HK1164014B - Frequency hopping in a wireless communication network - Google Patents

Description

Frequency hopping in wireless communication networks

The present application claims priority from U.S. provisional application S/n.61/147,984 filed on 28 th month, 2009, application S/n.61/148,810 filed on 30 th month, 2009, application S/n.61/149,290 filed on 2 nd month, 2009, and application S/n.61/149,945 filed on 4 th month, 2009, which are entitled "method and apparatus for type-2PUSCH hopping in LTE," and are hereby incorporated by reference.

Background

I. Field of the invention

The present disclosure relates generally to communication, and more specifically to techniques for performing frequency hopping in a wireless communication network.

II. background

Wireless communication networks are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Examples of such multiple-access networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, orthogonal FDMA (ofdma) networks, and single carrier FDMA (SC-FDMA) networks.

A wireless communication network may include a number of base stations that can support communication for a number of User Equipment (UE). A UE may communicate with a base station via the downlink and uplink. The downlink (or forward link) refers to the communication link from the base stations to the UEs, and the uplink (or reverse link) refers to the communication link from the UEs to the base stations. The UE may send a data transmission on a resource allocated to the UE by the base station. It may be desirable to send the transmission with frequency hopping to achieve good performance.

SUMMARY

Techniques for performing frequency hopping in a wireless communication network are described herein. In one aspect, frequency hopping may be performed based on a hopping function and both cell Identity (ID) and system time information. The system time information may effectively extend the periodicity of the hopping function, which may ensure that frequency hopping is possible in various operating scenarios.

In one design, the UE may determine a cell ID of a cell and may obtain system time information for the cell. The system time information may include a System Frame Number (SFN) of the radio frame. The UE may determine resources to use for transmission with frequency hopping based on the cell ID and system time information. The UE may then send transmissions to the cell on the resources.

In one design, the UE may determine an initial value for each radio frame based on a cell ID and an SFN for the radio frame. The UE may initialize a pseudo-random number (PN) generator with an initial value for each radio frame. The UE may generate a PN sequence with the PN generator in each radio frame. The UE may determine a particular subband to use for transmission based on a hopping function and the PN sequence. The UE may also determine whether to use mirroring based on the mirroring function and the PN sequence. The UE may then determine resources to use for transmission in the particular subband based on whether mirroring is to be used. The PN sequence may be generated based on at least one bit (e.g., two Least Significant Bits (LSBs)) in the SFN in each radio frame. The hopping function and the mirroring function may have a periodicity of at least two (e.g., four) radio frames, although the PN generator may be initialized in each radio frame.

Various aspects and features of the disclosure are described in greater detail below.

Brief Description of Drawings

Fig. 1 illustrates a wireless communication network.

Fig. 2 shows an exemplary frame structure.

Fig. 3 shows an exemplary resource structure.

Fig. 4A and 4B show two designs of initial values of the PN generator.

Fig. 5 shows the generation of PN sequence segments for different radio frames.

Fig. 6 shows a module for determining resources with frequency hopping.

Fig. 7 illustrates the use of different PN offsets in different radio frames.

Fig. 8 shows a process for communication with frequency hopping.

Fig. 9 shows an apparatus for communication with frequency hopping.

Fig. 10 shows a block diagram of a base station and a UE.

Detailed Description

The techniques described herein may be used for various wireless communication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network may implement radio technologies such as Universal Terrestrial Radio Access (UTRA), CDMA2000, and so on. UTRA includes wideband CDMA (wcdma), time division synchronous CDMA (TD-SCDMA), and other variants of CDMA. cdma2000 covers IS-2000,The IS-95 and IS-856 standards. TDMA networks may implement radio technologies such as global system for mobile communications (GSM). OFDMA networks may implement methods such as evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE802.11(Wi-Fi), IEEE802.16(WiMAX), IEEE802.20, Flash-OFDMAnd so on. UTRA and E-UTRA are parts of the Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-advanced (LTE-A) in both Frequency Division Duplex (FDD) and Time Division Duplex (TDD) are new releases of UMTS that use E-UTRA with OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE-A, and GSM are described in literature from an organization named "third Generation partnership project" (3 GPP). cdma2000 and UMB are described in documents from an organization named "third generation partnership project 2" (3GPP 2). The techniques described herein may be used for the above-mentioned wireless networks and radio technologies as well as other wireless networks and radio technologies. For clarity, certain aspects of the techniques are described below for LTE, and LTE terminology is used in much of the description below.

Fig. 1 shows a wireless communication network 100, which may be an LTE network or some other wireless network. Network 100 may include several evolved node bs (enbs) 110 and other network entities. An eNB may be a station that communicates with UEs and may also be referred to as a node B, base station, access point, etc. Each eNB110 provides communication coverage for a particular geographic area and supports communication for UEs located within the coverage area. The term "cell" may refer to a coverage area of an eNB and/or an eNB subsystem serving this coverage area, depending on the context in which the term is used. An eNB may support one or more (e.g., three) cells.

UEs 120 may be distributed throughout the wireless network, and each UE may be stationary or mobile. A UE may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, etc. A UE may be a cellular telephone, a Personal Digital Assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless telephone, a Wireless Local Loop (WLL) station, a smart phone, a netbook, a smartbook, and so forth.

Fig. 2 shows a frame structure 200 used in LTE. The transmission timeline may be partitioned into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 milliseconds (ms)) and may be divided into 10 subframes with indices of 0 through 9. Each subframe may include two slots. Each radio frame may thus comprise 20 time slots with indices 0 to 19. Each slot may include Q symbol periods, where Q may be equal to 6 for an extended cyclic prefix or equal to 7 for a normal cyclic prefix.

LTE utilizes Orthogonal Frequency Division Multiplexing (OFDM) on the downlink and single carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition system bandwidth into multiple (N)_FFTMultiple) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain under OFDM and in the time domain under SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (N)_FFT) May depend on the system bandwidth. For example, N for a system bandwidth of 1.25, 2.5, 5, 10, or 20MHz_FFTMay be equal to 128, 256, 512, 1024 or 2048, respectively.

Fig. 3 shows a design of a resource structure 300 that may be used for downlink or uplink in LTE. In a state of having a total of N_FFTA plurality of resource blocks may be defined in each slot of the plurality of subcarriers. Each resource block can cover N in one time slot_SCOne subcarrier (e.g., N)_SC12 subcarriers). The number of resource blocks in each slot may depend on the system bandwidth and may range from 6 to 110. These resource blocks may also be referred to as Physical Resource Blocks (PRBs). Can also define N_sbA sub-band of N_sbMay depend on the system bandwidth. Each sub-band may includeA PRB.

Virtual Resource Blocks (VRBs) may also be defined to simplify resource allocation. The VRB may have the same size as the PRB and may cover N in one slot in the virtual domain_SCAnd (4) a subcarrier. VRBs may be mapped to PRBs based on a VRB-to-PRB mapping. VRBs may be allocated to a UE, and transmissions for the UE may be sent on PRBs to which the allocated VRBs are mapped.

In LTE, a UE may be assigned one or more VRBs for a Physical Uplink Shared Channel (PUSCH). The UE may send only data or may send both data and control information on this PUSCH. The UE may be configured for class 2PUSCH hopping and may map the assigned VRBs to different PRBs in different slots or subframes. Class 2PUSCH hopping is specified via a set of formulas that includes a hopping function f_Jumping(i) And a mirror function f_m(i) In that respect Jump function f_Jumping(i) A particular subband to be used for transmission is selected. Mirror function f_m(i) Indicating whether the PRB in the given location of the selected subband or the mirror location of the subband is to be used. A given location may be a distance x from one side of the ion band and a mirror location may be the same distance x from the opposite side of the sub-band.

The skip function and the mirror function can be expressed as:

formula (1)

Formula (2)

Wherein

n_sIs the index of the time slot used for transmission,

N_sbis the number of subbands, which may be furtherThe high-level layer is used for providing the data,

c (k) is a PN sequence,

current _ TX _ NB indicates in slot n_sThe transmission number of the transport block transmitted in (b),

"mod" denotes a modulo operation, an

Representing a floor operation.

For the hopping function shown in equation (1), subband hopping is not performed when there is only one subband, which alternates between two subbands when there are two subbands, and which hops to different subbands in a pseudo-random manner when there are more than two subbands. For a given index k, the PN sequence c (k) provides a 1-bit value that is either '0' or '1'. The sum term in equation (1) forms a 9-bit pseudo-random value with 9 consecutive bits in the PN sequence.

Inter-subframe hopping refers to hopping from subframe to subframe and using the same PRB in both slots of a given subframe. Intra-subframe and inter-subframe hopping refers to hopping from subframe to subframe and also hopping within two slots of a given subframe. The mirroring function has a value of either '0' or '1', where '0' indicates that mirroring is not used and '1' indicates that mirroring is used. For the mirroring function shown in equation (2), (i) mirroring is used in every other slot for intra-sub-frame and inter-sub-frame hopping when there is only one sub-band, (ii) mirroring depends on the current TX NB for inter-sub-frame hopping when there is only one sub-band, and (iii) mirroring depends on the PN sequence when there is more than one sub-band.

Is a time slot n_sThe PRBs used for transmission in (1) may be determined as follows:

formula (3)

Wherein

Formula (4)

Formula (5)

n_VRBIs the starting index of the assigned VRB from the scheduling grant,

is the number of PRBs in each subband,

is the jump offset provided by the higher layer, an

Representing a rounding operation.

The UE may receive a starting index n assigned to one or more VRBs of the UE from a scheduling grant for the UE_VRB. The UE may be based on n as shown in equation (4)_VRBTo calculateThe UE may then be based on the hopping function, the mirroring function, and as shown in equation (3)To calculateThe UE may then be based on as shown in equation (5)To calculate n_PRB. The UE may start at index n_PRBTransmits data and possibly also control information on one or more PRBs.

For class 2PUSCH hopping, all VRBs in a given cell hop synchronously. This may minimize the need to dynamically schedule PUSCH using a Physical Downlink Control Channel (PDCCH) to minimize resource fragmentation and collisions in the cell.

A PN generator may be used to generate the PN sequence c (k). The PN generator may use an initial value c at the beginning of each radio frame_InitialTo initialize. The initial value may be set toWhereinIs the cell ID of the cell. Since the cell ID is static, the same PN sequence is used in each radio frame, and the PN sequence has a periodicity of 10 ms.

Jump function f_Jumping(i) And a mirror function f_m(i) The index i of (a) may correspond to a slot for intra-subframe and inter-subframe hopping or a subframe for inter-subframe hopping. Since a PN sequence c (k) with a periodicity of 10ms is used, the periodicity of the hopping and mirroring functions is fixed at a radio frame of 10 ms. Thus, the index i ranges from 0 to 9 for inter-subframe hopping and from 0 to 19 for intra-subframe and inter-subframe hopping.

LTE supports data transmission with hybrid automatic repeat request (HARQ). For HARQ on the uplink, the UE may send a transmission of a transport block and, if needed, one or more supplemental transmissions of the transport block until the transport block is decoded correctly by the eNB, or a maximum number of transmissions have been sent, or some other termination condition is encountered. Each transmission of the transport block may be referred to as a HARQ transmission. HARQ Round Trip Time (RTT) refers to the time interval between two consecutive HARQ transmissions of a given transport block and may be 8ms, 10ms, etc. LTE also supports Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD). The operation of HARQ may be different for FDD and TDD.

For 10 msharqrrtt, there is more than one sub-band (N)_sb(> 1), the hopping function in equation (1) and the mirroring function in equation (2) do not hop for HARQ transmissions of the same transport block. For 8msHARQRTT, there are two sub-bands (N)_sb2), the hopping function in equation (1) does not hop for HARQ transmissions of the same transport block due to its nature of alternating between two sub-bands in successive subframes. Performance may be degraded because the hopping function does not hop for the 10 msharqrrtt case and does not hop for the 8 msharqrrtt case with two subbands.

In one aspect, frequency hopping may be ensured for all operating scenarios by using both cell ID and system time information for the hopping function. The system time information may effectively extend the periodicity of the hopping function to be longer than the harqrrtt. This, in turn, may allow different subbands to be selected for different HARQ transmissions for a given transport block.

In one design, the system time information may include an SFN of a radio frame. LTE uses a 10-bit SFN, so these radio frames are numbered from 0 to 1023 and then wrap back to 0. In general, periodicity of any duration may be obtained for the hopping function by using appropriate time-domain parameters for system time information. In one design, the periodicity of the hopping function may be set to match the periodicity of a Physical Broadcast Channel (PBCH) that carries the SFN and other system information. The PBCH has a periodicity of 40ms or 4 radio frames. The two Least Significant Bits (LSBs) of the SFN may be used as a time domain parameter to obtain a periodicity of 40ms for the hopping function of class 2PUSCH hopping in LTE.

In a first frequency hopping design, both cell ID and SFN may be used to initialize the PN generators, and the hopping function may utilize the PN sequences from the PN generators. The PN sequence c (k) in LTE can be expressed as:

c(k)＝[x₁(k+N_C)+x₂(k+N_C)]mod2, formula (6)

Wherein x₁(k+31)＝[x₁(k+3)+x₁(k)]mod2, formula (7)

x₂(k+31)＝[x₂(k+3)+x₂(k+2)+x₂(k+1)x₂(k)]mod2, and formula (8)

N_C＝1600.

As shown in equation (6), the PN sequence c (k) is based on two m-sequences x of length 31₁(k) And x₂(k) Generated. In each radio frame, x may be initialized with a 31-bit value 000..0001₁(k) Sequence and use 31 bit value c_InitialTo initialize x₂(k) And (4) sequencing. c. C_InitialCan be defined in various ways based on cell ID and SFN to be x in different radio frames₂(k) The sequences obtain different initial values.

FIG. 4A illustrates the definition of c based on cell ID and SFN_InitialA design of (2). In this design, the M LSBs of the SFN form c_InitialM LSB, L bit cell ID form c_InitialNext L more significant bits of c_InitialThe remaining bits of (A) are then filled with 0's, where L ≧ 1 and M ≧ 1 are typical. For the case where L is 9 and M is 2, c_InitialCan be expressed as:

formula (9)

Wherein n is_fIs SFN.

Equation (9) may be used to obtain the periodicity of 4 radio frames for the hopping function. The periodicity of K radio frames may be obtained as follows, where K may be any suitable value:

formula (10)

FIG. 4B illustrates defining c based on cell ID and SFN_InitialIn another design of (4). In this design, the L-bit cell ID forms c_InitialL LSBs of SFN, M LSBs of SFN form c_InitialNext M more significant bits of c_InitialThe remaining bits of (A) are then filled with 0's, where L ≧ 1 and M ≧ 1 are typical. For the case where L is 9 and M is 2, c_InitialCan be expressed as:

formula (11)

The periodicity of the K radio frames may be obtained as follows:

formula (12)

As shown in FIGS. 4A and 4B and equations (9) to (12), c_InitialMay be defined based on the entire cell ID, for example by multiplying the cell ID by a factor of 4 in equation (9). This may ensure that neighbor cells assigned with different cell IDs will use different PN sequences for frequency hopping.

Fig. 5 shows the generation of PN sequences c (k) in different radio frames based on the design shown in equation (9) or (11). Radio frame t is a radio frame with SFN t, where t is within the range 0 to 1023 for a 10-bit SFN. For radio frame 0, c is obtained as 0 (SFNmod4)_InitialAnd using this c_{First stage Starting point}The generated PN sequence segment can be marked as c₀(k) And may be used in radio frame 0. For radio frame 1, c is obtained as 1 (SFNmod4)_InitialAnd using this c_InitialThe generated PN sequence segment can be marked as c₁(k) And can be atUsed in radio frame 1. For radio frame 2, c is obtained as 2 (SFNmod4)_InitialAnd using this c_InitialThe generated PN sequence segment can be marked as c₂(k) And may be used in radio frame 2. For radio frame 3, c is obtained as 3 (SFNmod4)_InitialAnd using this c_InitialThe generated PN sequence segment can be marked as c₃(k) And may be used in radio frame 3. For radio frame 4, c is obtained as 0 (SFNmod4)_InitialAnd use the PN sequence segment c in the radio frame 4₀(k) In that respect Four different PN sequence segments c₀(k)、c₁(k)、c₂(k) And c₃(k) Four different c's can be used_InitialValues are generated and may be used for each group of four consecutive radio frames as shown in fig. 5. These four PN sequence segments correspond to different portions of the PN sequence c (k) defined by equation (6).

In one design, the jump function may be defined as follows:

formula (13)

In equation (13), a PN sequence c (k) may be generated based on the cell ID and the SFN as described above. The hopping function in equation (13) will be achieved by using different PN sequence segments c in different radio frames₀(k) To c₃(k) To hop for the 10 msharqrrtt case. The hopping function will also hop for the 8 msharqrrtt and two sub-band case by using the PN sequence to select a sub-band instead of alternating between two sub-bands in successive subframes.

In another design, the second portion of equation (13) may be used for the case of two subbands and the third portion of equation (1) may be used for the case of more than two subbands. The hopping function can also be defined in other ways by the PN sequence c (k).

The mirror function in equation (2) may be used with the PN sequence c (k) generated based on the cell ID and SFN. In this case, the mirror function will be periodic over more than one radio frame and will hop for 10 msharqrrtt.

Fig. 6 shows a design of a module 600 for determining PRBs to be used for transmission based on this first frequency hopping design. Unit 612 may receive a cell ID and an SFN of a radio frame and may provide an initial value c for the radio frame_InitialFor example, as shown in the formula (9), (10), (11) or (12). PN generator 614 may be initialized with initial values in each radio frame and may generate a PN sequence segment for the radio frame, e.g., as shown in equation (6). Unit 616 may receive the PN sequence segments and other parameters for each radio frame and may determine the particular subband to use for transmission based on the hopping function, e.g., as shown in equation (13). Unit 618 may also receive the PN sequence segments and other parameters for each radio frame and may determine whether to use mirroring based on a mirroring function, e.g., as shown in equation (2). Unit 620 may receive the subband from unit 616, an indication from unit 618 whether mirroring is used, and other parameters. Unit 620 may determine PRBs to use for transmission based on all of these inputs, e.g., as shown in equations (3) through (5).

For this first frequency hopping design, different c's may be used in different radio frames_InitialThe values generate different segments of the PN sequence c (k). These different PN sequence segments can be used in the hopping function and the mirroring function to obtain longer periodicity. The PN sequence segment for each radio frame may be generated on the fly at the beginning of the radio frame. Alternatively, these PN sequence segments may be pre-computed, stored in a look-up table, and accessed as needed.

In a second frequency hopping design, the PN generator can be initialized with only the cell ID, and the hopping function and the mirroring function can utilize the PN sequence from the PN generator and the offset determined by the SFN. In this design, the same c may be used in each radio frame_InitialValues, e.g.To generate the same PN sequence c (k). Longer periodicity for the hopping and mirroring functions can be obtained by using different offsets of the PN sequence in different radio frames. In one design, the jump and mirror functions may be defined as follows:

formula (14)

Formula (15)

Wherein n is_fmodK is an offset that may be different for different radio frames, and

k ≧ 1 is a desirable periodicity in terms of radio frame number, e.g., K ≧ 4.

The design in equation (14) uses overlapping PN bits for the summation term in the second part. Specifically, 10 PN bits c (k) to c (k +9) may be used in the summation for radio frame 0, 10 PNs c (k +1) to c (k +10) may be used in the summation for radio frame 1, 10 PN bits c (k +2) to c (k +11) may be used in the summation for radio frame 2, and so on. To avoid overlapping PN bits in the summation, the hopping function can be defined as follows:

formula (16)

If K ═ 4, then equation (16) can be expressed as:

formula (17)

The hopping function and the mirroring function may also be defined in other ways using the offset of the PN sequence c (k). The use of the offset allows the PN sequence to be generated for all radio frames at once.

Fig. 7 shows the use of different offsets for the PN sequence c (k) in different radio frames based on the design shown in equation (14), (16) or (17). The same PN sequence c (k) may be used in each radio frame. An offset of offset0 may be used for the PN sequence in radio frame 0, an offset of offset1 may be used for the PN sequence in radio frame 1, an offset of offset2 may be used for the PN sequence in radio frame 2, an offset of offset3 may be used for the PN sequence in radio frame 3, an offset of offset0 may be used for the PN sequence in radio frame 4, and so on. The periodicity of the hopping and mirroring functions can be extended by using different offsets in different radio frames.

In general, system time information (e.g., SFN) can be used as an offset in the initialization of a PN generator to generate different PN sequence segments or as an offset to the same PN sequence. In either case, the offset may be selected such that (i) adjacent cells will not collide with the same PN sequence and/or (ii) adjacent subframes or slots will not collide with the same portion of the same PN sequence. The system time information may also be used in other ways to extend the periodicity of the hopping and mirroring functions.

The first and second frequency hopping designs described above may have the following advantages:

the periodicity of the hopping and mirroring functions can be extended, for example to 40ms by using offsets 0, 1, 2 and 3 in relation to the SFN,

all VRBs in a given cell hop synchronously,

the eNB and UE are likely to be synchronized for hopping and mirroring functions, since these UEs are required to acquire the SFN from the eNB,

hops are ensured for 8ms and 10 msharqrrtt and for both FDD and TDD,

the new jump and mirror function should be as easy to implement as the original jump and mirror function in equations (1) and (2), and

the impact on the LTE specifications may be minimal.

The UE is typically aware of the SFN of the serving cell and is thus able to perform a type 2PUSCH hopping as described above. The SFN may not be known by the UE in certain scenarios, e.g., upon handover to a new cell, upon re-accessing a cell after being out of synchronization with uplink timing, etc. In each of these scenarios, the UE may perform a random access procedure to access the cell. For a random access procedure, the UE may send a random access preamble (or message 1) on a Random Access Channel (RACH), receive a Random Access Response (RAR) grant from a cell, RAR (or message 2), and send a scheduled transmission (or message 3) on a PUSCH according to the RAR grant. The UE may not successfully decode the PBCH and may not timely acquire the SFN for transmission of message 3 on the PUSCH. The probability of such an event may be very low because the SFN is transmitted every 10 ms. In addition, it may be safely assumed that the UE will acquire the SFN after the RACH procedure and be able to perform a class 2PUSCH hopping for subsequent PUSCH transmissions.

The potential problem of SFN being temporarily unavailable to the UE during random access procedures (e.g., for handover and resynchronization) may be solved in various ways. In one design, which may be referred to as alternative I, message 3 and other transmissions on the PUSCH may be delayed until the SFN is acquired by the UE. The Medium Access Control (MAC) at the UE may consider the random access attempt to be unsuccessful even though message 2 has been received from the cell. The UE may then proceed with the retry procedure (e.g., retry or repeat the random access procedure with message 2). This will delay the random access procedure. However, since this is a low probability event, the impact on overall performance is negligible. In addition, this behavior may be limited to the case where the UE receives a RAR grant (or a grant via Downlink Control Information (DCI) format 0) with type 2PUSCH hopping enabled. From the UE's perspective, if the UE receives a RAR grant with type 2PUSCH hopping enabled (or a grant via DCI format 0) but has not acquired a SFN, the UE may treat the RAR grant as an invalid uplink assignment and may not transmit a PUSCH with type 2PUSCH hopping. The eNB may decide whether to use class 2PUSCH hopping for this case.

In another design, which may be referred to as alternative II, it may be assumed that the SFN was acquired by the UE after the random access procedure, if not earlier. One or more of the following options may then be used:

option 1: no designation is made in the LTE standard. The eNB implementation may enable or disable class 2PUSCH hopping in DCI format 0 for message 3.

Option 2: for message 3 transmission, class 2PUSCH hopping is disabled, where the corresponding bits in DCI format 0 can be reserved. This requires minimal standard changes and eliminates the need to handle this rare error event.

Option 3: for message 3 transmission, assume SFN-0. When SFN is 0, hopping is actually disabled for 10 msharqrrtt, but can be enabled using the design described above.

Option 4: the UE may set SFN 0 when it receives message 2 and may then increment SFN by 1 every 10ms until after a successful message 3 transmission is achieved. The type 2PUSCH hopping in this case may be UE-specific rather than cell-specific, and the PUSCH hopping for message 3 may not be synchronized with other PUSCH transmissions.

Option 5: a bit is introduced in DCI format 0 to indicate whether SFN should be reset for class 2PUSCH hopping. For example, if the position is set to 0, the UE may use the current SFN in the functions described above if available. Otherwise, the UE may assume SFN 0.

Option 6: SFN reset is introduced in relation to the threshold. For example, if the assignment size is to be greater than a certain threshold, the SFN may be reset to 0. The impact on uplink interference due to erroneous PUSCH transmissions may be limited with this option.

For these options described above, the handling of message 3 can be classified into two possibilities as follows:

m1: only those messages that are susceptible to potential SFN confusion, e.g. handover, resynchronization, and

m2: all messages, whether susceptible to SFN confusion or not.

Class 2PUSCH hopping can also be classified into two possibilities:

h1: for N_sbPerforming PUSCH hopping class 2 all at not less than 2, an

H2: with respect to N_sbAll perform class 2PUSCH hopping. I.e. even for N_sb＝1，

The designs described above may also be applicable.

Alternative II, option 2 may be interpreted as applicable to the following scenario:

m1+ H1: for messages 3 susceptible to potential SFN confusion, at N_sbForbidding the 2 nd PUSCH hopping under the condition of being more than or equal to 2,

m2+ H1: for message 3, whether it is susceptible to SFN confusion or not, at N_sbThe class 2PUSCH hopping is forbidden under the condition of being more than or equal to 2,

m1+ H2: for messages 3 susceptible to potential SFN confusion, no matter N_sbFor all, disabling the type 2PUSCH hopping, an

M2+ H2: message 3, whether or not it is susceptible to SFN confusion, N_sbFor which the type 2PUSCH hopping is disabled.

Alternative II, option 3 may be interpreted as applicable to the following scenario:

m1+ H1, M2+ H1, M1+ H2, and M2+ H2.

Similar concepts apply to the other options described above. The same option may apply if there is SFN confusion for PUSCH transmission (e.g., the UE has not acquired SFN upon handover after the random access procedure).

An alternative to class 2PUSCH hopping is to utilize the current _ TX _ NB, which indicates the total number of HARQ transmissions for a given transport block. Using this attribute for class 2PUSCH hopping has two disadvantages. First, the eNB and UE may be out of sync in the sense of the current _ TX _ NB. Thus, the UE may use some erroneous PRBs for PUSCH transmission and may interfere with other PUSCH transmissions. Second, the type 2PUSCH hopping in a cell will be UE specific, since the current _ TX _ NB is a UE specific parameter. The UE-specific parameters may force the eNB to use dynamic scheduling to reduce resource fragmentation. Option 5 and/or option 6 described above may be used to address potential out-of-sync issues.

In another design, a default mode may be defined instead of disabling type 2PUSCH hopping for message 3 transmissions. Default mode settable N_sbBecause it is not dependent on SFN 1. In particular, when the UE receives an uplink assignment for message 3 transmission with type 2PUSCH hopping, the UE may treat it as N_sbTreated as 1 regardless of the actual N of the cell_sbHow configured. This may be similar to the pair N_sbThe default mode SFN of 2 is 0 operation, as proposed for one of the options listed above. Message 3 transmission in this default mode may mean either the M1 possibility listed above or the M2 possibility listed above.

Fig. 8 shows a design of a process 800 for band-hopping communications in a wireless communication network. Process 800 may be performed by a UE, a base station/eNB, or some other entity. A cell ID of the cell may be determined (block 812). System time information for the cell may be obtained (block 814). In one design, the system time information may include an SFN of a radio frame. The system time information may also include other information related to the system time of the cell. The resources to be used for transmission with frequency hopping may be determined based on the cell ID and system time information (block 816). In one design shown in fig. 8, the UE may perform process 800 and may send transmissions to the cell on these resources (block 818). In another design not shown in fig. 8, the base station may perform process 800 and may receive transmissions sent by the UE to the cell on these resources.

In one design of block 816, the PN generator may be initialized based on the cell ID and the system time information. A PN sequence may be generated with the PN generator. The resources to be used for the transmission may then be determined based on the PN sequence. In one design of initializing the PN generator, the initial value (e.g., c) of the PN generator in each radio frame_Initial) The determination may be based on the cell ID and the SFN of the radio frame, for example, as shown in equation (9), (10), (11), or (12). The initial value may include L bits for a cell ID, M bits for M LSBs of an SFN, where L and M may each be 1 or greater, e.g., as shown in fig. 4A or 4B. The PN generator may then be initialized in each radio frame with the initial values for that radio frame. In another design, the PN generator may be initialized in each radio frame with an initial value determined based only on the cell ID, e.g., an initial value equal to the cell ID.

In one design of block 816, a PN sequence may be generated based on the cell ID and the SFN in each radio frame. The particular subband to use for transmission may be determined based on a hopping function and a PN sequence, e.g., as shown in equation (13). Whether mirroring is used may be determined based on the mirroring function and the PN sequence, for example, as shown in equation (2). The resources to be used for transmission may be determined based on the particular subband and whether mirroring is used, e.g., as shown in equation (3). The PN sequence may be generated based on at least one bit (e.g., two LSBs) of the SFN in each radio frame. The hopping function and the mirroring function may have a periodicity of at least two (e.g., four) radio frames, although the PN generator is initialized in each radio frame.

In another design of block 816, the PN sequence may be generated based on the cell ID in each radio frame. The offset for each radio frame may be determined based on the SFN. For example, the offset may be (n)_fmodK)、10(n_fmodK), etc. The subband to be used for transmission may be determined based on a hopping function, a PN sequence, and an offset, e.g., as shown in equation (14), (15), (16), or (17). Whether mirroring is used may also be determined based on the mirroring function, the PN sequence, and the offset, for example, as shown in equation (15). The resources to be used for transmission may be determined based on the particular subband and whether mirroring is used.

The UE may perform process 800 and may obtain system time information from a broadcast channel transmitted by a cell. The UE may avoid transmissions with frequency hopping if system time information is not available, or during random access procedures, and/or in other scenarios. The UE may receive an assignment with frequency hopping and may treat the assignment as invalid if system time information is not available. The UE may also use a default system time information value or a default number of subbands for the hopping function if system time information is not available.

In one design for LTE, a UE may obtain an assignment of at least one VRB from a cell. The UE may map the at least one VRB to at least one PRB based on a hopping function and a PN sequence generated based on a cell ID and system time information. The UE may send a transmission to the cell on the at least one PRB for the PUSCH. The UE may also send transmissions for other wireless networks in other manners.

Fig. 9 shows a design of an apparatus 900 for band-hopping communication in a wireless communication network. Apparatus 900 includes a module 912 to determine a cell ID for a cell, a module 914 to obtain system time information for the cell, and a module 916 to determine resources to use for transmission with frequency hopping based on the cell ID and the system time information. In one design shown in fig. 9, the apparatus may be for a UE and may also include a module 918 for sending transmissions from the UE to a cell on the resources. In another design not shown in fig. 9, the apparatus may be for a base station/eNB and may also include means for receiving transmissions sent by the UE to the cell on the resources.

The modules in fig. 9 may comprise processors, electronics devices, hardware devices, electronics components, logic circuits, memories, software codes, firmware codes, etc., or any combination thereof.

Fig. 10 shows a block diagram of a design of eNB/base station 110 and UE120, which may be one of the enbs and one of the UEs in fig. 1. eNB110 may be equipped with T antennas 1034a through 1034T and UE120 may be equipped with R antennas 1052a through 1052R, where generally T ≧ 1 and R ≧ 1.

At eNB110, a transmit processor 1020 may receive data from a data source 1012 for one or more UEs, process (e.g., encode, interleave, and modulate) the data for each UE based on one or more modulation and coding schemes for the UE, and provide data symbols for all UEs. The transmit processor may also process control information (e.g., cell ID, SFN, assignment, etc.) from controller/processor 1040 and provide control symbols. A Transmit (TX) multiple-input multiple-output (MIMO) processor 1030 may multiplex the data symbols, control symbols, and/or pilot symbols. A tx mimo processor 1030 may perform spatial processing (e.g., precoding) on the multiplexed symbols, as applicable, and provides T output symbol streams to T Modulators (MODs) 1032a through 1032T. Each modulator 1032 may process a respective output symbol stream (e.g., for implementing OFDM) to obtain an output sample stream. Each modulator 1032 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 1032a through 1032T may be transmitted via T antennas 1034a through 1034T, respectively.

At UE120, antennas 1052a through 1052r may receive the downlink signals from eNB110 and provide received signals to demodulators (DEMODs) 1054a through 1054r, respectively. Each demodulator 1054 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain received samples. Each demodulator 1054 may also process the received samples (e.g., for implementing OFDM) to obtain received symbols. A MIMO detector 1056 may obtain received symbols from all R demodulators 1054a through 1054R, perform MIMO detection on the received symbols, if applicable, and provide detected symbols. A receive processor 1058 can process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded control information (e.g., cell ID, SFN, assignment, etc.) to a controller/processor 1080, and provide decoded data for UE120 to a data sink 1060.

On the uplink, at the UE120, data from a data source 1062 and control information from the controller/processor 1080 may be processed by a transmit processor 1064, which transmit processor 1064 may perform frequency hopping as described above. The symbols from transmit processor 1064 may be precoded by a TXMIMO processor 1066 if applicable, conditioned by modulators 1054a through 1054r, and transmitted to the eNB 110. At eNB110, the uplink signals from UE120 may be received by antennas 1034, processed by demodulators 1032, processed by a MIMO detector 1036 where applicable, and further processed by a receive processor 1038 to obtain the data and control information transmitted by UE 120.

Controllers/processors 1040 and 1080 may direct the operation at eNB110 and UE120, respectively. Processor 1064, processor 1080, and/or other processors and modules at UE120 may implement module 600 in fig. 6 and/or process 800 in fig. 8 for data transmission with frequency hopping on the uplink. Processor 1038, processor 1040, and/or other processors and modules at eNB110 may also implement module 600 in fig. 6 and/or implement process 800 in fig. 8 for data reception with frequency hopping on the uplink. Data transmission and data reception with frequency hopping on the downlink may be performed in a manner similar to or different from data transmission and data reception with frequency hopping on the uplink. Memories 1042 and 1082 may store data and program codes for eNB110 and UE120, respectively. A scheduler 1044 may schedule UEs for downlink and/or uplink transmission and may provide resource (e.g., VRB) assignments for the scheduled UEs.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the disclosure herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more exemplary designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of instructions or data structures and which can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a web site, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk (disk) and disc (disc), as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks (disks) usually reproduce data magnetically, while discs (discs) reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (33)

1. A method for wireless communication, comprising:

determining, by a User Equipment (UE), a cell Identity (ID) of a cell;

obtaining, by the UE, system time information for the cell;

determining resource blocks to be used for transmission with frequency hopping by using the cell ID and the system time information for a hopping function, each resource block covering a predetermined number of subcarriers in a predetermined time interval; and

sending a transmission from the UE to the cell on the resource block.

2. The method of claim 1, wherein the system time information comprises a System Frame Number (SFN) and wherein the determining the resource block comprises determining the resource block based on L bits of the cell ID and M least significant bits of the SFN, wherein L and M are each greater than 1.

3. The method of claim 1, wherein the system time information comprises a System Frame Number (SFN) and wherein the determining the resource block comprises determining the resource block based on 9 bits of the cell ID and 2 Least Significant Bits (LSBs) of the SFN.

4. The method of claim 1, wherein the determining resource blocks to use for transmission comprises:

initializing a pseudo-random number (PN) generator based on the cell ID and the system time information,

generating a PN sequence with the PN generator, an

Determining the resource blocks to be used for transmission based on the PN sequence.

5. The method of claim 4, wherein the system time information comprises a System Frame Number (SFN), and wherein the initializing PN generator comprises:

determining an initial value for the PN generator in each radio frame based on the cell ID and the SFN of the radio frame, an

The PN generator is initialized with an initial value of each radio frame in each radio frame.

6. The method of claim 5, wherein initial values of the PN generator in each radio frame comprise L bits for the cell ID and M bits for M Least Significant Bits (LSBs) of the SFN, wherein L and M are each 1 or greater.

7. The method of claim 1, wherein the system time information comprises a System Frame Number (SFN), and wherein the determining resource blocks to use for transmission comprises:

generating a pseudo-random number (PN) sequence based on the cell ID and the SFN in each radio frame,

determining a sub-band to be used for transmission based on the hopping function and the PN sequence, an

Determining the resource blocks to be used for transmission based on the subbands.

8. The method of claim 4, wherein the determining resource blocks to use for transmission further comprises:

determining whether to use mirroring based on a mirroring function and the PN sequence, an

Determining the resource blocks to use for transmission further based on whether mirroring is determined to be used.

9. The method of claim 7, wherein the PN sequence is generated in each radio frame based on at least one least significant bit in the SFN, and wherein the hopping function has a periodicity of at least two radio frames.

10. The method of claim 7, wherein the PN sequence is generated in each radio frame based on two Least Significant Bits (LSBs) of the SFN, and wherein the hopping function has a periodicity of four radio frames.

11. The method of claim 1, wherein the determining resource blocks to use for transmission comprises:

determining a pseudo-random number (PN) sequence based on the cell ID and the system time information, an

Determining the resource blocks to be used for transmission based on an overall function that includes the hopping function and a mirroring function, the hopping function and the mirroring function being based on the PN sequence.

12. The method of claim 11, further comprising:

initializing a PN generator for generating the PN sequence based on:

whereinRepresents the cell ID of the cell or cells,

n_findicating a system frame number corresponding to the system time information,

c_initialRepresents an initial value for initializing the PN generator,

mod denotes a modulo operation.

13. The method of claim 1, further comprising:

the system time information is obtained from a broadcast channel transmitted by the cell.

14. The method of claim 1, further comprising:

if the system time information is not available, no transmission with frequency hopping is performed.

15. The method of claim 1, further comprising:

no transmission with frequency hopping is performed during the random access procedure.

16. The method of claim 1, further comprising:

receiving an assignment with frequency hopping; and

treating the assignment as invalid if the system time information is not available.

17. The method of claim 7, further comprising:

if the SFN is not available, a default value or a default number of sub-bands for the SFN is used for the hopping function.

18. The method of claim 1, wherein the determining resource blocks to use for transmission comprises:

obtaining an assignment of at least one Virtual Resource Block (VRB) from the cell, an

Map the at least one VRB to at least one Physical Resource Block (PRB) based on the hopping function and a pseudo-random number (PN) sequence generated based on the cell ID and the system time information, and wherein sending a transmission on the resource block comprises sending the transmission from the UE to the cell on the at least one PRB for a Physical Uplink Shared Channel (PUSCH).

19. An apparatus for wireless communication, comprising:

means for determining, by a User Equipment (UE), a cell Identity (ID) of a cell;

means for obtaining, by the UE, system time information for the cell;

means for determining resources to be used for transmission with frequency hopping by using the cell ID and the system time information for a hopping function, each resource block covering a predetermined number of subcarriers in a predetermined time interval; and

means for sending a transmission from the UE to the cell on the resource block.

20. The apparatus of claim 19, wherein the means for determining resource blocks to use for transmission comprises:

means for initializing a pseudo-random number (PN) generator based on the cell ID and the system time information,

means for generating PN sequences with said PN generator, and

means for determining the resource blocks to use for transmission based on the PN sequence.

21. The apparatus of claim 20, wherein the system time information comprises a System Frame Number (SFN), and wherein the means for initializing the PN generator comprises:

means for determining an initial value of the PN generator in each radio frame based on the cell ID and the SFN of the radio frame,

means for initializing the PN generator with an initial value of each radio frame in each radio frame.

22. The apparatus of claim 19, wherein the system time information comprises a System Frame Number (SFN), and wherein the means for determining resource blocks to use for transmission comprises:

means for generating a pseudo-random number (PN) sequence based on the cell ID and the SFN in each radio frame,

means for determining a subband to be used for transmission based on the hopping function and the PN sequence, an

Means for determining the resource blocks to use for transmission based on the subbands.

23. The apparatus of claim 20, wherein the means for determining resource blocks to use for transmission further comprises:

means for determining whether to use mirroring based on a mirroring function and the PN sequence, an

Means for determining the resource blocks to use for transmission further based on whether mirroring is determined to be used.

24. The apparatus as recited in claim 19, further comprising:

means for obtaining the system time information from a broadcast channel transmitted by the cell.

25. The apparatus of claim 19, wherein the means for determining resource blocks to use for transmission comprises:

means for obtaining an assignment of at least one Virtual Resource Block (VRB) from the cell, and

means for mapping the at least one VRB to at least one Physical Resource Block (PRB) based on the hopping function and a pseudo-random number (PN) sequence generated based on the cell ID and the system time information, and wherein means for sending a transmission on the resource block comprises means for sending the transmission from the UE to the cell on the at least one PRB for a Physical Uplink Shared Channel (PUSCH).

26. An apparatus for wireless communication, comprising:

at least one processor configured to determine a cell Identity (ID) of a cell, obtain system time information for the cell, determine resource blocks to use for transmission with frequency hopping by using the cell ID and the system time information for a hopping function, each resource block covering a predetermined number of subcarriers in a predetermined time interval, and

a transmitter configured to send a transmission from a UE to the cell on the resource block.

27. The apparatus of claim 26, wherein the at least one processor is configured to initialize a pseudo-random number (PN) generator based on the cell ID and the system time information, to generate a PN sequence with the PN generator, and to determine the resource blocks to use for transmission based on the PN sequence.

28. The apparatus of claim 27, wherein the system time information comprises a System Frame Number (SFN), and wherein the at least one processor is configured to determine an initial value for the PN generator in each radio frame based on the cell ID and the SFN of the radio frame, and to initialize the PN generator with the initial value of the radio frame in each radio frame.

29. The apparatus of claim 26, wherein the system time information comprises a System Frame Number (SFN), and wherein the at least one processor is configured to generate a pseudo-random number (PN) sequence based on the cell ID and the SFN in each radio frame, to determine a subband to use for transmission based on the hopping function and the PN sequence, and to determine the resource block to use for transmission based on the subband.

30. The apparatus of claim 27, wherein the at least one processor is configured to determine whether to use mirroring based on a mirroring function and the PN sequence, and to determine the resource block to use for transmission further based on whether to determine to use mirroring.

31. The apparatus of claim 29, wherein the PN sequence is generated in each radio frame based on two Least Significant Bits (LSBs) of the SFN, and wherein the hopping function has a periodicity of four radio frames.

32. The apparatus of claim 26, wherein the at least one processor is configured to obtain the system time information from a broadcast channel sent by the cell.

33. The apparatus of claim 26, wherein the at least one processor is configured to obtain an assignment of at least one Virtual Resource Block (VRB) from the cell, to map the at least one VRB to at least one Physical Resource Block (PRB) based on the hopping function and a pseudo-random number (PN) sequence generated based on the cell ID and the system time information, and the transmitter is further configured to send the transmission from the UE to the cell on the at least one PRB for a Physical Uplink Shared Channel (PUSCH).