO operation, the Δ PSD of the antenna transmitting the CQI signal may be reported back. By assuming QPSK transmission, PA backoff in case of PAR consideration can be determined. Node B uses this reported Δ PSD to calculate the data rate for users that have not experienced inter-user interference (e.g., the last decoded user in SIC operation). If the selected modulation is higher than QPSK, additional backoff should be applied and the supportable rate recalculated. The node B can calculate the data rate of the user suffering from inter-user interference based on the effective signal-to-noise ratio (SNR) after SIC. If the modulation order is higher than QPSK, according to one scheme, additional back-off can be applied and the supportable rate can be recalculated.

Some central ideas in general include: a) applying different transmission powers, PAR back off depending at least on the modulation order used for SIMO and MIMO users; and b) the transmission power for each MIMO stream and the rate that can be supported by the different streams also depend on the various MIMO transmissions, e.g., per antenna rate control, antenna permutation, or other unitary transformations such as virtual antenna mapping.

To the accomplishment of the foregoing and related ends, the one or more embodiments comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative aspects of the one or more embodiments. These aspects are indicative, however, of but a few of the various ways in which the principles of various embodiments may be employed and the described embodiments are intended to include all such aspects and their equivalents.

Drawings

Fig. 1 illustrates a wireless communication system in accordance with various aspects set forth herein.

Fig. 2 is a block diagram of an embodiment of a transmitter system (also referred to as an access point) and a receiver system (also referred to as an access terminal) in a MIMO system according to one or more aspects.

Fig. 3 illustrates a block diagram of an UL MIMO transceiver in accordance with one or more aspects.

Fig. 4 depicts an exemplary access terminal capable of providing feedback to a communication network in accordance with one or more aspects.

FIG. 5 illustrates an example of a suitable computing system environment in accordance with one or more aspects.

FIG. 6 provides a schematic diagram of an exemplary networked or distributed computing environment in which PAR back-off may be used in accordance with one or more aspects.

Fig. 7 illustrates a wireless communication system with multiple base stations and multiple terminals, such as may be utilized in conjunction with one or more aspects of PAR back off as described herein.

Fig. 8 is an illustration of an ad hoc or unplanned/semi-planned wireless communication environment according to various aspects of PAR back off as described herein.

Figure 9 illustrates a method comprising receiving a PAR back off value in accordance with one or more aspects.

Fig. 10 illustrates a methodology 1000 in accordance with one or more aspects wherein power control is employed for Channel Quality Indicator (CQI) from one antenna as a reference signal.

Fig. 11 illustrates a methodology in accordance with one or more aspects in which a source node-B communicates with a mobile device.

Fig. 12 illustrates an environment in which a node B, e.g., source node B1202, communicates with a mobile device in accordance with one or more aspects.

Fig. 13 illustrates PAR for LFDM for 16QAM and QPSK according to one or more aspects.

Fig. 14 illustrates PAR for LFDM for 64QAM and QPSK according to one or more aspects.

Fig. 15 shows PAR for LFDM combined with one or more aspects for 64QAM and 16 QAM.

Detailed Description

Various aspects are now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. It may be evident, however, that such aspect(s) may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more aspects.

According to one aspect, a method for a wireless communication system comprises: receiving a peak-to-average ratio (PAR) back-off value; and using the received PAR back off value to determine a power value. According to one aspect, the PAR back off value is based at least in part on a modulation type. In another aspect, the method includes determining a rate of UL transmissions. In another aspect, the PAR back off value is based at least in part on a modulation type, and the PAR back off value for 64QAM is greater than for QPSK. The power allocation algorithm for the different UL MIMO schemes is described as follows. Power allocation PA without antenna permutation (e.g. per antenna rate control PARC): different PAR back off values for different modulation schemes can be considered when allocating power for different antenna streams. Different PA back-offs may be applied for different modulations, such as QPSK and 16 QAM. Thus, if different modulation orders are used for different layers, the power allocation will be different. Power allocation with antenna permutation (e.g. virtual access point VAP): if the same modulation order is selected for different layers, the PA back-off can be selected according to the back-off factor for that modulation order. If a different modulation order is selected, the PA back-off may be selected based on the PAR back-off value from the permutated stream.

In one aspect, a rate determination algorithm with a PAR back-off value taken into account is described as follows. In one aspect, a centralized rate determination controlled by a node B scheduler is considered. Power control is used for the channel quality indicator CQI from one antenna as a reference signal. The channel conditions from the other antennas can be derived based on the broadband pilot from all antennas or based on the specific design of the request channel. In other words, MIMO channel sounding is achieved by periodically transmitting broadband pilots from all antennas, or transmitting request channels from different antennas. The broadband pilot symbols may be used by the access terminal to generate Channel Quality Information (CQI) regarding the channel between the access terminal and the access point for the channel between each transmit antenna that transmits the symbols and the receive antenna that receives the symbols. In one embodiment, the channel estimate may constitute noise, signal-to-noise ratio, pilot signal power, fading, delay, path loss, shadowing, correlation, or any other measurable characteristic of the wireless communication channel. The UE reports a delta Power Spectral Density (PSD) relative to a reference signal within the headroom, which is adjusted by the load indicator taking into account path differences of the serving sector and other sectors. To be consistent with SIMO operation, the Δ PSD of the antenna transmitting the CQI signal may be reported back. By assuming QPSK transmission, PA back-off can be determined considering PAR back-off values. Node B uses this reported Δ PSD to calculate the data rate for users that have not experienced inter-user interference (e.g., the last decoded user in SIC operation). If the selected modulation is higher than QPSK, additional backoff can be applied and the supportable rate can be recalculated. The node B can calculate the data rate of the user suffering from inter-user interference based on the effective signal-to-noise ratio (SNR) after SIC. If the modulation order is higher than QPSK, according to one scheme, additional back-off can be applied and the supportable rate can be recalculated. By "back off" is meant any magnitude less than the full magnitude available.

In addition, a plurality of aspects of the present disclosure are explained below. It should be apparent that the teachings herein may be embodied in a wide variety of forms and that any specific structure and/or function disclosed herein is merely representative. Based on the teachings herein one skilled in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number of the aspects set forth herein. In addition, an apparatus may be implemented and/or a method practiced using other structure and/or functionality in addition to or in addition to one or more of the aspects set forth herein. For example, many of the methods, apparatus, systems, and devices described herein are presented in the context of an ad-hoc or unplanned/semi-planned deployed wireless communication environment that provides for a repeated ACK channel in an orthogonal system. Those skilled in the art will recognize that similar techniques may be used in other communication environments.

As used in this application, the terms "component," "system," and the like are intended to refer to a computer-related entity, either hardware, software in execution, firmware, middleware, microcode, and/or any combination thereof. For example, a component may be, but is not limited to: a process running on a processor, an object, an executable, a thread of execution, a program, and/or a computer. One or more components can reside within a process and/or thread of execution and a component can be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets (e.g., data from one component interacting with another component in a local system, distributed system, and/or across a network such as the internet with other systems by way of the signal). Additionally, components of systems described herein may be rearranged and/or complimented by additional components in order to facilitate achieving the various aspects, goals, advantages, etc., described with regard thereto, and are not limited to the precise configurations set forth in a given figure, as will be appreciated by one skilled in the art.

Moreover, various aspects are described herein in connection with a subscriber station. A subscriber station can also be called a system, a subscriber unit, mobile station, mobile, remote station, remote terminal, access terminal, user agent, user device, or user equipment. A subscriber station may be a cellular telephone, a cordless telephone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device having wireless connection capability, or other processing device connected to a wireless modem or similar mechanism for facilitating wireless communication with a processing device.

Moreover, various aspects or features described herein may be implemented as a method, apparatus, article of manufacture using standard programming and/or engineering techniques. The term "article of manufacture" as used herein is intended to encompass a computer program accessible from any computer-readable device, carrier, or media. For example, computer-readable media may include, but are not limited to: magnetic storage devices (e.g., hard disks, floppy disks, magnetic strips, etc.), optical disks (e.g., Compact Disks (CDs), Digital Versatile Disks (DVDs), etc.), smart cards, and flash memory devices (e.g., cards, sticks, key drives, etc.). In addition, various storage media described herein can represent one or more devices and/or other machine-readable media for storing information. The term "machine-readable medium" can include, without being limited to, wireless channels and various other media capable of storing, containing, and/or carrying instruction(s) and/or data.

Furthermore, the word "exemplary" is used herein to mean serving as an embodiment, example, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the word exemplary is intended to provide concepts in a concrete fashion. As used in this application, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless specified otherwise, or clear from context, "X employs A or B" is intended to mean any of the inherent inclusive permutations. That is, if X employs A; b is used as X; or X employs A and B, then "X employs A or B" is satisfied under any of the foregoing circumstances. In addition, the articles "a" and "an" as used in this application and the appended claims should generally be construed to mean "one or more" unless specified otherwise or clear from context to be directed to a singular form.

As used herein, the term to "infer" or "inference" refers generally to the process of reasoning about or inferring states of the system, environment, and/or user from a set of observations as captured via events and/or data. Inference can be employed to identify a specific context or action, or can generate a probability distribution over states, for example. Such inference can be probabilistic-that is, the computation of a probability distribution over states of interest based on a consideration of data and events. Inference can also refer to techniques employed for composing higher-level events from a set of events and/or data. Such inference results in the construction of new events or actions from a set of observed events and/or stored event data, whether or not the events are correlated in close temporal proximity, and whether the events and data come from one or several event and data sources.

The transmission enhancement techniques described herein may be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, single-carrier frequency division multiplexing (SC-FDMA) systems. The terms "system" and "network" are often used interchangeably. A CDMA system may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), CDMA2000, etc. UTRA includes wideband CDMA (W-CDMA) and Low Chip Rate (LCR). cdma2000 covers IS-2000, IS-95 and IS-856 standards. TDMA systems may implement radio technologies such as global system for mobile communications (GSM). OFDMA systems may implement radio technologies such as evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, Flash-OFDMA, and the like. These various radio technologies and standards are well known in the art.

UTRA, E-UTRA and GSM are part of the Universal Mobile Telecommunications System (UMTS). Long Term Evolution (LTE) is an upcoming release of UMTS using E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents of the organization entitled "third Generation partnership project" (3 GPP). Cdma2000 is described in a document entitled "third Generation partnership project 16" (3GPP 2). For clarity, certain aspects of these techniques are described below for uplink transmission in LTE, using 3GPP terminology in much of the description below.

LTE uses Orthogonal Frequency Division Multiplexing (OFDM) on the downlink and single carrier frequency division multiplexing (SC-FDMA) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (N) orthogonal subcarriers, which are also often referred to as tones, bins (bins), and so on. Each subcarrier may be modulated with data. Typically, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. For LTE, the spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (N) may depend on the system bandwidth. In one design, N is 512 for a system bandwidth of 5MHz, 1024 for a system bandwidth of 10MHz, and 2048 for a system bandwidth of 20 MHz. In general, N may be any integer value.

The system may support a Frequency Division Duplex (FDD) mode and/or a Time Division Duplex (TDD) mode. In FDD mode, separate frequency channels may be used for the downlink and uplink, and downlink and uplink transmissions may be sent simultaneously on their separate frequency channels. In TDD mode, a common frequency channel may be used for the downlink and uplink, downlink transmissions may be sent in some time periods, and uplink transmissions may be sent in other time periods. The LTE downlink transmission scheme is divided by radio frames (e.g., 10ms radio frames). Each frame includes a pattern of frequencies (e.g., subcarriers) and time (e.g., OFDM symbols). A 10ms radio frame is divided into a plurality of adjacent.5 ms subframes (also referred to as subframes or slots, hereinafter used interchangeably). Each subframe includes a plurality of resource blocks, where each resource block is comprised of one or more subcarriers and one or more OFDM symbols. One or more resource blocks may be used for transmitting data, control information, pilot, or any combination thereof.

A multicast/broadcast single frequency network or MBSFN is a broadcast network in which several transmitters simultaneously transmit the same signal on the same frequency channel. Analog FM and AM radio networks and digital broadcast networks may operate in the same manner. Since MBSFN results in ghost (ghost) due to echoes of the same signal, analog television transmission proves to be more difficult.

A simplified form of MBSFN may be implemented by means of a low power co-channel repeater, booster, or broadcast converter acting as a gap filler transmitter. The goal of SFN is to efficiently utilize the radio spectrum, allowing a greater number of radio and TV programs than traditional multi-frequency network (MFN) transmissions. MBSFN may also increase coverage area and reduce outage probability compared to MFN, since total received signal strength may increase to an intermediate position between transmitters.

MBSFN schemes are somewhat similar to non-broadcast wireless communication, such as those in cellular networks and wireless computer networks known as transmitter macro diversity, CDMA soft handover, and Dynamic Single Frequency Networks (DSFN). MBSFN transmission can be considered as a strict form of multipath propagation. The radio receiver receives several echoes of the same signal, between which beneficial or harmful interference (also called self-interference) can lead to fading. This is particularly problematic in wideband communications and high data rate digital communications, since fading in this case is frequency selective (as opposed to flat fading) and the time spread of the echo can lead to inter-symbol interference (ISI). Fading and ISI can be avoided by means of diversity schemes and equalization filters.

In wideband digital broadcasting, PFDM or COFDM modulation methods help self-interference cancellation. OFDM uses a large number of slow low bandwidth modulators instead of one fast wideband modulator. Each modulator has its own frequency subchannel and subcarrier frequency. Since each modulator is very slow, a guard interval can be inserted between symbols, thereby eliminating ISI. Although fading is frequency selective over the entire frequency channel, it can be considered flat within the narrowband subchannel. Thus, the use of advanced equalization filters can be avoided. Forward error correction codes (FEC) are able to counteract the situation where a particular part of the sub-carriers is subject to too much fading to be correctly demodulated.

Referring to fig. 1, a multiple access wireless communication system according to one embodiment is shown. An access point 100(AP) includes multiple antenna groups, one including 104 and 106, another including 108 and 110, and an additional including 112 and 114. Although only two antennas are shown in fig. 1 for each antenna group, more or fewer antennas may be utilized for each antenna group. Access terminal 116(AT) is in communication with antennas 112 and 114, where antennas 112 and 114 transmit information to access terminal 116 over forward link 120 and receive information from access terminal 116 over reverse link 118. Access terminal 122 is in communication with antennas 106 and 108, where antennas 106 and 108 transmit information to access terminal 122 over forward link 126 and receive information from access terminal 122 over reverse link 124. Access terminals 116 and 122 can be UEs. In a FDD system, communication links 118, 120, 124 and 126 may use different frequency for communication. For example, forward link 120 may use a different frequency than reverse link 118.

Each group of antennas and/or the area in which they are designed to communicate is often referred to as a sector of the access point. In this embodiment, antenna groups each are designed to communicate to access terminals in a sector, of the areas covered by access point 100.

In communicating over forward links 120 and 126, the transmitting antennas of access point 100 employ beamforming in order to improve the signal-to-noise ratio of forward links for the different access terminals 116 and 124. Moreover, an access point using beamforming to transmit to access terminals scattered randomly through its coverage causes less interference to access terminals in neighboring cells than an access point transmitting through a single antenna to all its access terminals.

An access point may be a fixed station used for communicating with the terminals and may also be referred to as an access point, a node B, or some other terminology. An access terminal may also be called an access terminal, User Equipment (UE), a wireless communication device, terminal, access terminal, or some other terminology.

Fig. 2 is a block diagram of an embodiment of a transmitter system 210 (also referred to as an access point) and a receiver system 250 (also referred to as an access terminal) in a MIMO system 200. At the transmitter system 210, traffic data for a number of data streams is provided from a data source 212 to Transmit (TX) data processor 214.

In one embodiment, each data stream is transmitted over a respective transmit antenna. TX data processor 214 formats, codes, and interleaves the traffic data for each data stream based on a particular coding scheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot data using OFDM techniques. The pilot data is typically a known data type that is processed in a known manner and is used at the receiver system to estimate the channel response. The multiplexed pilot and coded data for each data stream is then modulated (i.e., symbol mapped) based on a particular modulation scheme (e.g., BASK, ASK, M-PSK, or M-QAM) selected for that data stream to provide modulation symbols. The data rate, coding, and modulation for each data stream may be determined by instructions performed by processor 230.

The modulation symbols for all data streams are then provided to a TX MIMO processor 220, and the modulation symbols may be further processed (e.g., for OFDM) by the TX MIMO processor 220. TX MIMO processor 220 then forwards N_TA plurality of transmitters (TMTR)222a through 222t provide N_TA stream of modulation symbols. In a particular embodiment, TX MIMO processor 220 applies beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.

Each transmitter 222 receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. Then from N respectively_TN from transmitters 222a through 222t are transmitted by antennas 224a through 224t_TA modulated signal.

At the receiver system 250, the transmitted modulated signal is composed of N_REach antenna 252a through 252r receives a signal and provides a received signal from each antenna 252 to a respective receiver (RCVR)254a through 254 r. Each receiver 254 conditions (e.g., filters, amplifies, and downconverts) a respective received signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding "received" symbol stream.

RX data processor 260 then goes from N_RA receiver 254 receiving N_RA stream of received symbols and processing the N based on a particular receiver processing technique_RA stream of received symbols to provide N_TA "detected" symbol stream. RX data processor 260 then demodulates, deinterleaves, and deinterleavesEach detected symbol stream is coded to recover traffic data for the data stream. The processing by RX data processor 260 is complementary to that performed by TX MIMO processor 220 and TX data processor 214 at transmitter system 210. A processor 270 periodically determines which pre-coding matrix to use. Processor 270 formulates a reverse link message comprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of information regarding the communication link and/or the received data stream. The reverse link message is then processed by a TX data processor 238, and traffic data for a number of data streams from a data source 236 is received by TX data processor 238, modulated by a modulator 280, conditioned by transmitters 254a through 254r, and transmitted back to transmitter system 210.

At transmitter system 210, the modulated signals from receiver system 250 are received by antennas 224, conditioned by receivers 222, demodulated by a demodulator 240, and processed by a RX data processor 242 to extract the reserve link message transmitted by receiver system 250. Processor 230 then determines which pre-coding matrix to use for determining the beamforming weights then processes the extracted message.

In one aspect, logical channels are classified into control channels and traffic channels. Logical control channels include a Broadcast Control Channel (BCCH), which is a DL channel for broadcasting system control information. The Paging Control Channel (PCCH) is a DL channel for transferring paging information. The Multicast Control Channel (MCCH) is a point-to-multipoint DL channel that transmits Multimedia Broadcast and Multicast Service (MBMS) scheduling and control information for one or several MTCHs. Typically, this channel is only used by UEs receiving MBMS after a Radio Resource Control (RRC) connection is established. Dedicated Control Channel (DCCH) is a point-to-point bi-directional channel that transmits dedicated control information and is used by UEs having an RRC connection. In one aspect, the logical traffic channels include a Dedicated Traffic Channel (DTCH), which is a point-to-point bi-directional channel, dedicated to one UE, and used for the transfer of user information. In addition, a Multicast Traffic Channel (MTCH) for a point-to-multipoint DL channel is used to transmit traffic data.

In one aspect, transport channels are classified as DL and UL. DL transport channels include a Broadcast Channel (BCH), downlink shared data channel (DL-SDCH) and a Paging Channel (PCH), the PCH for support of UE power saving (DRX cycle is indicated by the network to the UE), broadcast over the entire cell and mapped to PHY resources that can also be used for other control/traffic channels. The UL transport channels include a Random Access Channel (RACH), a request channel (REQCH), an uplink shared data channel (UL-SDCH), and a plurality of PHY channels. The PHY channels include a set of DL channels and UL channels.

The DL PHY channels include:

common pilot channel (CPICH)

Synchronization Channel (SCH)

Common Control Channel (CCCH)

Shared DL Control Channel (SDCCH)

Multicast Control Channel (MCCH)

Shared UL distribution channel (SUACH)

Acknowledgement channel (ACKCH)

DL physical shared data channel (DL-PSDCH)

UL Power Control Channel (UPCCH)

Paging Indicator Channel (PICH)

Load Indicator Channel (LICH)

The UL PHY channels include:

physical Random Access Channel (PRACH)

Channel Quality Indicator Channel (CQICH)

Acknowledgement channel (ACKCH)

Antenna Subset Indicator Channel (ASICH)

Shared request channel (SREQCH)

UL physical shared data channel (UL-PSDCH)

Broadband pilot channel (BPICH)

In one aspect, a channel structure is provided that maintains low signal to Peak Average (PAR) values and the channel is continuous or uniformly spaced in frequency at any given time, which is a desirable characteristic of a single carrier waveform.

Fig. 3 illustrates a block diagram 300 of a UL MIMO transceiver, which shows a plurality of M-point DFT blocks 302 that perform discrete Fast Fourier Transforms (FFTs) and a plurality of subcarrier mapping blocks 304 that perform subcarrier mapping. MIMO transmitter processing is shown at block 306. Multiple N-point IFFT blocks at 308, inverse FFT is performed in 308, and two sets of nodes 310 and 312 are located between the N-point inverse FFT block 308 and the multiple FFT performed N-point FFT block 314. MIMO transmitter processing is shown at block 316, and multiple M-point IDFT blocks at 318, can perform an inverse DFT at 318.

For SC-FDM, the transmitted signal is generated in the time domain and converted into the frequency domain by an M-point Discrete Fourier Transform (DFT) operation. For OFDM, the DFT block 302 is bypassed. To focus on the impact of MIMO operation, only LFDM, which is most relevant for UL data transmission, may be considered for SC-FDM. Such modeling can be readily extended to include inverse fast fourier transform demodulation (IFDM), if desired. For MIMO operation, different types of permutation patterns may be considered for OFDM and LFDM: 1. MIMO transmission without antenna permutation. 2. MIMO transmission with symbol level permutation: the transmission streams are permuted on a symbol basis during each Transmission Time Interval (TTI). By permutation at the symbol level, it is meant that the transport stream is permuted for each of the 6 LFDM symbols within the 0.5ms slot of the E-UTRA uplink transmission. For simplicity, simulation results are provided for only 2 × 2 MIMO. However, extension to 4 x 4 is trivial. For MIMO transmission, two streams with the same or different modulation orders may be considered. QPSK and 16QAM are selected as UL modulation orders based on the current lte-UTRA specification. It is highly likely that for the two transmit antenna case, 16QAM is used as the modulation order for one stream and QPSK is used as the modulation order for the other stream. Alternatively, in some cases, 16QAM is used for both streams. If the current MCS is extended to include 64QAM, a combination of 64QAM with QPSK or 16QAM is also available. In the present application, the following three cases with mixed modulation orders can be considered.

	First stream	Second stream
			Case 1	16QAM	QPSK
Case 2	64QAM	QPSK
			Case 3	64QAM	16QAM

TABLE 1 modulation order for 2 × 2MIMO UL PAR simulation

The Fast Fourier Transform (FFT) size considered is N_fftThe DFT size considered is N512_dft100 tones. Will be N in total_guardGuard tones of 212 tones are symmetrically inserted on both sides of the 300 data tones. Finally, the localized frequency tones are mapped to the first N_dftThe data tone location. Typically the PAR back off is such that 64QAM>16QAM>QPSK。

Fig. 4 depicts an exemplary access terminal 400 capable of providing feedback to a communication network in accordance with one or more aspects of PAR back off and/or PA back off as described herein. Access terminal 400 includes a receiver 402, e.g., an antenna, that receives a signal and performs conventional operations (e.g., filters, amplifies, downconverts, etc.) on the received signal. In particular, receiver 402 can also receive a service schedule defining services allocated for transmission of one or more blocks of an allocation time period, a schedule associating blocks of downlink resources with blocks of uplink resources to provide feedback information as described herein, and/or the like. Receiver 402 can comprise a demodulator 404 that can demodulate received symbols and provide them to a processor 406 for evaluation. Processor 406 may be a processor dedicated to analyzing information received by receiver 402 and/or generating information for transmission by a transmitter 416. Further, processor 406 can be a processor that controls one or more components of access terminal 400 and/or a processor that analyzes information received by receiver 402, generates information for transmission by transmitter 416, and controls one or more components of access terminal 400. Additionally, processor 406 may execute instructions for interpreting an association of uplink resources and downlink resources received by receiver 402, determining non-received downlink blocks, or generating a feedback message, such as a bitmap, suitable for conveying such non-received blocks, or for analyzing a hash function to determine an appropriate uplink resource of a plurality of uplink resources as described herein.

The access terminal 400 can also include memory 408 that is operatively coupled to the processor 406 and that can store data to be transmitted, received, and the like. Memory 408 can store information related to downlink resource scheduling, protocols for evaluating previous information, for determining protocols for non-received portions of transmissions to determine illegible transmissions, for sending feedback messages to access points, and the like.

It will be appreciated that the data store (e.g., memory 408) described herein can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. By way of example, and not limitation, nonvolatile memory can include Read Only Memory (ROM), programmable ROM (prom), electrically programmable ROM (eprom), electrically erasable prom (eeprom), or flash memory. Volatile memory can include Random Access Memory (RAM), which acts as external cache memory. By way of example, and not limitation, RAM may take many forms, such as Synchronous RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), Enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and Direct Rambus RAM (DRRAM). The memory 408 of the claimed system and method is intended to comprise, without being limited to, these and any other suitable types of memory.

The receiver 402 is also operatively coupled to a multiplexing antenna 410 that can receive scheduled associations between one or more additional blocks of downlink resources and blocks of uplink resources. A multiplexing processor 406 may be provided. Further, the calculation processor 412 can receive a feedback probability function that limits the probability of providing a feedback message by the access terminal 400 if a block of downlink transmission resources or data associated therewith is not received, as described herein.

Access terminal 400 also comprises a modulator 414 and a transmitter 416, where transmitter 416 transmits signals to, for example, a base station, an access point, another access terminal, a remote agent, etc. Although signal generator 410 and indicator evaluator 412 are depicted as being separate from processor 406, it can be appreciated that signal generator 410 and indicator evaluator 412 can be part of processor 406 or multiple processors (not shown).

While, for purposes of simplicity of explanation, the methodologies are shown and described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts may, in accordance with the claimed subject matter, occur in different orders and/or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate that a methodology could alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all illustrated acts may be required to implement a methodology in accordance with the claimed subject matter.

For a multiple-access system (e.g., FDMA, OFDMA, CDMA, TDMA, etc.), multiple terminals may transmit simultaneously on the uplink. For such a system, the pilot subbands may be shared among different terminals. The channel estimation technique may be used in cases where the pilot subbands for each terminal span the entire operating band (possibly except for the band edges). This pilot subband structure is desirable to obtain frequency diversity for each terminal. The techniques described herein may be implemented by various means. For example, these techniques may be implemented in hardware, software, or a combination thereof. For a hardware implementation, which may be digital, analog, or digital and analog, the processing units used for channel estimation may be implemented within one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. By means of software, through modules (e.g., procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in memory units and executed by processors.

It is to be understood that the embodiments described herein may be implemented in hardware, software, firmware, middleware, microcode, or any combination thereof. For a hardware implementation, the processing units may be implemented within one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof.

FIG. 5 illustrates an example of a suitable computing system environment 500a in which the application may be implemented, although as made clear above, the computing system environment 500a is only one example of a suitable computing environment and is not intended to suggest any limitation as to the scope of use or functionality of the application. Neither should the computing environment 500a be interpreted as having any dependency or requirement relating to any one or combination of components illustrated in the exemplary operating environment 500 a.

With reference to FIG. 5, an exemplary remote device for implementing at least one general non-limiting embodiment includes a general purpose computing device in the form of a computer 510 a. The components of computer 510a may include, but are not limited to: a processing unit 520a, a system memory 530a, and a system bus 525a, the system bus 525a coupling the various system components including the system memory to the processing unit 520 a. The system bus 525a may be any of several types of bus structures including: a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures.

The computer 510a typically includes a variety of computer readable media capable of storing modulation based on PA and/or PAR back off values. Computer readable media can be any available media that can be accessed by computer 510 a. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media include, but are not limited to: computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CDROM, Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can accessed by computer 510 a. Communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media.

The system memory 530a may include computer storage media in the form of volatile and/or nonvolatile memory such as Read Only Memory (ROM) and/or Random Access Memory (RAM). A basic input/output system (BIOS), containing the basic routines that help to transfer information between elements within computer 510a, such as during start-up, may be stored in memory 530 a. Memory 530a also typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit 520 a. By way of example, and not limitation, memory 520a may also include an operating system, application programs, other program modules, and program data.

The computer 510a may also include other removable/non-removable, volatile/nonvolatile computer storage media. For example, computer 510a may include: a hard disk drive that reads from or writes to non-removable, nonvolatile magnetic media; a disk drive that reads from or writes to a removable, nonvolatile disk; and/or an optical disk drive that reads from or writes to a removable, nonvolatile optical disk such as a CD ROM or other optical media. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to: magnetic cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. A hard disk drive is typically connected to the system bus 525a through a non-removable memory interface (e.g., an interface), and a magnetic disk drive or optical disk drive is typically connected to the system bus 525a by a removable memory interface (e.g., an interface).

A user may enter commands and information into the computer 510a through input devices such as a keyboard and pointing device, commonly referred to as a mouse, trackball or touch pad. Other input devices may include: a microphone, joystick, game pad, satellite dish (satellite dish), scanner, or the like. These and other input devices are often connected to the processing unit 520a through a user input 540a and an associated interface that are coupled to the system bus 525a, but may be connected by other interface and bus structures, such as a parallel port, game port or a Universal Serial Bus (USB). A graphics subsystem may also be connected to system bus 525 a. A monitor or other type of display device can also be connected to the system bus 525a via an interface, such as output interface 550a, which in turn can communicate with video memory. In addition to the monitor, computers may also include other peripheral output devices such as speakers and a printer, which may be connected through output interface 550 a.

The computer 510a may operate in a networked environment or a distributed environment using logical connections to one or more other remote computers, such as a remote computer 570a, which in turn may have different media capabilities than the device 510 a. The remote computer 570a may be a personal computer, a server, a router, a network PC, a peer device or other common network node, or any other remote media consumption or transmission device, and may include any or all of the elements described above relative to the computer 510 a. The logical connections depicted in fig. 5 include a network 580a, such Local Area Network (LAN) or a Wide Area Network (WAN), but may also include other networks/buses. Such networking environments are commonplace in homes, offices, enterprise-wide computer networks, intranets and the Internet.

When used in a LAN networking environment, the computer 510a is connected to the LAN 580a through a network interface or adapter. When used in a WAN networking environment, the computer 510a typically includes a communication component, such as a modem, or other means for establishing communications over the WAN, such as the Internet. A communications component, such as a modem, which may be internal or external, may be connected to the system bus 525a via the user input interface of input 540a, or other appropriate mechanism. In a networked environment, program modules depicted relative to the computer 510a, or portions thereof, may be stored in the remote memory storage device. It will be appreciated that the network connections shown and described are exemplary and other means of establishing a communications link between the computers may be used.

Fig. 6 provides a schematic diagram of an exemplary networked or distributed computing environment in which PAR back-off and/or PA back-off may be used. The distributed computing environment comprises computing objects 610a, 610b, etc. and computing objects or devices 620a, 620b, 620c, 620d, 620e, etc. These objects may include programs, methods, data storage, programmable logic, and the like. The object may comprise multiple parts of the same or different devices, such as: PDAs, audio and/or video devices, MP3 players, personal computers, and the like. Each object may communicate with another object by way of a communication network 640. This network may itself comprise other computing objects and computing devices for providing services to the system of FIG. 6, and may itself represent multiple interconnected networks. In accordance with one aspect of at least one general non-limiting embodiment, each object 610a, 610b, etc. or 620a, 620b, 620c, 620d, 620e, etc. can contain an application program, which can utilize an Application Programming Interface (API), or other object, software, firmware, and/or hardware, and which is suitable for use with a design framework in accordance with at least one general non-limiting embodiment.

It is also appreciated that an object, e.g., 620c, may be located on another computing device 610a, 610b, etc. or 620a, 620b, 620c, 620d, 620 e. Thus, while the depicted physical environment may show the connected devices as computers, such depiction is merely exemplary, the physical environment may alternatively be depicted or described as comprising various digital devices, such as PDAs, televisions, MP3 players, etc., any of which may utilize a variety of wired and wireless services, software objects such as interfaces, COM objects and the like.

There are a variety of systems, components, and network architectures that support distributed computing environments. For example, computing systems may be connected together by wired or wireless systems, by local area networks, or widely distributed networks. Currently, many networks are coupled to the internet, which provides the infrastructure for widely distributed computing and encompasses many different networks. Any infrastructure can be used for exemplary communications associated with the optimal algorithms and processes according to the present innovative application.

In a home networking environment, there are at least four different network transmission media, each of which supports unique protocols such as power line, data (both wireless and wired), audio (e.g., telephone), and entertainment media. Most home control devices, such as light switches and appliances, can be connected using power lines. Data services may enter the home as broadband (e.g., DSL or cable modem) and may be accessed within the home using wireless (e.g., HomeRF or 802.11A/B/C) or wired (e.g., HomePNA, Cat 5, Ethernet, or even power line) connections. Voice communications may enter the home as wired (e.g., Cat 3) or wireless (e.g., cell phones) and may be distributed within the home using Cat3 wiring. Entertainment media or other graphical data may enter the home via satellite or cable and is typically distributed in the home using coaxial cable. IEEE 1394 and DVI are also digital interconnects for clusters of media devices. All these network environments, as well as other network environments which may be or have been formed into protocol standards, may be interconnected to form a network, e.g. an intranet, which may be connected to the outside world by means of a wide area network, e.g. the internet. In short, there are a variety of different sources for data storage and transmission, such that any computing device of the present innovation application can share and transfer data in any existing manner, and none of the described ways in the embodiments is intended to be limiting.

The internet generally refers to a collection of networks and gateways that use the transmission control protocol/internet protocol (TCP/IP) suite of protocols well known in the art of computer networking. The internet can be described as a system of multiple, geographically dispersed, remote computer networks interconnected by computers executing networking protocols that allow users to interact and share information over the networks. Due to this widespread information sharing, remote networks, such as the internet, have been very commonly developed as an open system with which developers can design software applications for performing specialized operations or services, essentially without limitation.

Thus, the network infrastructure is capable of hosting a network topology, such as a client/server, peer-to-peer, or hybrid architecture. A "client" is a member of a class or group that uses the services of another class or group to which it is not related. Thus, in computing, a client is a process, i.e., a set of instructions or tasks, that requests a service provided by another program. The client process uses the requested service without having to "know" any working details about the other program or the service itself. In a client/server architecture, particularly a networked system, a client is often a computer used to access shared network resources provided by another computer (e.g., a server). In the illustration shown in FIG. 6, as an example, computers 620a, 620b, 620c, 620d, 620e, etc. can be thought of as clients and computers 610a, 610b, etc. can be thought of as servers where servers 610a, 610b, etc. retain data and the data is subsequently replicated in client computers 620a, 620b, 620c, 620d, 620e, etc., although any computer can be considered a client, a server, or both, depending on the circumstances. Any of these computing devices may process data or request services or tasks that may implicate optimal algorithms and processing in accordance with at least one general non-limiting embodiment.

A server is typically a remote computer system accessible over a remote or local network, such as the internet or wireless network infrastructure. Client processes may be active in a first computer system and server processes may be active in a second computer system, communicating with each other over a communications medium, thereby providing distributed functionality and allowing multiple clients to take advantage of the information-gathering capabilities of the server. Any software objects used in accordance with the optimization algorithms and processes of at least one general non-limiting embodiment can be distributed across multiple computing devices or objects.

The client and server communicate with each other using the functionality provided by the protocol layers. For example, the hypertext transfer protocol (HTTP) is a commonly used protocol that is used with the World Wide Web (WWW) or "Web". Typically, a computer network address, such as an Internet Protocol (IP) address, or other index, such as a Uniform Resource Locator (URL), may be used to identify the server or client computers to each other. The network address may be referred to as a URL address. Communication may be provided over a communication medium, for example a client and server may be coupled to each other via a TCP/IP connection to enable high performance communication.

Thus, fig. 6 illustrates an exemplary networked or distributed environment, with a server and client in communication via a network/bus, in which PAR back-off as described herein may be used. In more detail, in accordance with the subject innovation, a plurality of servers 610a, 610b, etc. are interconnected with a plurality of client or remote computing devices 620a, 620b, 620c, 620d, 620e, etc., such as laptop computers, handheld computers, thin clients, networked appliances or other devices (such as VCRs, TVs, ovens, lights, heaters, etc.) via a communication network/bus 640 (which may be a LAN, WAN, intranet, GSM network, internet, etc.). It is thus contemplated that the present innovation application can be applied to any computing device that is connected over a network to a device to which data is desired to be transferred.

For example, in a network environment in which the communications network/bus 640 is the Internet, the servers 610a, 610b, etc. can be Web servers with which the clients 620a, 620b, 620c, 620d, 620e, etc. communicate via any of a number of known protocols, such as HTTP. By way of distributed computing environment, servers 610a, 610b, etc. may also act as clients 620a, 620b, 620c, 620d, 620e, etc.

As noted, the communication may be wired or wireless or a combination thereof, where appropriate. Client devices 620a, 620b, 620c, 620d, 620e, etc. may or may not be capable of communicating via communications network/bus 640 and may have independent communications associated therewith. For example, in the case of a TV or VCR, there can or cannot be a networking scheme related to its control. Each of the client computers 620a, 620b, 620c, 620d, 620e, etc. and the server computers 610a, 610b, etc. may be equipped with a variety of application program modules or objects 5635a, 635b, 635c, etc. and have connections or access to various types of storage elements or objects through which files or data streams may be stored or to which a portion(s) of a file or data stream may be downloaded, transferred or migrated. Any one or more of the computers 610a, 610b, 620a, 620b, 620c, 620d, 620e, etc. may be responsible for maintaining and updating a database 630 or other storage unit, such as a database or memory 630 for storing data that is processed or maintained in accordance with at least one general non-limiting embodiment. Thus, the subject innovation can be employed in a computer network environment with client computers 620a, 620b, 620c, 620d, 620e, etc. that can access and interact with a computer network/bus 640 and server computers 610a, 610b, etc. that can interact with client computers 620a, 620b, 620c, 620d, 620e, etc. and other similar devices and databases 630.

Fig. 7 illustrates a wireless communication system 700 with multiple base stations 710 and multiple terminals 720 that can, for example, be employed in conjunction with one or more aspects of PAR back off as described herein. A base station is typically a fixed station that communicates with the terminals and may also be referred to as an access point, a node B, or some other terminology. Each base station 710 provides communication coverage for a particular geographic area, three geographic areas being shown, labeled 702a, 702b, and 702 c. The term "cell" can refer to a base station and/or its coverage area depending on the context in which the term is used. To provide system capacity, the base station coverage area may be partitioned into multiple smaller areas (e.g., three smaller areas per cell 702a in fig. 7) 704a, 704b, and 704 c. Each smaller area may be served by a respective Base Transceiver Subsystem (BTS). The term "sector" can refer to a BTS and/or its coverage area depending on the context in which the term is used. For a sectorized cell, the BTSs for all sectors of the cell are typically co-located within the base station for that cell. The transmission techniques described herein may be used for systems with sectorized cells as well as systems with unsectorized cells. For simplicity, in the following description, the term "base station" is used generically for a fixed station that serves a sector as well as a fixed station that serves a cell.

Terminals 720 are typically dispersed throughout the system, and each terminal may be fixed or mobile. A terminal may also be called a mobile station, a user equipment, or some other terminology. The terminal may be a wireless device, a cellular telephone, a Personal Digital Assistant (PDA), a wireless modem card, or the like. Each terminal 720 may communicate with 0, 1, or multiple base stations on the downlink and uplink at any given moment. The downlink (or forward link) refers to the communication link from the base stations to the terminals, and the uplink (or reverse link) refers to the communication link from the terminals to the base stations.

For a centralized architecture, a system controller 730 couples to base stations 710 and provides coordination and control for base stations 710. For a distributed architecture, the base stations 710 may communicate with each other as needed. Data transmission on the forward link occurs from one access point to one access terminal at or near the maximum data rate supported by the forward link and/or the communication system. Extra channel of forward link

A (e.g., control channel) may be transmitted from multiple access points to one access terminal. Reverse link data communication may occur from one access terminal to one or more access points.

Fig. 8 is an illustration of an ad hoc or unplanned/semi-planned wireless communication environment 800 in accordance with various aspects of PAR back off as described herein. System 800 can comprise one or more base stations 802 in one or more sectors that receive, transmit, replicate, etc., wireless communication signals to each other and/or to one or more mobile devices 804. As shown, each base station 802 can provide communication coverage for a particular geographic area, shown as three geographic areas, labeled 806a, 806b, 806c, and 806 d. Each base station 802 can comprise a transmitter chain and a receiver chain, each of which can in turn comprise a plurality of components associated with signal transmission and reception (e.g., processors, modulators, multiplexers, demodulators, demultiplexers, antennas, etc.), as will be appreciated by one skilled in the art. The mobile device 804 may be, for example, a cellular phone, a smart phone, a laptop, a handheld communication device, a handheld computing device, a satellite radio, a global positioning system, a PDA, and/or any other suitable device for communicating over the wireless network 800. The system 800 may be used in conjunction with various aspects described herein to enable successful PAR back off in one exemplary non-limiting embodiment.

Fig. 9 illustrates a methodology 900 that includes receiving a PAR back off value at 902. A power value, e.g., PA, is determined at 904 using the received PAR back off value. At 906, the PAR back off value is based at least in part on the modulation type. At 908, a rate for UL transmission is determined. At 910, PAR is based at least in part on modulation type and is more specific to QAM than QPSK.

When the various embodiments are implemented in software, firmware, middleware or microcode, program code or code segments, they may be stored in a machine-readable medium, such as a storage component. A code segment may represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. A code segment may be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted using any suitable means including memory sharing, message passing, token passing, network transmission, etc.

For a software implementation, the techniques described herein may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in memory units and executed by processors. The memory unit may be implemented within the processor or external to the processor, in which case it can be communicatively coupled to the processor via various means as is known in the art.

The mobile device may broadcast using a femto cell (femtocell) or a super-coverage cell (boomer cell). Femto cells, originally referred to as access point base stations, are scalable, multi-channel, two-way communication devices that extend a typical base station by consolidating all the major components of the telecommunications infrastructure. A typical example is a UMTS access point base station, which contains node B, RNC and a GSN, with only an ethernet or broadband connection (less commonly used AM/TDM) to the internet or intranet. VoIP applications allow such units to provide voice and data services in the same manner as ordinary base stations, but with the deployment simplicity of Wi-Fi access points. Other examples include CDMA-2000 and WiMAX solutions.

The main benefit of the access point base station is the simplicity of ultra-low cost, scalable deployment. Design studies have shown that access point base stations can be designed to extend from simple hot spot coverage to large scale deployments by transforming such units into full size base stations. It is attractive to cell operators that these devices can increase capacity and coverage simultaneously, while reducing Capex (capital expenditure) and Opex (operational expenditure).

An access point base station is a stand-alone unit that is typically deployed in hotspots, buildings, and even homes. Variations include adding Wi-Fi routers to allow Wi-Fi hotspots to operate as backhaul for cell hotspots, or vice versa. Femto cells are an alternative way to provide the benefits of fixed mobile convergence. The difference is that most FMC architectures require new (dual mode) handsets, while femtocell-based deployments will work with existing handsets.

As a result, the access point base station must work with handsets that conform to existing RAN technology. Reuse of existing RAN technology (and possibly reuse of existing frequency channels) can be problematic because the additional femtocell transmitters represent a significant source of interference, potentially resulting in a significant operational impact on existing deployments. This is one of the biggest problems that femto cells have to overcome if they want to succeed.

Access point base stations typically rely on the internet for connectivity, which can reduce the cost of deployment but introduce security risks that are not typically present in typical cellular systems. A super-coverage cell is a very large cell that may cover a state-sized area or larger.

Fig. 10 shows a methodology 1000 wherein a Channel Quality Indicator (CQI) from one antenna is utilized for power control as a reference signal at 1002. At 1004 at least one channel condition is obtained. At 1006, at least one channel condition is derived based at least in part on the plurality of broadband pilots. At 1008, at least one channel condition is derived based at least in part on the request channel. The decision as to what to get and how to get can be made through the use of the AI layer. Additionally, in other embodiments with or without a security layer, the cell may dynamically change the resulting operation based at least in part on AI decisions. The sensor may provide feedback to assist in the decision. For example, a sensor may determine network conditions at a particular time and change the amount and/or location of interference.

Fig. 11 illustrates a methodology 1100 in which a source node-B communicates with a mobile device at 1004. In one exemplary general non-limiting embodiment, method 1000 includes, at 1006, using a security layer. At 1008, at least one of a Power Allocation (PA), a peak-to-average ratio (PAR), and a Power Spectral Density (PSD) is dynamically changed or adjusted as described herein.

Because at least a portion of the communication between the device 1104 and the node B is wireless, a security layer 1106 is provided in one exemplary general non-limiting embodiment. The security layer 1106 may be used to cryptographically protect (e.g., encrypt) data and digitally sign data in order to enhance security and reduce unwanted, unintended, or malicious disclosure. In operation, the security component or layer 1106 can communicate data to and from the node B1102 and the mobile device 1104. A sensor 1110 is provided in one exemplary non-limiting embodiment.

The encryption component can be used to cryptographically protect data during transmission as well as upon storage. The encryption component uses an encryption algorithm to encode the data for security purposes. The algorithm is basically a formula for converting data into a password. Each algorithm performs a calculation using a string of bits called a "key". The larger the key (e.g., the more bits in the key), the larger the number of possible patterns that can be generated, thereby making it more difficult to break the code and decrypt the data content.

Most encryption algorithms use a block cipher method that encodes a fixed input block, typically from 64 to 128 bits in length. The decryption component may be used to convert the encrypted data back to its original form. In one aspect, the data may be encrypted using a public key when transferred to the storage device. At retrieval, the data may be decrypted with a private key that corresponds to the public key used for encryption.

The signature component can be used to digitally mark data and documents when sent and/or retrieved from device 1104. It will be appreciated that the digital signature or certificate ensures that the document is not altered, as would be the case if it were carried in an electronically sealed envelope. A "signature" is an encrypted digest (e.g., a one-way hash function) that is used to validate the authenticity of the data. Upon accessing the data, the recipient may decrypt the digest and also recalculate the digest based on the received file or data. If the digests match, the file is proven to be intact and not tampered with. In operation, digital certificates issued by certificate authorities are most often used to ensure the authenticity of digital signatures.

Further, the security layer 1106 can employ context awareness (e.g., context awareness components) to enhance security. For example, the context awareness component can be used to monitor and detect criteria related to data being sent to and requested from the device 1104. In operation, these environmental factors can be used to filter spam (spam), control retrieval (e.g., access to highly sensitive data from a public network), and the like. It will be appreciated that in various aspects, the context awareness component can employ logic that manages the transfer and/or retrieval of data in accordance with external criteria and factors. The context awareness component can be used with an Artificial Intelligence (AI) layer.

The AI layer or component can be utilized to help infer and/or determine when, where, how to dynamically change the security level and/or the amount of power value change. Such inference enables the construction of new events or actions from a set of observed events and/or stored event data, whether or not the events are correlated in close temporal proximity, and whether the events and data come from one or several event and data sources.

The AI component can also employ any of a number of suitable AI-based schemes in conjunction with various schemes that facilitate the innovative applications described herein. Classification can employ a probabilistic and/or statistical-based analysis (e.g., factoring into the analysis utilities and costs) to prognose or infer an action that a user desires to be automatically performed. The AI layer may be used in conjunction with the security layer to infer changes in the data being transmitted and to suggest what security level the security layer uses.

For example, a classifier of a Support Vector Machine (SVM) may be used. Other classification schemes include bayesian networks, decision trees, and probabilistic classification models providing different patterns of independence can be used. Classification as used herein also is inclusive of statistical regression that is utilized to develop models of interest.

Additionally, the sensor 1110 may be used in conjunction with the security layer 1106. Still further, a human authentication factor may be used to enhance the security application sensor 1110. For example, biometrics (e.g., fingerprints, retinal patterns, facial recognition, DNA sequences, handwriting analysis, voice recognition) may be used to enhance authentication to control access to a repository. It will be appreciated that embodiments may use testing of a variety of factors in verifying the identity of a user.

The sensors 1110 may also be used to provide general non-human measurement data, such as electromagnetic field condition data or predicted weather data, etc., to the security layer 1106. For example, any conceivable condition may be sensed and the security level adjusted or determined in response to the sensed condition.

Fig. 12 illustrates an environment 1200 in which a node B, such as a source node 1202, communicates with a mobile device at 1204. In one exemplary general non-limiting embodiment, the method 1200 includes using an optimizer at 1206. Optimizer 1206 is used to optimize communications between node B1202 and device 1204. Optimizer 1206 optimizes or augments communication between node B1202 and device 1204 by receiving security information from security layer 1208. For example, when security layer 1208 notifies optimizer 1206 that they are both in a secure environment, optimizer 1206 weighs this information against other information and may instruct security layer 1208 to make all transmissions unnecessary for secure processing to achieve the highest speed. Additionally, a feedback layer or component 1210 can provide feedback regarding lost data packets or other information to provide feedback to the optimizer 1206. This feedback on lost packets may be weighed against the expected level of security to allow for data delivery with lower security but higher throughput, if desired. Additionally, the optimizer 1206 may maintain a record of interference and different PAR back off schemes and adaptively select the best scheme under current conditions.

As mentioned, the present inventive arrangements are applicable to any device that wishes to communicate data to, for example, a mobile device. It should be understood, therefore, that handheld, portable and various other computing devices and computing objects are contemplated for use in connection with the present application, i.e., anywhere that a device may transmit data or receive, process or store data. Thus, the below general purpose remote computer described below in FIG. 11 is but one example, and the present application may be implemented with any client having network/bus interoperability and interaction. Thus, the present application may be implemented in a networked hosted service environment in which very little or minimal client resources are implicated, e.g., a networked environment in which the client device serves merely as an interface to the network/bus, such as an object disposed in a device.

Although not required, at least one general non-limiting embodiment can be implemented in part by an operating system for use by a developer of services for a device or object, and/or included within application software that operates in conjunction with the components of at least one general non-limiting embodiment. Software may be described in the general context of computer-executable instructions, such as program modules, executed by one or more computers, such as client workstations, servers or other devices. Those skilled in the art will appreciate that the present application may be practiced with other computer system architectures and protocols.

Fig. 13, 14 and 15 provide PAR simulation results for LFDM and OFDM using the modulation orders specified in table 1 in graphs 1300, 1400 and 1500, respectively. These results show that there is about a 1dB PAR difference between 64QAM and QPSK or between 16QAM and QPSK at the 99.9% PAR point of SC-FDM. The PAR difference between 64QAM and 16QAM is quite small. For localized OFDM, the difference in PAR is small for all modulations. This is a noticeable PAR reduction when comparing LFDM to OFDM. The difference is about 2.5dB for QPSK and 1.8dB for 16QAM and 64 QAM. Fig. 13 shows PAR of LFDM using 16QAM and QPSK, fig. 14 shows PAR of LFDM using 64QAM and QPSK, and fig. 15 shows PAR of LFDM using 64QAM and 16 QAM. For MIMO transmission with PARC, the PAR difference between different streams may be greater than 1 dB. For MIMO transmission with antenna permutation such as VAP, the PAR is between the PAR of the two modulations and biased towards the PAR of the higher modulation order. With higher order modulation being a type of digital modulation typically having an order of 4 or more. Example (c): quadrature Phase Shift Keying (QPSK), m-ary quadrature amplitude modulation (m-QAM), etc.

From the above description, when the UE feeds back to the node B a Δ PSD for scheduling a specific rate, both the UE and the node B must clearly take into account a specific PAR back off. This applies not only to MIMO operation but also to SIMO or SISO operation. For example, if the Δ PSD reported back by the UE exhibits PAR back-off on QPSK transmission, the node B must know the exact back-off exhibited. If the node B schedules a Modulation Coding Scheme (MCS) using 16QAM without PA backoff adjustment, the scheduled rate is higher than what the UE can actually support. This can result in unnecessary packet retransmissions and loss of throughput.

In order to properly operate the system, it must be well defined in standard specifications: for MIMO and SIMO operations, what PAR back off is exhibited when Δ PSD is fed back from the UE to the node B. One such definition would be that the UE should feed back a Δ PSD that exhibits QPSK PAR back off or 16QAM PAR back off. The scheduler selects the MCS based on the Δ PSD. If the modulation order is different from the modulation order used, the PAR difference needs to be taken into account and a different MCS may be selected instead. The PAR differences for the various modulations are indicated above for SIMO and MIMO operation.

Described herein is the impact of PAR back off values in various MIMO schemes when LFDM is used for UL transmission. When no permutation is applied to the MIMO layers (e.g., PARC), there is a considerable PAR difference for different modulation orders. If a permutation of the symbol level layers is used, such as selective virtual antenna permutation (S-VAP), the PAR of each layer is close to the average of the PAR of the layers before the permutation.

Also, in one aspect, for SIMO and MIMO operations, it must be specified in the standard: which type of PAR back off is presented when the UE reports the Δ PSD back. Based on this information, the node B can apply different PAR back-offs appropriately and select the correct rate for UL transmission.

What has been described above includes examples of one or more aspects. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned aspects, but one of ordinary skill in the art may recognize that many further combinations and permutations of various aspects are possible. Accordingly, the described aspects are intended to embrace all such alterations, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim.

Claims (24)

1. A method for a wireless communication system, the method comprising:

receiving or storing a PAR back off value; and

a transmit power value is determined using the received PAR back off value.

2. The method of claim 1, wherein the PAR back off value is based at least in part on a modulation type.

3. The method of claim 1, further comprising determining a rate of UL transmission.

4. The method of claim 1, wherein the PAR back off value is based at least in part on a modulation type, and a PAR back off value for a higher order QAM modulation is greater than a PAR back off value for a QPSK modulation.

5. The method of claim 1, wherein the PAR back off value is based at least in part on a modulation type and is greater for 16QAM modulation than for QPSK modulation.

6. The method of claim 1, wherein the PAR back off value is based at least in part on a modulation type and is greater for 64QAM modulation than for QPSK modulation.

7. The method of claim 1, wherein a transmission power of each of the plurality of MIMO streams and a supportable rate of a different stream further depend on a unitary transform.

8. The method of claim 7, wherein the unitary transformation is a virtual antenna mapping.

9. The method of claim 7, wherein the unitary transform is an antenna permutation matrix.

10. The method of claim 7, wherein the unitary transformation is a MIMO precoding matrix.

11. The method of claim 1, further comprising: power control is used for Channel Quality Indicator (CQI) from one antenna as a reference signal.

12. The method of claim 11, further comprising: at least one channel condition is obtained.

13. The method of claim 11, further comprising: at least one channel condition is derived based at least in part on the request channel.

14. The method of claim 11, further comprising: at least one channel condition is derived based at least in part on the plurality of broadband pilots.

15. The method of claim 1, further comprising: the Δ PSD is reported to the node B.

16. The method of claim 15, further comprising calculating at least one data rate for a user not affected by inter-user interference based on an effective signal-to-noise ratio (SNR) after SIC.

17. The method of claim 15, further comprising calculating at least one data rate for a user not affected by inter-user interference based on an effective signal-to-noise ratio (SNR) after SIC.

18. A method for a wireless communication system, the method comprising:

sending or storing a PAR back off value; and

reporting a Δ PSD to a node B taking into account the PAR back off value.

19. An apparatus operable in a wireless communication system, the apparatus comprising:

means for receiving or storing a PAR back off value and receiving a Δ PSD;

means for determining a power value using the PAR back off value; and

means for determining a rate of UL transmissions.

20. A machine-readable medium comprising instructions that, when executed by a machine, cause the machine to:

receiving or storing a PAR back off value and receiving a Δ PSD;

determining a power value using the PAR back off value; and

the rate of UL transmission is determined.

21. An apparatus operable in a wireless communication system, the apparatus comprising:

a processor configured to receive or store a PAR back off value and receive a Δ PSD and to determine a power value using the received PAR back off value; and

a memory coupled to the processor for storing data.

22. The apparatus of claim 21, wherein the processor is configured to: a PAR back off value is received or stored, the PAR back off value based at least in part on a modulation type.

23. The apparatus of claim 21, wherein the processor is configured to: the rate of UL transmission is determined.

24. The apparatus of claim 21, wherein the processor is configured to: a PAR back off value is received or stored that is based at least in part on the modulation type and that is greater for higher order QAM modulations than for QPSK modulations.