HK1151924A - Tdd operation in wireless communication systems - Google Patents

Description

TDD operation in wireless communication system

Cross Reference to Related Applications

This application claims priority to U.S. provisional patent application No.61/019,571, entitled FRAME STRUCTURE OPERATION IN communications systems, filed on 7/1/2008, which is incorporated herein by reference IN its entirety.

Technical Field

The following description relates generally to wireless communication systems and, more particularly, to a frame structure protocol that facilitates efficient communication.

Background

Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems including E-UTRA, and Orthogonal Frequency Division Multiple Access (OFDMA) systems.

An Orthogonal Frequency Division Multiplexing (OFDM) communication system efficiently partitions an overall system bandwidth into a plurality of N_FMultiple) subcarriers, which may also be referred to as frequency subchannels, tones, bins, or the like. For an OFDM system, the data to be transmitted (i.e.,information bits) are first encoded in a particular coding scheme to generate coded bits, the coded bits are further grouped into multi-bit symbols, and the multi-bit symbols are then mapped to modulation symbols. Each modulation symbol corresponds to a point in a signal constellation defined by a particular modulation scheme (e.g., M-PSK or M-QAM) used for data transmission. The modulation symbols may be at N at each time interval that may depend on the bandwidth of each frequency subcarrier_FTransmitting on each of the frequency subcarriers. Thus, OFDM may be used to reduce inter-symbol interference (ISI) caused by frequency selective fading, which is characterized by different amounts of attenuation over the system bandwidth.

In general, a wireless multiple-access communication system is capable of supporting communication for multiple wireless terminals simultaneously, with the multiple wireless terminals communicating 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. Such communication links may be established by single-in single-out, multiple-in single-out, or multiple-in multiple-out (MIMO) systems.

A MIMO system uses multiple (NT) transmit antennas and multiple (NR) receive antennas for data transmission. The MIMO channel formed by the NT transmit and NR receive antennas may be decomposed into NS independent channels, also referred to as spatial channels, where N is_S≤min{N_T，N_R}. In general, each of the NS independent channels corresponds to a dimension. MIMO systems can 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 also support Time Division Duplex (TDD) and Frequency Division Duplex (FDD) systems. In a TDD system, the forward and reverse link transmissions are in the same frequency region, so the reciprocity principle allows the estimation of the forward link channel from the reverse link channel. This enables the access point to extract transmit beamforming gain on the forward link when multiple antennas are available at the access point.

One common application in wireless systems is for uplink and downlink communications between a base station and a wireless device. In these cases, no overlap between the signals is desired when one component is transmitting and the other is receiving. In other words, when one component should receive and another component should transmit, the components should not transmit simultaneously in the downlink or uplink. Existing protocol systems can result in such overlap, which is undesirable as communication technology evolves.

Disclosure of Invention

The following presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview nor is it intended to identify key/critical elements or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

Systems and methods are disclosed for utilizing frame structure protocol enhancements for optimizing the use of uplink and downlink channels in a wireless communication system. In one example, such protocol enhancements may be used with Long Term Evolution (LTE) systems that remain compatible with existing time division synchronous code division multiple access (TD-SCDMA) systems in an efficient manner. Guard periods are provided within the transmission intervals of the radio frame structure to facilitate efficient switching between downlink and uplink channels. The guard period is used to prevent or mitigate overlap between transmitting and receiving wireless devices (e.g., prevent two communicating components from transmitting simultaneously). The time period may be automatically configured or manually configured by a user to allow efficient deployment of a given wireless cell while mitigating transmission time period overlap during handover between downlink and uplink intervals. In one example, the guard period may be allocated to the downlink portion of the transmission interval, and the uplink portion of the interval and the additional guard period may be inserted between the respective uplink and downlink portions. In addition, an optimal uplink and downlink ratio can be specified and configured to improve the efficiency of wireless communication.

To the accomplishment of the foregoing and related ends, certain illustrative aspects are described herein in connection with the following description and the annexed drawings. These aspects are indicative, however, of but a few of the various ways in which the principles of the claimed subject matter may be employed and the claimed subject matter is intended to include all such aspects and their equivalents. Other advantages and novel features of the invention may become apparent from the following detailed description of the invention when considered in conjunction with the drawings.

Drawings

Fig. 1 is a high-level block diagram of a system that uses guard periods to facilitate switching between uplink and downlink portions in a wireless broadcast.

Fig. 2 illustrates a high level diagram of a transmission interval using a guard period to mitigate frequency overlap between uplink and downlink communications.

Fig. 3 shows a detailed diagram of an exemplary transmission interval using a guard period to mitigate frequency overlap between uplink and downlink communications.

Fig. 4 shows a detailed diagram of an exemplary acquisition time period using a guard period to mitigate frequency overlap between uplink and downlink communications.

Fig. 5 illustrates a wireless communication method that utilizes a frame structure protocol to facilitate switching between uplink and downlink communications.

Fig. 6 illustrates exemplary logic modules for a frame structure protocol.

Fig. 7 illustrates exemplary logic modules for another frame structure protocol.

Fig. 8 illustrates an exemplary communication device using a frame structure protocol.

Fig. 9 shows a multiple access wireless communication system.

Fig. 10 and 11 illustrate exemplary communication systems that may use a frame structure protocol.

Detailed Description

The present invention provides a system and method to facilitate switching between downlink and uplink portions of wireless communications. In one aspect, a method provides a radio frame protocol. The method includes transmitting a transmission gap that facilitates switching between a downlink portion and an uplink portion of a wireless communication channel. The method utilizes one or more guard periods during the transmission interval to mitigate overlap of transmit frequencies between downlink and uplink portions of the wireless communication channel.

Referring to fig. 1, a system 100 employs guard periods to facilitate switching between uplink and downlink portions of a wireless network 110. System 100 includes a base station 120 (also referred to as an evolved node B or eNB), which is an entity capable of communicating with a second device 130 (or devices) over wireless network 110. For example, each device 130 may be an access terminal (also referred to as a terminal, user equipment, or mobile device). Each of the components 120 and 130 includes a frame protocol component 140 and 150, respectively, wherein the protocol components are provided to improve the efficiency of communications over the network 110. As shown, base station 120 transmits data to device 130 over downlink 160 and receives data from device 130 over uplink 170. Such designation of uplink and downlink is arbitrary, and the device 130 may also transmit data via the downlink and receive data via the uplink channel. It should be noted that although two components 120 and 130 are shown, more than two components may be used in network 110, wherein these additional components may also be modified to accommodate the frame structure protocol described herein.

As shown, one or more guard periods 180 are used to optimize the use of uplink and downlink channels 160 and 170 in the wireless communication system 100. In one example, the frame protocol components 140 and 150 may be used with a Long Term Evolution (LTE) system that also remains compatible with existing time division synchronous code division multiple access (TD-SCDMA) systems in an efficient manner. The guard period 180 is in the transmission interval of the radio frame structure (described in detail below) to facilitate efficient switching between the downlink and uplink channels 160 and 170. The guard period 180 is used to prevent or mitigate overlap between transmitting and receiving wireless devices (e.g., prevent the two communication components 120 and 130 from transmitting at approximately the same time). This time period 180 may be automatically configured or manually configured by a user to allow efficient deployment of a given wireless cell or network 110 while mitigating transmission time period overlap during a handover between downlink and uplink intervals. In one example, the guard period 180 can be allocated to a downlink portion of a transmission interval, an uplink portion of the interval, and additional guard periods inserted between the respective uplink and downlink portions. In addition, an optimal uplink and downlink ratio can be specified and configured to improve the efficiency of wireless communication.

In general, the various aspects supported by frame protocol components 140 and 150 are described in detail below in conjunction with FIGS. 2-4. This includes systems and methods that provide radio frame protocols 140 and 150 that convey transmission intervals that facilitate switching between a downlink portion 160 and an uplink portion 170 of a wireless communication channel. The method utilizes one or more guard periods during the transmission interval to mitigate overlap of transmit frequencies between downlink and uplink portions of the wireless communication channel. Guard period 180 includes a configurable time reservation including at least one downlink pilot transmission structure (DwPTS). Such a guard period 180 also includes at least one uplink pilot transmission structure (UpPTS) and may be configured, for example, as a total period of approximately one millisecond.

The guard period 180 may be configured to repeat with a period of approximately five or ten milliseconds. For example, the time period 180 may be configured as two specific time slots associated with eight traffic slots during an approximately ten millisecond interval. For example, this includes configuring the ratio of downlink (d) to uplink (u) (d: u), including 4: 4, 5: 3, 6: 2, or 3: 5. In another aspect, for example, the guard period 180 can be configured as one particular time slot associated with nine traffic slots during an approximately ten millisecond interval. In this example, the ratio of downlink (d) to uplink (u) (d: u) may comprise 5: 4, 6: 3, 7: 2, or 4: 5, for example.

In another aspect, the transmission interval (described in detail below) is approximately five milliseconds and may include at least five subframes and at least eight traffic slots. For example, the slots may include at least one of a Packet Data Control Channel (PDCCH) or a Physical Broadcast Channel (PBCH) and a Primary Synchronization Signal (PSS) or a Secondary Synchronization Signal (SSS). These slots may include one or more resource blocks for a portion of eight traffic slots. As previously mentioned, these transmission intervals, specific slots, traffic slots, subframes, etc., will be described in detail below with reference to fig. 2-4.

It should be noted that the system 100 may be used for access terminals or mobile devices and may be, for example, a module such as an SD card, a network card, a wireless network card, etc., a computer (including notebook, desktop, personal digital assistant PDA), a mobile phone, a smart phone, or any other available terminal that can be used to access a network. The terminal accesses the network through an access component (not shown). In one example, the connection between the terminal and the access component, which can be a base station, and the mobile device can be a wireless terminal, can be wireless in nature. For example, the terminals and base stations may communicate using any suitable wireless protocol, including but not limited to Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiplexing (OFDM), FLASH OFDM, Orthogonal Frequency Division Multiple Access (OFDMA), or other suitable protocols.

The access component may be an access node associated with a wired network or a wireless network. For this purpose, the access component can be, for example, a router, a switch, etc. The access component may include one or more interfaces, such as a communication module, for communicating with other network nodes. Further, the access component may be a base station (or wireless access point) in a cellular-type network, wherein the base station (or wireless access point) is used to provide wireless coverage to a plurality of users. Such a base station (or wireless access point) may be configured to provide a continuous coverage area for one or more cellular telephones and/or other wireless terminals.

Referring to fig. 2, fig. 2 is an exemplary diagram 200 of a transmission interval using guard periods to mitigate frequency overlap between uplink and downlink communications. For simplicity, a number of acronyms are used, and a detailed list of acronym definitions can be found towards the end of the specification. Generally, eight traffic slots and three specific slots are configured during the exemplary transmission interval 210. The traffic slots may include similar OFDM designations as in Frequency Division Duplex (FDD). The specific time slot includes a downlink pilot transmission structure (DwPTS)220, a Guard Period (GP)230, and an uplink pilot transmission structure (UpPTS), wherein a combination of 220, 230, and 240 may be configured to about 1 millisecond (ms). Thus, the respective lengths are configurable, the Primary Synchronization (PSC) typically being the first symbol of the DwPTS 220. The Secondary Synchronization (SSC) is typically the last symbol of subframe 0 described below. The UpPTS 240 and DwPTS 220 may be used to efficiently utilize resources, and the guard period 230 is used to help absorb DL- > UL and UL- > DL handover between communication devices.

Generally, subframe zero (SF0) precedes the downlink portion and the time slot after UpPTS includes the uplink portion. Typically, there is one DL- > UL handover at the 10ms boundary, but it may also be configured that more than one handover occurs. In one aspect, the eNB adjusts the time contained within the guard period 230. In another aspect, a Data Transmitter (DTX) uses 1 OFDM symbol for a switching time of approximately ≧ 30 ms. The first particular slot at 220 may include a downlink PSC (at 1.25MHz) in the first OFDM symbol. This also allows resource utilization allocation.

Some attributes of the DwPTS include 1.4MHz operation using the first symbol PSC. Other symbols include PDSCH > 1.4MHz, with the first symbol: 1.25MHz PSC, residual bandwidth: the PDSCH, D-BCH, is used to solve other time problems. Other aspects include utilizing Resource Blocks (RBs) in the DwPTS. This includes a separate PDCCH, possibly with a maximum interval of 1, which may alleviate the need for PHICH or PCFICH. The SF0 resource block may be extended to DwPTS.

For UpPTS, the physical layer random access burst may have a short burst: for example, the first 25ms (768Ts) before UpPTS. The normal/extended time period may include: for example, the start of the UL subframe start is aligned, where up to 16 allowed preamble sequences may be used. The burst may use the remaining resources for PUSCH/PUCCH, if needed. One option includes allocating only the transmit PUCCH to the user, thereby providing better tolerance to RACH changes. In another aspect, UpPTS may be eliminated when RACH in a subframe is provided after UpPTS and SRS as in FDD protocol may be used. The UpPTS may also be used for SRS and a subframe following the UpPTS is used for RACH. This may include TDM, IFDM and LFDM, for example. In another aspect, the UL/DL configuration may be restricted (or extended) for testing, delay, feedback, HARQ processing, asymmetry issues, UL control, transition frequencies, frequency hopping, and UL overhead, among others.

For HARQ, some processing may be considered, including retransmission delay, receiver buffering requirements, transmitter/receiver complexity to meet the timeline. This includes providing manageable configuration complexity, processing power, ACK multiplexing on the UL including asymmetry. Timing may include 3ms processing time for the UE and eNB, supportable cell size, and DTX/DRX considerations, where synchronous operation may reduce overhead. UL power control may include interference management, sounding reference signals with SRS support selected at the eNB. The PUCCH structure includes orthogonal cover (orthogonal cover) for modulation, orthogonal cover for demodulation of RS, and mapping to physical resources.

Referring to fig. 3, fig. 3 illustrates an exemplary detailed transmission interval 300 that uses guard periods to mitigate frequency overlap between uplink and downlink communications. As shown, subframe zero 310 precedes DwPTS period 320, guard period 330, UpPTS period 340, and subsequent subframe two 350. The DwPTS time period includes a control portion 360 and a data portion 370 and follows a Secondary Synchronization Signal (SSS)390 before a Primary Synchronization Signal (PSS) 380. Some exemplary parameters include DwPTS length: for example, normal CP: 3-14 OFDM symbols, subframe 1: max 12, extended CP: 3-12 OFDM symbols, and subframe 1: maximum 10. The PSS is transmitted on the third OFDM symbol subframes 1 and 6. PDCCH interval: e.g., 1 or 2 OFDM symbols. The data transmitted after the control region may be similar to DL subframes. The data PRBs generally do not include a PSS. The cell-specific RS pattern is similar to other DL subframes.

The guard period 330 may be configured to support a configuration to support, for example, a 100km cell radius, where normal CP: 1-10 OFDM symbols, extended CP: 1-8 OFDM symbols. For example, the guard period may include 1-2 OFDM symbols. The duration of the UpPTS 340 is typically 1 or 2 OFDM symbols, where 1 symbol is used for SRS only and two symbols are used for SRS on 1 or two symbols with short RACH.

Referring to fig. 4, an exemplary acquisition time period 400 is shown that uses a guard period to mitigate frequency overlap between uplink and downlink communications. As shown, a typical time period 410 may be about 10 milliseconds and include 10 subframes (0 to 9). A subframe may be decomposed into a traffic slot and a specific slot, wherein the specific slot provides the above-described guard period. The guard period is shown at 420 in subframe 1 and at 430 in subframe 6. The traffic slots may include normal cyclic prefixes at 440 and 442 and/or extended prefixes at 450 and 452. The prefix may include, for example, PDCCH (denoted as C in the figure), PSS (denoted as P in the figure), SS1 (denoted as S1 in the figure), SS2 (denoted as S2 in the figure), and PBCH (denoted as B in the figure). Resource blocks may also be provided.

Referring to fig. 5, a wireless communication method 500 is shown. While, for purposes of simplicity of explanation, the methodologies (and other methodologies described herein) 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 one or more embodiments, 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 utilized to implement a methodology in accordance with the claimed subject matter.

Proceeding to step 510, the transmission interval may be defined as approximately five milliseconds as previously described. Typically, two transmission intervals comprise an acquisition period of about ten milliseconds. At step 520, a guard period is associated with the transmission interval. As previously described, these may include DwPTS and UpPTS and a Guard Period (GP) in between. As described above, the guard period may be configured to repeat with a period of approximately five or ten milliseconds. For example, the time periods (DwPTS, GP, UpPTS) may be configured as two specific time slots associated with eight traffic time slots during an approximately ten millisecond interval. This includes configuring the ratio (d: u) of downlink (d) to uplink (u), including, for example, 4: 4, 5: 3, 6: 2, or 3: 5. In another aspect, for example, the guard period may be configured as one particular time slot associated with nine traffic slots during an approximately ten millisecond interval. In this example, the ratio (d: u) of downlink (d) to uplink (u) may include, for example, 5: 4, 6: 3, 7: 2, or 4: 5. At step 530, the guard period is configured to be modified to accommodate the particular application at hand. For example, if fewer devices are involved, a shorter guard period may be configured. Such time periods may be manually configured at the base station or UE and/or automatically configured according to each detected application or situation. In step 540, the guard periods are used to mitigate frequency overlap during the switching periods between downlink and uplink channels of the various wireless communication components (e.g., base station and UE).

The techniques described herein may be implemented by various means. For example, these techniques may be implemented in hardware, software, or a combination thereof. In 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 or other electronic units designed to perform the functions described herein, or various combinations thereof. For a software implementation, the functions 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.

Referring to fig. 6 and 7, a system relating to wireless signal processing is provided. The system is represented as a series of interrelated functional blocks, which can represent functions implemented by a processor, software, hardware, firmware, or a suitable combination thereof.

Referring to fig. 6, a wireless communication system 600 is provided. The system 600 includes a logical module 602 for generating a transmission interval that includes one or more particular time periods for mitigating frequency overlap between downlink and uplink portions of wireless communication. The system 600 also includes a logic module 604 for configuring the particular time period and a logic module 606 for configuring a ratio between downlink and uplink portions of the wireless communication.

Referring to fig. 7, a wireless communication system 700 is provided. The system 700 includes a logical module 702 for receiving a transmission interval that includes one or more particular time periods for facilitating switching between downlink and uplink portions of wireless communication. System 700 also includes a logic module 704 for configuring a particular time period and a logic module 706 for configuring a ratio between downlink and uplink portions of the wireless communication.

Fig. 8 shows a communication device 800, which may be, for example, a wireless communication device such as a wireless terminal. Additionally or alternatively, communications device 800 may reside within a wired network. The communications apparatus 800 can include a memory 802, and the memory 802 can retain instructions for performing signal analysis in a wireless communication terminal. Further, the communications apparatus 800 can include a processor 804, where the processor 804 can execute instructions within the memory 802 and/or instructions received from another network device, where the instructions can relate to configuring or operating the communications apparatus 800 or a related communications apparatus.

Referring to fig. 9, fig. 9 illustrates a multiple access wireless communication system 900. The multiple access wireless communication system 900 includes a plurality of cells including cells 902, 904, and 906. In one aspect of system 900, cells 902, 904, and 906 can comprise node Bs comprising a plurality of sectors. Multiple sectors may be formed by groups of antennas, with each antenna being responsible for communication with UEs in a portion of the cell. For example, in cell 902, antenna groups 912, 914, and 916 may each correspond to a different sector. In cell 904, antenna groups 918, 920, and 922 each correspond to a different sector. In cell 906, antenna groups 924, 926, and 928 each correspond to a different sector. Cells 902, 904, and 906 may include several wireless communication devices, such as user equipment or UEs, which may communicate with one or more sectors of each cell 902, 904, and 906. For example, UEs 930 and 932 may communicate with node B942, UEs 934 and 936 may communicate with node B944, and UEs 938 and 940 may communicate with node B946.

Referring to fig. 10, fig. 10 illustrates a multiple access wireless communication system in accordance with an aspect. An access point 1000(AP) includes multiple antenna groups, one including 1004 and 1006, another including 1008 and 1010, and an additional including 1012 and 1014. In fig. 10, only two antennas are shown for each antenna group, but more or fewer antennas may be utilized for each antenna group. Access terminal 1016(AT) is in communication with antennas 1012 and 1014, where antennas 1012 and 1014 transmit information to access terminal 1016 over forward link 1020 and receive information from access terminal 1016 over reverse link 1018. Access terminal 1022 is in communication with antennas 1006 and 1008, where antennas 1006 and 1008 transmit information to access terminal 1022 over forward link 1026 and receive information from access terminal 1022 over reverse link 1024. In a FDD system, communication links 1018, 1020, 1024 and 1026 may use different communication frequencies. For example, forward link 1020 may use a different frequency than reverse link 1018.

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. Antenna groups each are designed to communicate to access terminals in a sector, of the areas covered by access point 1000. In communication over forward links 1020 and 1026, the transmitting antennas of access point 1000 utilize beamforming in order to improve the signal-to-noise ratio of the forward links for the different access terminals 1016 and 1024. Likewise, an access point using beamforming to transmit to randomly dispersed access terminals in a coverage area 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 other terminology.

Referring to fig. 11, a system 1100 illustrates a transmitter system 210 (also referred to as an access point) and a receiver system 1150 (also referred to as an access terminal) in a MIMO system 1100. At the transmitter system 1110, traffic data for a number of data streams is provided from a data source 1112 to a Transmit (TX) data processor 1114. Each data stream is transmitted over a respective transmit antenna. TX data processor 1114 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 pattern that is processed in a known manner and may be 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., BPSK, QPSK, 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 1130.

The modulation symbols for all data streams are then provided to a TX MIMO processor 1120, and the modulation symbols may be further processed by the TX MIMO processor 1120 (e.g., for OFDM). TX MIMO processor 1120 then provides NT modulation symbol streams to NT transmitters (TMTR)1122a through 1122 t. In some embodiments, TX MIMO processor 1120 applies beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.

Each transmitter 1122 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. NT modulated signals from transmitters 1122a through 1122t are then transmitted from NT antennas 1124a through 1124t, respectively.

At receiver system 1150, the transmitted modulated signals are received by NR antennas 1152a through 1152r and the received signal from each antenna 1152 is provided to a respective receiver (RCVR)1154a through 1154 r. Each receiver 1154 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.

An RX data processor 1160 then receives and processes the NR received symbol streams from NR receivers 1154 based on a particular receiver processing technique to provide NT "detected" symbol streams. The RX data processor 1160 then demodulates, deinterleaves, and decodes each detected symbol stream to recover the traffic data for the data stream. The processing by RX data processor 1160 is complementary to that performed by TX MIMO processor 1120 and TX data processor 1114 at transmitter system 1110.

A processor 1170 periodically determines which pre-coding matrix to use (described in detail below). Processor 1170 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 1138 (TX data processor 1138 also receives traffic data for a number of data streams from a data source 1136), modulated by a modulator 1180, conditioned by transmitters 1154a through 1154r, and transmitted back to transmitter system 1110.

At transmitter system 1110, the modulated signals from receiver system 1150 are received by antennas 1124, conditioned by receivers 1122, demodulated by a demodulator 1140, and processed by a RX data processor 1142 to extract the reserve link message transmitted by receiver system 1150. Processor 1130 then determines which pre-coding matrix to use for determining the beamforming weights then processes the extracted message.

In one aspect, logical channels are divided into control channels and traffic channels. The logical control channels include: a Broadcast Control Channel (BCCH), which is a DL channel for broadcasting system control information; a Paging Control Channel (PCCH), which is a DL channel transmitting paging information; multicast Control Channel (MCCH), which is a point-to-multipoint DL channel used for transmitting Multimedia Broadcast and Multicast Service (MBMS) scheduling and control information for one or more MTCHs. Generally, this channel is only used by UEs receiving MBMS (note: past MCCH + MSCH) after 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. Logical traffic channels include a Dedicated Traffic Channel (DTCH), which is a point-to-point bi-directional channel dedicated to one UE for the transmission of user information. Similarly, a Multicast Traffic Channel (MTCH) is a point-to-multipoint DL channel for transmitting traffic data.

The transport channels are divided into 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 may 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)

Response 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)

Response channel (ACKCH)

Antenna Subset Indicator Channel (ASICH)

Shared request channel (SREQCH)

UL physical shared data channel (UL-PSDCH)

Broadband pilot channel (BPICH)

Other terms include: 3G third generation; 3GPP third generation partnership project; ACLR adjacent channel leakage ratio; ACPR adjacent channel power ratio; ACS critical channel selectivity; ADS advanced design system; AMC adaptive modulation and coding; a-MPR additional maximum power reduction; ARQ automatic repeat request; BCCH broadcast control channel; a BTS base transceiver station; CDD cyclic delay diversity; CCDF complementary cumulative distribution function; CDMA code division multiple access; a CFI control format indicator; Co-MIMO cooperative MIMO; a CP cyclic prefix; a CPICH common pilot channel; a CPRI common public radio interface; a CQI channel quality indicator; CRC cyclic redundancy check; a DCI downlink control indicator; DFT discrete Fourier transform; DFT-SOFDM discrete Fourier transform spread OFDM; DL downlink (base station to user transmission); a DL-SCH downlink shared channel; D-PHY 500Mbps physical layer; DSP digital signal processing; a DT development kit; analyzing a DVSA digital vector signal; EDA electronic design automation; an E-DCH enhanced dedicated channel; E-UTRAN evolution UMTS terrestrial radio access network; an eMBMS evolved multimedia broadcast multicast service; an eNB evolved node B; an EPC evolved packet core network; EPRE energy per resource element; ETSI european telecommunications standards institute; E-UTRA evolved UTRA; UTRAN of E-UTRAN evolution; EVM error vector magnitude; and FDD frequency division duplexing.

Still other terms include: FFT fast Fourier transform; FRC fixed reference channel; FS 11 type frame structure; FS 22 type frame structure; GSM global system for mobile communications; HARQ hybrid automatic repeat request; HDL hardware description language; a HI HARQ indicator; HSDPA high speed downlink packet access; HSPA high-speed packet access; HSUPA high speed uplink packet access; inverse FFT of IFFT; an IOT interoperability test; IP Internet protocol; an LO local oscillator; LTE long term evolution; MAC medium access control; MBMS multimedia broadcast multicast service; multicast/broadcast over MBSFN single frequency networks; an MCH multicast channel; MIMO multiple input multiple output; MISO multiple input single output; an MME mobility management entity; MOP maximum output power; MPR maximum power savings; MU-MIMO multi-user MIMO; an NAS non-access stratum; an OBSAI open base station architecture interface; OFDM orthogonal frequency division multiplexing; OFDMA orthogonal frequency division multiple access; PAPR peak-to-average power ratio; PAR peak-to-average ratio; a PBCH physical broadcast channel; P-CCPCH main common control physical channel; PCFICH physical control format indicator channel; a PCH paging channel; a PDCCH physical downlink control channel; PDCP packet data convergence protocol; PDSCH physical downlink shared channel; a PHICH physical hybrid ARQ indicator channel; a PHY physical layer; a PRACH physical random access channel; a PMCH physical multicast channel; a PMI precoding matrix indicator; a P-SCH primary synchronization signal; a PUCCH physical uplink control channel; and a PUSCH physical uplink shared channel.

Other terms include: QAM quadrature amplitude modulation; QPSK quadrature phase shift keying; RACH random access channel; RAT radio access technology; RB resource blocks; an RF radio frequency; an RFDE RF design environment; RLC radio link control; RMC reference measurement channel; an RNC radio network controller; RRC radio resource control; RRM radio resource management; an RS reference signal; RSCP received signal code power; RSRP reference signal received power; RSRQ reference signal received quality; an RSSI received signal length indicator; SAE system architecture evolution; an SAP service access point; SC-FDMA single carrier frequency division multiple access; SFBC space-frequency block coding; an S-GW service gateway; SIMO single input multiple output; SISO single input single output; SNR signal-to-noise ratio; an SRS sounding reference signal; an S-SCH secondary synchronization signal; SU-MIMO single-user MIMO; TDD time division duplex; TDMA time division multiple access; TR technical report; a TrCH transport channel; TS technical specification; TTA telecommunications technology association; TTI transmission time interval; a UCI uplink control indicator; UE user equipment; UL uplink (transmission of user to base station); a UL-SCH uplink shared channel; UMB ultra mobile broadband; UMTS universal mobile telecommunications system; UTRA universal terrestrial radio access; UTRAN universal terrestrial radio access network; a VSA vector signal analyzer; W-CDMA wideband code division multiple access.

It should be noted that various aspects are described in connection with a terminal. A terminal can also be called a system, user equipment, subscriber unit, subscriber station, mobile, remote station, remote terminal, access terminal, user agent, or user device. The user device may be a cellular telephone, a wireless telephone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a PDA, a handheld device having wireless connection capability, a module within a terminal, a card (e.g., a PCMCIA card) that may be attached to or integrated within a host device, or other processing device connected to a wireless modem.

Moreover, various aspects of the claimed subject matter may be implemented as a method, apparatus, or article of manufacture using standard programming and/or engineering techniques to produce software, firmware, hardware, or any combination thereof to control a computer or computing components to implement various aspects of the claimed subject matter. 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 can include but are not limited to magnetic storage devices (e.g., hard disk, floppy disk, magnetic strip …), optical disks (e.g., Compact Disk (CD), Digital Versatile Disk (DVD) …), smart cards, and flash memory devices (e.g., card, stick, key drive …). Further, it should be appreciated that a carrier wave can be employed to carry computer-readable electronic data such as data for transmitting and receiving voice mail or for accessing a network such as a cellular network. Of course, those skilled in the art will recognize many modifications may be made to this configuration without departing from the scope or spirit of what is described herein.

What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the described embodiments are intended to embrace all such alterations, modifications and variations that fall within the scope and spirit 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 (34)

1. A method of providing a wireless protocol, comprising:

transmitting a transmission interval that facilitates switching between a downlink portion and an uplink portion of a wireless communication channel; and

utilizing one or more guard periods during the transmission interval to mitigate overlap of transmit frequencies between the downlink and uplink portions of the wireless communication channel.

2. The method of claim 1, the guard period comprising a configurable time reservation.

3. The method of claim 1, the guard period comprising at least one downlink pilot transmission structure (DwPTS).

4. The method of claim 3, the guard period comprising at least one uplink pilot transmission structure (UpPTS).

5. The method of claim 4, the guard period configured as a total period of approximately one millisecond.

6. The method of claim 4, the guard period configured to repeat with a period of approximately five or ten milliseconds.

7. The method of claim 4, the guard period configured as two particular time slots associated with eight traffic slots during an approximately ten millisecond interval.

8. The method of claim 7, further comprising: the ratio of downlink (d) to uplink (u) (d: u) includes 4: 4, 5: 3, 6: 2, or 3: 5.

9. The method of claim 4, the guard period configured as one particular time slot associated with nine traffic slots during an approximately ten millisecond interval.

10. The method of claim 9, further comprising: the ratio of downlink (d) to uplink (u) (d: u) includes 5: 4, 6: 3, 7: 2, or 4: 5.

11. The method of claim 1, the transmission interval is approximately five milliseconds.

12. The method of claim 11, the transmission interval comprising at least five subframes.

13. The method of claim 11, the transmission interval comprising at least eight traffic slots.

14. The method of claim 11, further comprising: at least one of a Packet Data Control Channel (PDCCH) or a Physical Broadcast Channel (PBCH) is generated for a portion of the eight traffic slots.

15. The method of claim 11, further comprising: at least one of a Primary Synchronization Signal (PSS) or a Secondary Synchronization Signal (SSS) is generated for a portion of the eight traffic slots.

16. The method of claim 11, further comprising: one or more resource blocks for a portion of the eight traffic slots are generated.

17. A communication device, comprising:

a memory that retains instructions for reserving one or more time periods in a radio frame protocol, a guard period for mitigating frequency overlap between downlink and uplink channels, the time periods comprising at least a downlink portion, an uplink portion, and a guard portion; and

a processor to execute the instructions.

18. The apparatus of claim 17, further comprising instructions to configure the time period.

19. The apparatus of claim 17, further comprising instructions for processing a traffic slot and a particular slot, wherein the particular slot defines the time period.

20. The apparatus of claim 19, further comprising instructions to configure a ratio between the traffic time slot and the particular time slot.

21. A communication device, comprising:

means for generating a transmission interval comprising one or more particular time periods for mitigating frequency overlap between downlink and uplink portions of wireless communication;

means for configuring the particular time period; and

means for configuring a ratio between the downlink and uplink portions of the wireless communication.

22. A computer program product, comprising:

a computer-readable medium, comprising:

code for reserving a downlink buffer period for a transmission interval;

code for allocating a guard period to the downlink period of the transmission interval; and

code for reserving an uplink buffer time period and the guard time period, wherein the downlink buffer time period, the guard time period, and the uplink buffer time period are used to facilitate switching between downlink and uplink wireless communication time periods.

23. A processor that executes the following instructions:

configuring at least one specific time period for controlling a time period between downlink and uplink portions of a radio broadcast;

transmitting a plurality of traffic periods in conjunction with transmitting the particular period; and

controlling switching between a downlink portion and an uplink portion of a radio broadcast using the specific time period and the traffic time period.

24. A method of providing a wireless protocol, comprising:

receiving a transmission interval that facilitates switching between a downlink portion and an uplink portion of a wireless communication protocol; and

processing one or more guard time periods during the transmission interval to mitigate frequency overlap between the downlink and uplink portions of the wireless communication protocol.

25. The method of claim 24, the guard period comprising a configurable portion of time.

26. The method of claim 25, the guard period comprising at least one downlink pilot transmission structure (DwPTS) and at least one uplink pilot transmission structure (UpPTS).

27. The method of claim 26, the guard period is configured as two particular time slots associated with eight traffic slots during an approximately 10 millisecond interval.

28. The method of claim 27, further comprising: the ratio of downlink (d) to uplink (u) (d: u) includes 4: 4, 5: 3, 6: 2, or 3: 5.

29. The method of claim 26, the guard period is configured as one particular time slot associated with nine traffic slots during an approximately ten millisecond interval.

30. The method of claim 29, further comprising: the ratio of downlink (d) to uplink (u) (d: u) includes: 5: 4, 6: 3, 7: 2, or 4: 5.

31. A communication device, comprising:

a memory that retains instructions for receiving one or more time periods in a radio frame protocol, a guard period for facilitating switching between downlink and uplink channels, the time periods comprising at least a downlink portion, an uplink portion, and a guard portion; and

a processor to execute the instructions.

32. A communication device, comprising:

means for receiving a transmission interval comprising one or more particular time periods for facilitating switching between downlink and uplink portions of wireless communication;

means for configuring the particular time period; and

means for configuring a ratio between the downlink and uplink portions of the wireless communication.

33. A computer program product, comprising:

a computer-readable medium, comprising:

code for receiving a downlink buffer period for a transmission interval;

code for processing a guard period in accordance with the downlink period of the transmission interval; and

code for processing an uplink buffer time period and the guard time period, wherein the downlink buffer time period, the guard time period, and the uplink buffer time period are used to facilitate switching between downlink and uplink wireless communication time periods.

34. A processor that executes the following instructions:

configuring at least one specific time period for controlling a time period between downlink and uplink portions of a radio broadcast;

receiving a plurality of traffic time periods in conjunction with receiving the particular time period; and

processing the specific time period and the traffic time period to control switching between a downlink portion and an uplink portion of the radio broadcast.