深海游弋的鱼 – 默默的点滴

Using GNU Radio for Signal Phase Measurements

继续阅读Using GNU Radio for Signal Phase Measurements

SDR数模转换芯片相关的技术参数手册

常用的芯片技术参数PDF手册
继续阅读SDR数模转换芯片相关的技术参数手册

Determining RF Angle of Arrival Using COTS Antenna Arrays: A Field Evaluation

Determining RF Angle of Arrival Using COTS

Antenna Arrays: A Field Evaluation

继续阅读Determining RF Angle of Arrival Using COTS Antenna Arrays: A Field Evaluation

ubuntu 16.04规避srsLTE报告”Sequence number synch failure“的BUG

参考ubuntu 16.04系统LimeSDR使用srsLTE搭建LTE实验环境构建实验环境,在实际运行时候，手机设备无法正常连接到基站，报告如下错误信息：

Received Attach Request 
Attach Request -- IMSI-style attach request
Attach Request -- UE is already attached.Attach request -- IMSI: 208920100001100
Attach request -- eNB-UE S1AP Id: 3, MME-UE S1AP Id: 3
Attach request -- Attach type: 2
Attach Request -- UE Network Capabilities EEA: 11110000
Attach Request -- UE Network Capabilities EIA: 11110000
Attach Request -- MS Network Capabilities Present: true
PDN Connectivity Request -- EPS Bearer Identity requested: 0
PDN Connectivity Request -- Procedure Transaction Id: 1
PDN Connectivity Request -- ESM Information Transfer requested: false
Downlink NAS: Sending Authentication Request
Plain UL NAS: Authentication Failure
Sequence number synch failure
Downlink NAS: Sent Authentication Request
DL NAS: Sent Downlink NAS Message. DL NAS Count=0, UL NAS count=1
DL NAS: MME UE S1AP id 3
Plain UL NAS: Authentication Failure
Sequence number synch failure
Downlink NAS: Sent Authentication Request
DL NAS: Sent Downlink NAS Message. DL NAS Count=0, UL NAS count=2
DL NAS: MME UE S1AP id 3
Received UE Context Release Request. MME-UE S1AP Id 3
UE is not ECM connected. No need to release S1-U. MME UE S1AP Id 3
UE is ECM IDLE.

Received Attach Request

Attach Request -- IMSI-style attach request

Attach Request -- UE is already attached.Attach request -- IMSI: 208920100001100

Attach request -- eNB-UE S1AP Id: 3, MME-UE S1AP Id: 3

Attach request -- Attach type: 2

Attach Request -- UE Network Capabilities EEA: 11110000

Attach Request -- UE Network Capabilities EIA: 11110000

Attach Request -- MS Network Capabilities Present: true

PDN Connectivity Request -- EPS Bearer Identity requested: 0

PDN Connectivity Request -- Procedure Transaction Id: 1

PDN Connectivity Request -- ESM Information Transfer requested: false

Downlink NAS: Sending Authentication Request

Plain UL NAS: Authentication Failure

Sequence number synch failure

Downlink NAS: Sent Authentication Request

DL NAS: Sent Downlink NAS Message. DL NAS Count=0, UL NAS count=1

DL NAS: MME UE S1AP id 3

Plain UL NAS: Authentication Failure

Sequence number synch failure

Downlink NAS: Sent Authentication Request

DL NAS: Sent Downlink NAS Message. DL NAS Count=0, UL NAS count=2

DL NAS: MME UE S1AP id 3

Received UE Context Release Request. MME-UE S1AP Id 3

UE is not ECM connected. No need to release S1-U. MME UE S1AP Id 3

UE is ECM IDLE.

初步分析BUG的原因是如下函数在重新生成同步序列号的时候出现错误：

bool resync_sqn_milenage(uint64_t imsi, uint8_t *auts)

1 2	bool resync_sqn_milenage(uint64_t imsi, uint8_t *auts)

目前还在分析，目前出现这个现象的时候，当EPC退出时候，应用一定向user_db.csv回写000000001b02，一旦出现这个数字，我们就没办法注册设备了。

目前的应对办法是把user_db.csv最后的SQN，要比设备最后一次通信记录的数据号大，如果SQN数字复位，可以让设备关机，应该就从0开始了。此问题还在持续跟进中。

ubuntu 16.04用HackRF和Gqrx来听FM广播

$ sudo apt-get install hackrf

$ sudo apt-get install gqrx-sdr

#gqrx的配置文件在~/.config/gqrx目录下，如果出现问题，直接删除这个目录即可

$ sudo gqrx

$ sudo apt-get install hackrf

$ sudo apt-get install gqrx-sdr

#gqrx的配置文件在~/.config/gqrx目录下，如果出现问题，直接删除这个目录即可

$ sudo gqrx

继续阅读ubuntu 16.04用HackRF和Gqrx来听FM广播

SecureAngle: Improving Wireless Security Using Angle-of-Arrival Information

SecureAngle: Improving Wireless Security Using
Angle-of-Arrival Information

继续阅读SecureAngle: Improving Wireless Security Using Angle-of-Arrival Information

TIMING-BASED LOCATION ESTIMATION FOR OFDM SIGNALS WITH APPLICATIONS IN LTE, WLAN AND WIMAX

TIMING-BASED LOCATION ESTIMATION FOR OFDM SIGNALS WITH APPLICATIONS IN LTE, WLAN AND WIMAX
继续阅读TIMING-BASED LOCATION ESTIMATION FOR OFDM SIGNALS WITH APPLICATIONS IN LTE, WLAN AND WIMAX

窄带信号&模拟信号的带宽

窄带信号

A-窄带定义

关于窄带信号的定义不唯一，先从实际情况入手分析分析，例如一般谱估计需要2*π*d*sin(θ)/λ，当窄带信号入射进来（窄带也有一定带宽）：

继续阅读窄带信号&模拟信号的带宽

DOA estimation based on MUSIC algorithm

继续阅读DOA estimation based on MUSIC algorithm

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分类： Software defined Radio

ArrayTrack: A Fine-Grained Indoor Location System

Using GNU Radio for Signal Phase Measurements